Chapter 2
Prevention of Disease

Prevention is better than cure.

—Desiderius Erasmus

Preventing disease involves a wide range of interrelated programs, actions, and activities. Some prevention measures are sweeping global policy initiatives, such as national and state government actions to reduce health risks by limiting air pollution and other toxic exposures or standards to assure the safety of food and water supplies. Others are focused efforts of public health professionals and agencies, such as the National Institutes of Health (NIH) Office of Disease Prevention, Centers for Disease Control and Prevention (CDC), and the American Cancer Society, to reduce the incidence (occurrence of new cases) of specific diseases such as heart disease, diabetes, and lung cancer.

The effectiveness of global and local disease prevention programs largely depends on the extent to which individuals take personal responsibility for their own health by avoiding health risks such as tobacco use, substance abuse (misuse of alcohol and drugs), and unsafe sex. People who eat healthy diets; get adequate exercise and rest; wear seatbelts in automobiles and helmets on bikes, motorcycles, and scooters; successfully manage stress; and maintain positive outlooks on life are on the front lines of disease prevention. Similarly, individuals who effectively use health care resources by obtaining recommended immunizations, physical examinations, and health screenings are actively working to prevent disease and disability.

Prevention involves governments, professional organizations, public health professionals, health care practitioners (physicians, nurses, and allied health professionals), and individuals working at three levels to maintain and improve the health of communities. One level, known as primary prevention, is inhibiting the development of disease before it occurs. Secondary prevention, also called "screening," refers to measures that detect disease before it is symptomatic. Tertiary prevention efforts focus on people already affected by disease and attempt to reduce resultant disability and restore functionality.

PRIMARY PREVENTION

Primary prevention measures fall into two categories. The first category includes actions to protect against disease and disability, such as getting immunizations, ensuring the supply of safe drinking water, applying dental sealants to prevent tooth decay, and guarding against accidents. Examples of primary prevention of accidents include government and state requirements for workplace safety to prevent industrial injuries and equipping automobiles with air bags and antilock brakes. Examples of primary prevention of mental health problems include measures to strengthen family and community support systems as well as teaching children communication and interpersonal skills, conflict management, and other relationship and life skills that foster emotional resiliency.

General action to promote health is the other category of primary prevention measures. Health promotion includes the basic activities of a healthy lifestyle: good nutrition and hygiene, adequate exercise and rest, and avoidance of environmental and health risks. Limiting exposure to sunlight, using sunscreen, and wearing protective clothing are examples of primary prevention measures to reduce the risk of developing skin cancer.

Health promotion also includes education about the other interdependent dimensions of health known as wellness. Examples of health education programs aimed at wellness include stress management, parenting classes, preparation for retirement from the workforce, and cooking classes.

Historically, public health programs in developed countries have emphasized the primary prevention of infectious diseases (illnesses caused by microorganisms) by making environmental changes, such as improving the safety and purity of food and water supplies and providing immunizations. Table 2.1 shows the 2006 recommended schedule of childhood and adolescent immunizations—a key primary prevention measure in the United States and other developed countries.

Today, the most pressing health problems in developed countries are chronic diseases, such as heart disease, cancer, and diabetes, and obesity. Primary prevention of chronic diseases is more challenging than primary prevention of infectious diseases because it requires changing health behaviors. Efforts to change deeply rooted and often culturally influenced patterns of behaviors, such as diet, alcohol and tobacco use, and physical inactivity, generally have been less successful than environmental health and immunization programs.

Primary prevention programs are developed in response to actual and potential threats to community public health. Recent primary prevention programs have examined ways to prevent youth violence and acts of bioterrorism (use of biological or chemical weapons).

Primary Prevention of Youth Violence

Violence on high school campuses across the United States has focused media attention on the problem of violence during childhood, adolescence, and young adulthood. In the 2003 Youth Risk Behavior Survey conducted by the CDC, more than 6% of students interviewed said they had carried a firearm at least once during the past month, and 17.1% had carried a weapon such as a gun, knife, or club.

According to the CDC's National Center for Injury Prevention and Control (NCIPC), 81% of homicide victims ages fifteen to twenty-four were killed with firearms in 1999. In fact, firearm-related homicides were the second-leading cause of injury death among teens ages fifteen to nineteen years and the third-leading cause of injury death among teens ages ten to fourteen. In 2002 homicide persisted as the second-leading cause of death among young people ages fifteen to twenty-four. (See Table 1.12 in Chapter 1.)

To develop programs to prevent violence and violent deaths among children and teens, the CDC followed a systematic public health approach to identify and describe the problem, design and evaluate measures to prevent the problem, and put those measures in place in the community. The approach that public health professionals use to develop all prevention programs consists of the following steps, some of which may be conducted simultaneously:

• Surveillance—The first step is to collect and analyze data to determine the size and scope of the problem. To understand youth violence, researchers looked at how many people were injured or killed as a result of youth violence. They looked at the ages, attitudes, school performance, family histories, and other characteristics of the children and teens that committed violent acts. They also noted when (day, night, weekends, summer, winter, spring, or fall) and where (school, home, public parks) violence occurred.

TABLE 2.2

Potential participant groups for interventions to prevent youth violence

All children and adolescents in a community

All children in a specific age group, school, grade

Children and adolescents with risk factors such as—
   use of alcohol or other drugs
   history of early aggression
   social or learning problems
   exposure to violence at home, in their neighborhood, or in the media
   parental drug or alcohol use
   friends who engage in problem behavior
   academic failure or poor commitment to school
   poverty
   recent divorce, relocation, or other family disruption
   access to firearms

Children and adolescents with high-risk behaviors such as—
   criminal activity
   fighting or victimization
   drug or alcohol abuse
   selling drugs
   carrying a weapon
   membership in a gang
   dropping out of school
   unemployment
   homelessness
   recent immigration

Parents and other family members

Influential adults such as—
   teachers
   coaches
   child care providers

General population of a community

source: "Table 2. Potential Participant Groups for Interventions to Prevent Youth Violence," in Best Practices of Youth Violence Prevention: A Sourcebook for Community Action, Centers for Disease Control and Prevention, June 2002, http://www.cdc.gov/ncipc/dvp/bestpractices/chapter1.pdf (accessed December 13, 2005)

• Determining the Cause—By analyzing the data collected in the surveillance process, researchers can identify the underlying causes of the problem. Once public health professionals know who is at risk for a particular problem and why a certain group is at risk they are better able to design actions to prevent it. Table 2.2, a list of potential participants for anti-youth-violence interventions, notes risk factors and high-risk behaviors likely to lead to violence among children and adolescents.
• Develop and Test Preventive Measures—Using the results of the data analysis, public health professionals develop prevention programs called interventions. These interventions target specific populations and may be conducted at specific locations. (See Table 2.3.) Before recommending widespread use of interventions, health professionals test the programs to find out if they work as effectively as hoped. Every intervention is evaluated to find out if it achieves its objectives. Table 2.4 is an example of a goal—reducing expulsions resulting from fights in middle schools—of an intervention and its measurable objectives.
• Implementation—During this phase the preventive measures found to be effective are communicated so they may be put into action. To communicate methods

  TABLE 2.3
  Possible settings for interventions to prevent youth violence
  source: "Table 3. Possible Settings for Interventions to Prevent Youth Violence," in Best Practices of Youth Violence Prevention: A Sourcebook for Community Action, Centers for Disease Control and Prevention, June 2002, http://www.cdc.gov/ncipc/dvp/bestpractices/chapter1.pdf (accessed December 13, 2005)
  General population of young people schools churches playgrounds youth activity centers homes shopping centers and malls movie theaters High-risk youth alternative schools juvenile justice facilities social service facilities mental health and medical care facilities hospital emergency departments recreation centers	Young children child care centers homes schools Parents homes workplaces churches community centers

  TABLE 2.4

  Example of a goal and its objectives to prevent youth violence

  Goal: Reduce expulsions resulting from fights in middle schools.

  Objectives:

  1. By 2000, offer a 25-lesson program in 6th-grade classes to help students develop social skills and learn nonaggressive responses appropriate for dealing with conflict.

     Who: Prevention specialists

     What: 1-hour sessions offered twice a week for one school year on topics such as self-understanding, conflict resolution, anger control, and prosocial actions

     How much: All 6th-grade classes

     When: By 2000

     Where: Columbia County schools

  2. By 2001, implement a school-wide program to mediate behavior problems and disputes between adolescents.

     Who: Teachers and peer mediators

     What: Weekly mediation clinics

     How much: All 6th-, 7th-, and 8th-grade students

     When: By 2001

     Where: Columbia County schools

  3. By 2002, reduce the number of fights among 8th-grade students from five per month to two per month.

     Who: Middle school students

     What: Incidents of physical aggression

     How much: Reduce by 60 percent

     When: By 2002

     Where: Columbia County schools

  4. By 2004, reduce by half the number of middle school students (grades 6 through 8) expelled because of fights or other disruptive incidents in the schools.

     Who: Middle school students

     What: Expulsions related to fights in schools

     How much: Reduce from an average of two per month to one per month

     When: By 2004

     Where: Columbia County schools

  source: "Table 4. Example of a Goal and Its Objectives," in Best Practices of Youth Violence Prevention: A Sourcebook for Community Action, Centers for Disease Control and Prevention, June 2002, http://www.cdc.gov/ncipc/dvp/bestpractices/chapter1.pdf (accessed December 13, 2005)

  to prevent violence among children and teens, the CDC conducted training programs, published articles in journals for public health workers and health care

  TABLE 2.5
  Mentoring activities
  source: "Table 7. Mentoring Activities," in Best Practices of Youth Violence Prevention: A Sourcebook for Community Action, Centers for Disease Control and Prevention, June 2002, http://www.cdc.gov/ncipc/dvp/bestpractices/chapter2b.pdf (accessed December 13, 2005)
  Social	Event-related (field trips)
  talking about life experiences	camping or hiking
  having lunch together	attending a concert or an art exhibit
  visiting the mentor's home	attending a sporting event
  Recreational	Life skills-related
  playing games or sports	developing a fitness or nutrition plan
  doing arts and crafts	attending a cooking class
  walking in the park	discussing proper etiquette
  going to the mall	participating in a public-speaking class
  Academic	Job- or career-related
  working on homework	visiting the mentor's workplace
  visiting the library	developing a resume
  reading together	talking about career options
  working on the computer	practicing interview skills
  Civic
  helping in a community clean-up effort
  working at a soup kitchen

  practitioners, and produced a book of recommended programs entitled Best Practices of Youth Violence Prevention: A Sourcebook for Community Action.
• Evaluation—After preventive measures or interventions have been implemented, they are evaluated to see if they have effectively prevented the problem.

The CDC's Best Practices of Youth Violence Prevention: A Sourcebook for Community Action includes programs aimed at families, parents with infants and small children, and youth considered to be at risk. The book recommends providing social services to strengthen families, improving communication skills, and mentoring. Mentoring pairs young people with adult role models who, by example, teach and support social skills. Table 2.5 shows some mentoring activities recommended in the sourcebook.

SECONDARY PREVENTION

The goal of secondary prevention is to identify and detect disease in its earliest stages, before noticeable symptoms develop, when it is most likely to be treated successfully. With early detection and diagnosis, it may be possible to cure a disease, slow its progression, prevent or minimize complications, and limit disability.

Another goal of secondary prevention is to prevent the spread of communicable diseases (illnesses that can be transmitted from one person to another). In the community, early identification and treatment of people with communicable diseases, such as sexually transmitted diseases, not only provides secondary prevention for those who are infected but also primary prevention for people who come in contact with infected individuals.

Like primary prevention, individual health care practitioners and public health agencies and organizations perform secondary prevention. An example of secondary prevention that is conducted by many different professionals (physicians, nurses, allied health professionals) in a variety of settings (medical offices, clinics, health fairs) is blood pressure screening to identify people with hypertension (high blood pressure). An example of mental health secondary prevention is the effort to identify young children with behavior problems in order to intervene early and prevent development of, or progression to, more serious mental disorders.

Table 2.6 shows preventive measures, recommended by the U.S. Preventive Services Task Force, that should be taken by healthy adult men, women, pregnant women, and children. The recommended preventive services include screening to detect and identify a wide range of conditions including high blood pressure, depression, obesity, and sexually transmitted diseases such as chlamydia and syphilis infection.

Secondary prevention plays an important role in diseases such as diabetes (a condition in which the body does not properly metabolize sugar), glaucoma (a disorder caused by too much fluid pressure inside the eyeball), breast cancer, and cancer of the cervix (the opening of the uterus). State and local health departments, voluntary health agencies, hospitals, medical clinics, schools, and physicians often conduct screenings for these conditions during which people with no signs or symptoms are tested to uncover these diseases in their earliest stages.

Screening and Early Detection of Breast and Cervical Cancers

Early detection through screening is our best defense against morbidity and mortality from breast and cervical cancers and precancers.

—Julie L. Gerberding, MD, MPH, Director, Centers for Disease Control and Prevention

The American Cancer Society (ACS) in Breast Cancer Facts and Figures 2005–2006 estimates that in 2005, 211,240 women were diagnosed with breast cancer and 40,410 died of the disease (2005, http://www.cancer.org/downloads/STT/CAFF2005BrF.pdf). And in Cancer Facts and Figures 2005, the ACS estimated that 10,370 new cases of cervical cancer were diagnosed in 2005 and 3,710 women died of the disease (2005, http://www.cancer.org/downloads/STT/CAFF2005f4PWSecured.pdf). As with many other cancers, treatment for these types of cancer is most likely to be successful when the disease begins, before the cancer has metastasized (spread from its original site to other parts of the body).

Mammography screening, or breast x-rays that find cancers too small to be detected by self-examination or manual examination by a health practitioner, could

prevent 16% of all breast cancer deaths in women older than age forty, according to the CDC in The Burden of Chronic Diseases and Their Risk Factors: National and State Perspectives (2004, http://www.cdc.gov/nccdphp/burdenbook2004/pdf/burden_book2004.pdf). Moreover, the risk reduction associated with screening increases as women age. The Papanicolaou test, also called Pap smear or Pap test, is a screening examination for cancer of the cervix that has the potential to prevent practically all deaths from cervical cancer by detecting cervical cancer at an early stage, when it is most curable, or even preventing the disease if precancerous lesions found during the test are treated. The incidence of cervical cancer has decreased dramatically in the past forty or so years thanks largely to screening and early treatment.

Although a new vaccine to immunize women against contracting the strain of human papilloma virus (HPV) that causes cervical cancer will be available in late 2006, it will only work in females who have not yet become sexually active and contracted the virus. For this reason cervical cancer screening will continue to be important for several generations after widespread immunization has occurred.

In 1990 Congress passed the Breast and Cervical Cancer Mortality Prevention Act, establishing the CDC's National Breast and Cervical Cancer Early Detection Program (NBCCEDP). The NBCCEDP provides breast and pelvic examinations, screening mammography, and Pap tests to women at greater risk of death from breast or cervical cancer—racial and ethnic minorities, those who live below the poverty level, older women, and women with less than a high school education.

By June 2003 NBCCEDP had screened nearly two million women, provided more than 4.6 million screening examinations, and diagnosed 17,009 breast cancers, 61,474 precancerous cervical lesions, and 1,157 cervical cancers. Figure 2.1 shows the numbers of women served by NBCCEDP for the years 1991–2003. A significant component of the NBCCEDP effort is community education and outreach. Health educators must not only communicate the life-saving benefits of screening and early identification of disease but also overcome barriers to access to care, such as lack of transportation or child care.

To inform and encourage women to seek screenings, public health workers present health education programs to women's groups, distribute brochures describing how and why women should be screened, and enlist the media to help spread the message. Print advertisements appear in newspapers and magazines to promote the NBCCEDP.

The NBCCEDP also funds follow-up care for women who have abnormal screening results to enable them to receive needed services. These may include biopsy (surgical removal of a sample of cells for microscopic examination) to confirm the diagnosis and visits with surgeons and other medical specialists to receive timely treatment. The provision of follow-up care and treatment is a fundamental principle underlying screening programs.

Screening programs that do not provide facilities for diagnosis and treatment are unlikely to be effective, especially when they are serving populations unable to pay for medical care. Further, many public health professionals believe it is unethical to offer screening without plans and provisions to care for disease identified through the screening process.

TERTIARY PREVENTION

Tertiary prevention programs aim to improve the quality of life for people with various diseases by limiting complications and disabilities, reducing the severity and progression of disease, and providing rehabilitation (therapy to restore functionality and self-sufficiency). Unlike primary and secondary prevention, tertiary prevention involves actual treatment for the disease and is conducted primarily by health care practitioners, rather than public health agencies.

Tertiary prevention efforts have demonstrated that it is possible to slow the natural course of some progressive diseases and prevent or delay many of the complications associated with chronic diseases such as arthritis (inflammation of the joints that causes pain, swelling, and stiffness), asthma (inflammation and obstruction of the airways that makes breathing difficult), heart disease, and diabetes.

An example of tertiary mental health prevention is outreach programs that monitor persons with mental disorders who live in the community to ensure that they adhere to their prescribed medication regimens. Such tertiary prevention programs have demonstrated efficacy in reducing acute psychiatric hospital admissions and long-term institutionalization and enabling persons with mental disorders to live independently.

Tertiary Prevention of Diabetes

Insulin is a hormone produced by the pancreas to control the amount of glucose (sugar) in the blood. Diabetes mellitus is a disease in which high blood glucose levels result from insufficient insulin production or action. When there is not enough insulin produced, the body is unable to metabolize (use, regulate, and store) glucose, and it remains in the blood.

Type 1 diabetes mellitus (also called insulin-dependent diabetes or juvenile-onset diabetes) occurs when pancreatic beta cells, the cells that make insulin, are destroyed by the body's own immune system. It usually develops in children and young adults. Because people with diabetes do not have enough insulin, they must be injected or inject themselves with insulin several times a day or receive insulin via a pump. About 5-10% of all diagnosed cases of diabetes are type 1.

Approximately 90-95% of all diagnosed cases of diabetes are type 2 diabetes mellitus (also called non-insulin-dependent diabetes or adult-onset diabetes). Type 2 diabetes occurs when the body becomes resistant to insulin. As a result of the cells being unable to use insulin effectively, the amount of glucose they can take up is sharply reduced and high levels of glucose accumulate in the blood.

People who are older than age forty, overweight, have a family history of diabetes, and are physically inactive are at greater risk of developing type 2 diabetes. There is an increased prevalence of diabetes with age. The percent of persons diagnosed with diabetes over age sixty (15.1%) is more than twice as high as for persons ages forty to fifty-nine (6.6%). (See Table 2.7.)

African-Americans, Hispanic/Latino Americans, Native Americans, and some Asian Americans and Pacific Islanders are at greater risk for type 2 diabetes. Table 2.7 shows that in 1999–2002, 5.3% of whites were diagnosed with diabetes by a physician, compared with 11.2% of African-Americans and 10.5% of Mexicans. Figure 2.2 shows that non-Hispanic African-Americans and Hispanic/Latino Americans are disproportionately affected and that American Indians/Alaska Natives age twenty years or older are more than two times as likely to have been diagnosed with diabetes in 2005 as non-Hispanic whites.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK is one of the institutes of the National Institutes of Health), 1.5 million new cases of diabetes were diagnosed in 2005, with the largest number of new diagnoses among persons ages forty to fifty-nine. (See Figure 2.3.) NIDDK reports that in 2005, 20.8 million people—7% of the U.S. population—had diabetes. Of this more than twenty million, 14.6 million were diagnosed and 6.2 million were undiagnosed (http://diabetes.niddk.nih.gov/dm/pubs/statistics/index.htm).

Many people with type 2 diabetes are able to control their blood sugar by losing excess weight, maintaining proper nutrition, and exercising regularly. Others require insulin injections or orally administered (taken by mouth) drugs to lower their blood sugar. Figure 2.4 shows that among adults diagnosed with diabetes in 2001–03, 16% take insulin only, 12% take both insulin and oral medication, 57% take only oral medication, and 15% take neither oral medication nor injected insulin.

Other types of diabetes can occur as a result of pregnancy (gestational diabetes) or physiologic stress such as surgery, trauma, malnutrition, infections, and other illnesses.

These types of diabetes account for about 5% of all diagnosed cases of the disease, according to the NIDDK.

A major public health concern is the more than six million Americans who are not aware that they have diabetes. The U.S. Department of Health and Human Services (HHS) reported that the number of adults in the United States with diagnosed diabetes (including women with gestational diabetes) increased 61% from 1991 to 2001 and is expected to more than double by 2050 (2003, http://www.healthierus.gov/steps/summit/prevportfolio/Diabetes-HHS.pdf).

COMPLICATIONS OF DIABETES

According to the NIDDK, adults with diabetes suffer from heart disease at much higher rates (two to four times higher than people without diabetes)—in fact, heart disease is the number-one cause of death among people with diabetes. Similarly, adults with diabetes are also at increased risk for stroke (damage to the brain that occurs when its blood supply is cut off, frequently because of blockage in an artery that supplies the brain) and hypertension (nearly three-fourths of adults with diabetes have high blood pressure). Together, heart disease and stroke account for about 65% of deaths in people with diabetes. Other serious complications of this disease include the following:

• Diabetic retinopathy—This is a condition that can cause blindness.
• Diabetic neuropathy—This condition causes damage to the nervous system that may produce pain or loss of sensation in the hands or feet and other nerve problems.
• Kidney disease—Diabetes accounts for almost half of all new end-stage renal disease cases that require dialysis (mechanical cleansing of the blood of impurities) or kidney transplant.
• Amputation—Diabetes is responsible for more than half of all lower-limb amputations (surgical removal of toes, feet, and the leg below the knee) performed in the United States.
• Dental disease—Gum diseases are common among people with diabetes, and nearly one-third of all people with diabetes have severe periodontal (tooth and gum) diseases.

• Problems with pregnancy—Diabetes may cause birth defects, spontaneous abortion (miscarriage), and excessively large babies that may create additional health risks for expectant mothers.

• Increased risk of infection—People with diabetes are more susceptible to infection and do not recover as quickly as people without diabetes.

Further, poorly controlled or uncontrolled diabetes may produce life-threatening medical emergencies, such as diabetic ketoacidosis (excessive ketones—chemicals in the blood resulting from insufficient insulin and an excessive amount of counterregulatory hormones such as glucagon) or hyperosmolar (extremely high blood glucose, leading to dehydration) coma.

Achieving optimal control of blood glucose levels can prevent many of the complications of diabetes and decrease the risk of death associated with the disease. Optimal control involves aggressive treatment of diabetes with close attention to the roles of diet, exercise, weight management, and pharmacology (proper use of insulin and other medication) in self-management of the disease.

PREVENTING COMPLICATIONS OF DIABETES

According to the CDC, diabetes researchers have determined that even modest improvement in controlling blood glucose acts to help prevent diabetic retinopathy, neuropathy, and kidney disease. Reducing blood pressure has the potential to reduce cardiovascular complications (heart disease and stroke) by as much as 50% and to reduce the risk of retinopathy, neuropathy, and kidney disease by almost one-third. Lowering blood cholesterol (a waxy substance produced by the body and also found in animal products), low-density lipoproteins (LDL), and triglycerides also reduces, by as much as 50%, the cardiovascular complications of diabetes. (Cholesterol, LDL, and triglycerides are lipids that may be measured in the blood.)

Early detection and treatment of diabetic eye disease can reduce the possibility of blindness or serious loss of vision by about 50%, the CDC reports. Similarly, early detection and treatment of kidney disease sharply reduces the risk of developing kidney failure, and careful attention to foot care reduces the risk of amputation by as much as 85%.

To help increase early detection of diabetes (secondary prevention) and reduce the morbidity (illnesses) and mortality (deaths) associated with it (tertiary prevention), the CDC and NIDDK launched the National Diabetes Education Program (NDEP) in 1998. The NDEP's objectives are to increase public awareness of diabetes, improve self-management of people with diabetes, enhance health care providers' knowledge and treatment of diabetes, and promote health policies that improve access, availability, and quality of diabetes care. To meet these educational objectives, the NDEP, working with a variety of other health organizations, develops and distributes teaching tools and resources.

Print advertising and patient education materials developed by the NDEP focus on personal responsibility for self-management of diabetes. For example, one print advertisement was translated from Spanish into English after it proved tremendously successful in Hispanic/Latino communities. The ad featured a photograph of a lightning bolt next to the heading: "There are many things in life that can't be controlled. Fortunately diabetes isn't one of them."

The 148-page NDEP patient information book also emphasizes the importance of self-care in the prevention of complications of diabetes. For example, the section on foot care explains, "There's a lot you can to do prevent problems with your feet. Controlling your blood glucose and not smoking or using tobacco can help protect your feet. You can also take some simple safeguards each day to care for and protect your feet." The section goes on to explain the importance of self-care habits such as having one's feet checked, washing them carefully, trimming toenails, taking care of corns and calluses, protecting feet from heat and cold, wearing shoes and socks, and remaining physically active.

EXEMPLARY MENTAL HEALTH PREVENTION PROGRAMS

This section presents a national mental health and suicide risk screening program for youth described in Achieving the Promise: Transforming Mental Health Care in America, published by the President's New Freedom Commission on Mental Health (2003, http://www.mentalhealthcommission.gov/reports/FinalReport/toc.html). This section also offers recommendations and descriptions of interventions considered effective at preventing suicide from a publication by the Committee on Pathophysiology and Prevention of Adolescent and Adult Suicide, Board of Neuroscience and Behavioral Health, of the Institute of Medicine (IOM): Reducing Suicide: A National Imperative (2002) (Washington, DC: National Academies Press, 2002, http://www.nap.edu/books/0309083214/html/).

The IOM's Reducing Suicide report characterizes current mental health prevention programs as rooted in the "universal, selective, and indicated (USI) prevention model." This model considers three defined populations—the entire population is included in universal programs, specific high-risk groups are targeted by selective programs, and indicated programs address specific high-risk individuals. Universal programming assumes a basically healthy population and generally aims at protection against developing a disorder by offering, for example, enhanced coping skills and resiliency training. Examples of universal programs are educational programs to heighten awareness of a problem and mass-media campaigns intended to increase understanding of and attitudes about a particular issue.

Population-based programs often produce greater gains than programs targeting individuals because there are higher rates of program participation. For example, all the students in a given grade will be exposed to school-based drug prevention programs. Selective programs target subsets of populations that have been identified as at risk but are not yet diagnosed with a specific problem or disorder—persons who have a greater-than-average likelihood of developing mental disorders, such as adolescents with truancy or suspected substance abuse problems. Indicated programs are aimed at specific high-risk individuals who have evidenced early signs or symptoms of mental disorders, such as children diagnosed with attention deficit hyperactivity disorder (ADHD) who may be at greater risk of developing conduct disorders, or students who have engaged in disruptive or other disturbed behavior at school.

By recounting the histories, benefits, and scientific evaluation of mental health prevention programs, these reports offer a framework for developing and implementing mental health prevention programs and policies in a wide range of settings, including primary medical care practices and clinics, maternal and infant health and mental health programs, child care centers, school-based health centers, vocational training programs, social service agencies, parent education programs, and the media. Further, these reports disseminate the methods and results of effective programs, enabling mental health service providers and other stakeholders throughout the country to replicate these results in their local communities.

Adolescent Intervention Programs

One recommendation from the report of the President's New Freedom Commission on Mental Health was to "improve and expand school mental health programs." It cited research demonstrating that about 42% of students with serious emotional disturbances graduate from high school, compared with 57% of students with other disabilities. The commission believed this could be changed, because it found ample evidence that school mental health programs improved academic achievement—with improved test scores, fewer absences, and less discipline problems—by detecting mental health problems early and providing timely referral to appropriate treatment.

The commission observed that the concerted effort needed to deliver quality mental health services in schools entailed collaboration with parents and local providers of mental health care to support screening, assessment, and early intervention. It also asserted that mental health services must be integral parts of school health centers and that federal funds must be available to support the programs.

The report lauded the Columbia University TeenScreen program as a model program of screening and early intervention. The program ensures mental health screening of all students before they leave high school and early identification of students at risk for suicide or those with symptoms of depression or other mental illness. Evaluation of the program found it to be remarkably effective—identifying more than 60% of students later found to have recurrent mental health problems or mental disorders. Table 2.8 summarizes the goals, features, outcomes, and principal challenges faced during implementation of the TeenScreen program.

Participants complete a ten-minute paper-and-pencil or computerized questionnaire. The questionnaires cover anxiety, depression, substance and alcohol abuse, and suicidal thoughts and behavior. The TeenScreen program does not recommend any particular type of treatment for the teens who are identified by the mental health screening. Parents of students identified as at possible risk are notified and offered information and referral to local mental health services where they can obtain further evaluation. No student is screened without parental consent, and the results of the screen are confidential. Screening occurs in a range of venues, including schools, clinics, physicians' offices, and juvenile justice facilities.

TeenScreen is supported by thirty-four national organizations, including the American Academy of Child and Adolescent Psychiatry, American Federation of Teachers, and the President's New Freedom Commission on Mental

Health, and is funded by private foundations and individuals. It operates by partnering with communities throughout the nation to implement local screening programs for youth. The local programs are developed in consultation with Columbia University to meet the specific needs and resources of each community. Programs range from one-day screening efforts to full-time, district-wide screening for all high school students. Columbia offers consultation, training, screening tools, and technical assistance to participating communities free-of-charge. By the close of 2005 TeenScreen operated eight national model programs and had developed partnerships to implement statewide screening programs with state agencies in Ohio, Florida, Pennsylvania, and Nevada.

TABLE 2.9

Suicide risk factors, protective factors, and national prevention strategy

• National Strategy for Suicide Prevention: AIM
  • Awareness: promote public awareness of suicide as a public health problem
  • Intervention: enhance services and programs
  • Methodology: advance the science of suicide prevention
• Risk factors
  • Male gender
  • Mental disorders, particularly depression and substance abuse
  • Prior suicide attempts
  • Unwillingness to seek help because of stigma
  • Barriers to accessing mental health treatment
  • Stressful life event/loss
  • Easy access to lethal methods such as guns
• Protective factors
  • Effective and appropriate clinical care for underlying disorders
  • Easy access to care
  • Support from family, community, and health and mental health care staff

source: Adapted from "Figure 4.1. Surgeon General's Call to Action to Prevent Suicide—1999," in Mental Health: A Report of the Surgeon General, U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, with NIH, 1999, http://www.mentalhealth.samhsa.gov/features/surgeongeneralreport/toc.asp (accessed December 15, 2005)

PREVENTING SUICIDE

The HHS's Mental Health: A Report of the Surgeon General (1999, http://www.surgeongeneral.gov/library/mentalhealth/home.html) termed suicide a serious public health problem and recommended a three-pronged national strategy to prevent suicide, which included programs to educate, heighten understanding, intervene, and advance the science of suicide prevention. Table 2.9 shows the components of AIM (awareness, intervention, and methodology)—the national strategy for suicide prevention—as well as risk factors and protective factors for suicide.

The IOM's Reducing Suicide described suicide as "a major national and international public health problem with about 30,000 deaths in the United States and 1,000,000 deaths in the world each year and every year."

In view of the magnitude of the problem, the IOM report called for development, testing, expansion, and implementation of programs for suicide prevention funded by appropriate agencies, including the National Institute of Mental Health (NIMH), the Department of Veterans' Affairs (DVA), the CDC, and the Substance Abuse Mental Health Services Administration (SAMHSA). Specific recommendations about prevention programs included:

• Creating partnerships among federal, state, and local agencies to implement effective suicide prevention programs
• Collaborating with professional societies, including the American Psychiatric Association and the American Psychological Association, and nonprofit organizations dedicated to the prevention of suicide, such as the American Association of Suicidology
• Expanding programs that have demonstrated success in select populations. For example, the Air Force program (see below) should be adopted by comparable organizations that experience increased suicide rates such as police and emergency rescue workers. There should be a systematic identification of high suicide risk groups for targeted intervention.
• Including coping and resiliency training in the curricula for school-aged children and intensifying or expanding these when feasible. In view of the link between cumulative life stresses and suicide and the existing data supporting the efficacy of these programs, it is expected that this training will act to reduce the frequency of suicidal behavior as well as other mental health disorders.
• Restricting access to common means of suicide by enacting or strengthening legislation to ensure gun safety, building barriers on bridges, modifying contents of cooking gas, reinforcing packaging of commonly used pills, and poison control
• Evaluating public education campaigns to determine and quantify their effectiveness to change knowledge and attitudes and to reduce suicide and suicidal behaviors

The Air Force Suicide Prevention Program

The IOM report considered a variety of prevention programs that address risk factors and aim to enhance protective factors in order to reduce the incidence of suicide and suicidal behaviors. It observed that programs that appear effective, such as one initiated by the U.S. Air Force, are comprehensive and simultaneously act to increase knowledge and change attitudes within a community, dispel barriers to treatment, and improve access to support and intervention.

The Air Force Suicide Prevention Program is a population-based, community approach to suicide risk prevention and behavioral health promotion that was named a "best practice initiative" by the assistant secretary for health of the HHS. It integrated human, medical, and mental health services, uniting a coalition of community agencies from within and outside of the health care delivery system to significantly reduce suicide among air force personnel, which had risen to an all-time high during the mid-1990s. Figure 2.5 shows suicide rates among air force personnel from 1990 to 2002.

The program attempted to reduce risk factors, such as problems with the law, finances, intimate relationships, mental health, job performance, substance abuse, social isolation, and poor coping skills. It simultaneously sought to strengthen protective factors such as effective coping skills, a sense of social connectedness, support, and policies and norms that encourage effective help-seeking behaviors. To stimulate help-seeking behaviors, the air force chief of staff forcefully communicated the urgent need for air force leaders, supervisors, and frontline workers to support one another during times of heightened life stress. He exhorted airmen to seek help from mental health clinics and observed that seeking help early was likely to enhance careers rather than hinder them. The chief of staff instructed commanders and supervisors to support and protect those who sought mental health care and eliminated policies that served as barriers to seeking and obtaining mental health care.

To improve surveillance, a Web-based database was established to capture demographic, risk factor, and protective factor information about individuals who attempted or completed suicide. This extremely secure tool protected privacy and permitted timely detection of changes in patterns in suicidal behavior that could be used to strengthen policies and enhance practices throughout the air force community. To improve crisis management, critical incident stress management teams were assembled and poised for deployment to installations hard hit by potentially traumatizing events such as combat deployments, serious aircraft accidents, and natural disasters, as well as suicides within the units.

When the program commenced in 1995, suicide was the second-leading cause of death among air force personnel. After its inception, the suicide rate declined significantly for three consecutive years. During the first six months in 1999 the rate dropped to less than 3.5 per one hundred thousand—more than 50% less than the lowest rate on record prior to 1995 and an 80% drop from the peak rates in the mid-1990s. Although the suicide rates increased in 2000 and early 2001, they declined again after and remained much lower than rates prior to 1995. (See Figure 2.5.)

The air force experience is not necessarily applicable to the general population, because the air force is a tightly controlled and relatively homogenous community with identifiable leaders readily able to influence community norms and priorities. It can still serve as a model for comparable hierarchical organizations and offers insight into prevention program planning. The program's overarching principles, such as engaging community leaders to change cultural norms, improving coordination of diverse human and health services, and providing educational programs to community members, can inform national efforts and may be replicable in other populations.

School-Based Prevention Programs

After reviewing eleven universal prevention strategies targeting high school students and more than fifteen programs aimed at younger students, the IOM report confirmed that school-based programs have demonstrated success in reducing suicidal behavior, but it also observed that effective school-based interventions were far more than simply awareness or education programs. Successful programs offer services such as screening, support, and skills training groups, and establish school-based crisis response plans and teams of professionals to enact the plans. They emphasize the importance of telling adults about emotional distress and seeking help for oneself or friends, as well as cultivation of the competence and skills that offer protection from the adverse effects of stress.

The IOM cited Reconnecting Youth, a personal competency training program piloted in five urban high schools as a model selective prevention program that uses a combination of support and skills training. Between 35% and 40% of youth at risk for academic failure are also at risk for suicide, so the program targeted potential high school dropouts. The program was offered as a single-semester, daily, fifty-five-minute elective class with one facilitator or teacher and about ten students. Participants completed a comprehensive suicide-risk assessment and learned a variety of skills that produced measurable gains in increasing personal control—self-efficacy, self-esteem, and reliance on social supports. Participants also reported decreased depression, hopelessness, anger, and stress.

The school-based prevention programs for youth identified as being at risk focused on enhancing students' feelings of personal control. The IOM report presented two programs, Counselors Care (C-CARE) and Project CAST (Coping and Support Training). C-CARE interventions targeted potential high school dropouts who had shown specific early signs of suicide and related risk factors and offered them an in-depth motivational interview that assessed a list of direct suicide risk factors, related risk factors, and protective factors. Following a one-on-one, two-hour assessment interview, participants received an additional two-hour counseling session and meetings with parents and school personnel, intended to strengthen social connections. A booster session, consisting of further assessment and counseling, was provided between six and eight weeks following the initial intervention.

Project CAST provided twelve sessions of small group skills training and case management along with the initial and booster sessions provided by C-CARE for a comparable target population. In addition to addressing school performance and drug use, the twelve sessions emphasized building personal resources such as self-esteem, personal control of moods, positive coping strategies, staying on track, and monitoring and setting goals. The sessions also concentrated on empathy and motivation as well as identifying support needs and resources, and how to access help and support.

Participants from both programs were followed and assessed on four different occasions, including nine months after completion of either program. Both programs were found to enhance self-esteem and reduce depression, anxiety, hopelessness, and anger. Each also decreased the use of "hard" drugs, but CAST was more effective at reducing alcohol and marijuana use and produced more enduring increases in problem solving, coping, and personal control. There were no measurable changes in suicide rates, but this finding is not surprising in view of the low risk of suicide during the limited follow-up period and the relatively small sample sizes of the populations.

Do Telephone Hotlines and Crisis Centers Prevent Suicide?

Although crisis centers and telephone hotlines that aim to prevent suicide attempts are ubiquitous, the IOM report observed that their effectiveness is unknown. The IOM recommended research to determine not only whether such services are effective preventive measures or deterrents but also which model of crisis counseling or telephone service is most effective. Is anonymous telephone counseling preferable to telephone counseling in which the caller must disclose his or her identity? Is face-to-face counseling a better intervention than telephone counseling in terms of connecting persons in crisis to mental health services they might otherwise fail to seek or obtain? Should crisis centers and telephone hotlines be staffed by professional mental health workers or trained volunteers? Finally, the IOM report encouraged researchers to consider whether provision of crisis intervention services via the Internet is a workable alternative, especially for youths who may be more comfortable seeking help online than in person or by telephone.

PREVENTION RESEARCH AND GOALS

In 1986 Congress funded the first Prevention Research Centers. As of 2006, thirty-three such centers were affiliated with medical schools or schools of public health. The centers explore and research a wide range of public health problems and test strategies to address those problems. Table 2.10 is a list of the Prevention Research Centers and the themes of research underway. In 2006 more than five hundred funded projects were examining programs addressing myriad prevention efforts such as childhood obesity, reducing smoking among Appalachian teens, promoting healthy aging, and workplace safety.

Primary prevention research and programming in the past has aimed to prevent illness by more effectively encouraging people to avoid behaviors (such as smoking, abusing drugs, engaging in unsafe sexual practices, and overeating) linked to health risk. Prevention research and education now also emphasize avoiding or reducing environmental exposures (such as sun, water pollution, radon, ozone, pesticides, and hazardous chemicals) that increase health risk.

Mental Health Prevention Research

The National Advisory Mental Health Council (NAMHC) advises the Secretary of Health and Human Services, the director of the NIH, and the director of the NIMH on policies and activities relating to mental health prevention research, research training, and other programs of the NIMH. In reports issued in 1991 and 2001, the NAMHC described a number of critically needed new areas for research that are essential for expanding prevention efforts in the field of mental health. These included:

• The NIMH definition of prevention research should be broader and should include studies of risk factors for mental illness, comorbidity of mental illnesses, and relapse and disability caused by mental illness.
• Prevention research should include not only individuals but also larger social units such as families, communities, and other social systems. It should also include public policy and laws that may influence the effectiveness of prevention interventions.
• More research should be conducted to determine how best to decrease relapse and disability in persons with major mental disabilities such as schizophrenia.
• More studies should be done to determine and quantify the cost-effectiveness of prevention programs.

• The NIMH fund should fund more research that integrates social, behavioral, and genetic risk factors into prevention interventions.
• More research should be conducted on strategies, programs, and community interventions to prevent depression and aggression.
• The NIMH should fund more research on common sets of risk factors that occur early in life and lead to a variety of adolescent and adult disorders. Specifically, the workgroup advised research about these early risk factors and about interventions to modify these early risk factors in order to eliminate or at least reduce their impact and resultant negative outcomes.
• There should be increased emphasis on theory and research on the adoption, implementation, and dissemination of prevention research findings.

SATISFYING WORK, SOCIAL ACTIVITIES, AND PERSONAL RELATIONSHIPS ARE KEY TO HEALTH AND WELLNESS

Family, friends, active interests, and community involvement may do more than simply help people enjoy their lives. Social activities and relationships actually may enable people to live longer by preventing or delaying development of many diseases, including dementia. During the past two decades research has demonstrated that social experiences, activities, relationships, and work stress are related to health, well-being, and longevity. The kind of work stress that causes the greatest harm to physical and mental health is effort-reward imbalance—when great effort is made and the effort is neither recognized nor rewarded. Although women appear more vulnerable to job stress, men's health seems more dependent on the availability of social relationships and emotional support.

Several studies have shown that marriage or living with a partner has greater health benefits for men than women, because traditionally women are caregivers. Newer findings question whether the nurturing qualities of women are solely responsible for married men's improved health. Recent research reveals that men and women living alone have better health than those with unsatisfactory relationships with their partners. An alternative explanation of these findings may be that healthier people are more likely to marry than those with health problems.

Dr. Laura Fratiglioni and her colleagues at the Stockholm Gerontology Research Centre found that among Swedish older adults, the risk of developing dementia increased with increased social isolation ("Influence of Social Network on Occurrence of Dementia: A Community-based Longitudinal Study," Lancet, vol. 355, no. 9212, April 15, 2000). The quality, rather than frequency, of social contacts was more important in staving off impairment. People who had infrequent but satisfying interactions with families and friends fared better than those with unhappy or stressful relationships. The Swedish project also suggests that a variety of strong relationships is important—a single bond is insufficient to reduce risk. Older adults with several kinds of enduring relationships such as marriage, children, friends, and relatives were at lowest risk.

A promising finding from this study is the observation that one relationship may substitute for another. This is a key concern because death of a spouse or close friend may increase the survivor's risk for social isolation. The observation that strong connections with children, relatives, and friends can substitute for relationships with spouses or partners is especially significant for widowed, divorced, or never-married older adults.

Along with personal relationships, social activities also seem to protect against disease and increase longevity, even when the activities do not involve physical exercise. An annual study tracked the health and longevity of 2,761 older adults living in New Haven, Connecticut (Thomas A. Glass et al, "Population Based Study of Social and Productive Activities as Predicators of Survival among Elderly Americans," British Medial Journal, August 21, 1999). After thirteen years the researchers determined that "social and productive activities that involve little or no enhancement of fitness lower the risk of all cause mortality as much as fitness activities do."

Recent research reiterated the health benefits of socialization. Data from the Framingham Heart Study (a landmark study of fifty years of data about the health of residents of Framingham, Massachusetts) presented at the American Heart Association's Annual Conference on Cardiovascular Disease Epidemiology and Prevention in May 2005 found that men who were socially isolated had elevated levels of interleukin-6 (IL-6), a blood marker for inflammation that is linked to heart disease. The investigators posited that IL-6 may be elevated in men who are socially isolated because social isolation may influence health behaviors such as smoking and physical activity, which act to raise IL-6 levels. In addition, socially isolated people are often depressed and experience more stress than their more gregarious counterparts, and research has demonstrated that stress can increase IL-6 levels (Eric B. Loucks, "Social Connections: Could Heartwarming Be Heart-saving?" Meeting Report, Abstract P226 [EPI], American Heart Association, May 1, 2005, http://www.americanheart.org/presenter.jhtml?identifier=3030595).

Pets Are More Than Best Friends: They Can Help Keep People Healthy

Research conducted during the late 1990s found that pet ownership was associated with better health. At first it was believed that the effects were simply increased well-being—the obvious delight of hospital and nursing home patients petting puppies, watching kittens play, or viewing fish in an aquarium clearly demonstrated pets' abilities to enhance mood and stimulate social interactions.

A study published in the Journal of the American Geriatrics Society (vol. 47, no. 3, March 1999) found that attachment to a companion animal was linked to maintaining or slightly improving the physical and psychological well-being of older adults. Parminder Raina and his colleagues followed nearly one thousand older adults for one year and found that pet owners were better able to perform the activities of daily living and were more satisfied with their physical health, mental health, family relationships, living arrangements, finances, and friends. These findings were confirmed further by a study published in the December 2002 issue of Psychosomatic Medicine (J. Blascovich and B. Mendes, vol. 64, no. 5) using both men and women and dogs and cats.

Other research revealed the specific health benefits of human interaction with animals. One study followed people who had suffered heart attacks and found that after one year pet owners had one-fifth of the mortality rate of people without pets. Several researchers have observed that petting dogs and cats actually lowers blood pressure. The physiologic mechanisms responsible for these health benefits are as yet unidentified; however, some researchers think that pets connect people to the natural world, enabling them to focus on others, rather than simply on themselves. Other investigators observe that dog owners walk more than people without dogs and credit pet owners' improved health to exercise. Nearly all agree that the nonjudgmental affection pets offer boosts health and wellness.

Healthy People 2010

Building on the earlier reports Healthy People: The Surgeon General's Report on Health Promotion and Disease Prevention (1979) and Healthy People 2000: National Health Promotion and Disease Prevention Objectives (1990), Healthy People 2010 (November 2000, http://www.healthypeople.gov/document/html/uih/uih_2.htm) is an updated plan from the HHS detailing 467 objectives in twenty-eight focus areas to improve the nation's health. Its two general goals are to "help individuals of all ages increase life expectancy and improve the quality of life" and to "eliminate health disparities among different segments of the population."

Nearly all of the Healthy People 2010 goals and objectives involve one or more of the three levels of prevention. For example, the overall goal for cancer is to "reduce the number of new cancer cases as well as the illness, disability, and death caused by cancer." To realize this goal may involve primary prevention to encourage people to avoid known carcinogens (cancer-causing agents, such as tobacco) and secondary prevention to encourage screenings to detect cancer in its earliest, most readily treatable stages. An example involving tertiary prevention action is the focus on disability and secondary conditions that seeks to "promote the health of people with disabilities, prevent secondary conditions, and eliminate disparities between people with and without disabilities in the U.S. population."

Healthy People 2010 not only sets forth ambitious goals related to disease prevention but also outlines population-specific health and prevention objectives. For example, the publication includes twenty-one objectives related to adolescent health, ranging from reducing

TABLE 2.11

Twenty-one critical objectives identified by the Adolescent Health Work Group

• Reduce the proportion of children and adolescents with disabilities who are reported to be sad, unhappy, or depressed.
• Reduce pregnancies among adolescent females.
• (Developmental) Reduce the number of cases of HIV infection among adolescents and adults.
• Reduce deaths caused by motor vehicle crashes.
• Increase use of safety belts.
• Reduce homicides.
• Reduce physical fighting among adolescents.
• Reduce weapon carrying by adolescents on school property.
• Reduce deaths of adolescents and young adults.
• Reduce the suicide rate.
• Reduce the rate of suicide attempts by adolescents.
• (Developmental) Increase the proportion of children with mental health problems who receive treatment.
• Reduce the proportion of children and adolescents who are overweight or obese.
• Increase the proportion of adolescents who engage in vigorous physical activity that promotes cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion.
• Reduce the proportion of adolescents and young adults with chlamydia trachomatis infections.
• Increase the proportion of adolescents who abstain from sexual intercourse or use condoms if currently sexually active.
• Reduce deaths and injuries caused by alcohol- and drug-related motor vehicle crashes.
• Reduce the proportion of adolescents who report that they rode, during the previous 30 days, with a driver who had been drinking alcohol.
• Reduce past-month use of illicit substances.
• Reduce the proportion of persons engaging in binge drinking of alcoholic beverages.
• Reduce tobacco use by adolescents.

source: "21 Critical Objectives Identified by the Adolescent Health Work Group," in Healthy People 2010: Understanding and Improving Health, 2nd edition, U.S. Government Printing Office, 2000, http://www.healthypeople.gov/search/stat_21crobj.htm (accessed December 14, 2005)

violent deaths resulting from homicide and suicide to increasing seatbelt use. (See Table 2.11.)

Many Americans Believe Cancer Cannot Be Prevented

Despite widespread health and consumer education about lifestyle choices and behaviors that can help to reduce the risk of developing serious diseases, many Americans persist in the belief that there is little they can do to prevent disease. For example, a December 2005 survey commissioned by the American Cancer Society found that nearly half of survey respondents (47%) felt they had little or no control in terms of reducing their risk of developing cancer (Mike Stobbe, "Half Surveyed Doubt Cancer Preventable," Associated Press, January 19, 2006). The survey also found that 65% of people are very or somewhat concerned that they will get cancer. About 70% of people ages thirty-five to fifty-four were very or somewhat concerned, compared with 62% of people ages fifty-five to sixty-four, 55% of people ages sixty-five to seventy-five, and 47% of people seventy-five and older.