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![]() Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: mmwrq@cdc.gov. Type 508 Accommodation and the title of the report in the subject line of e-mail. Public Health Focus: Physical Activity and the Prevention of Coronary Heart DiseaseCoronary heart disease (CHD) is the leading cause of mortality in the United States: each year, CHD is newly diagnosed in approximately 1.5 million persons and accounts for an estimated $47 billion in direct and indirect health-care costs (1). Multiple risk factors associated with CHD include genetic susceptibility, elevated serum cholesterol, low levels of high-density lipoprotein cholesterol, cigarette smoking, uncontrolled hypertension, obesity, diabetes mellitus, and physical inactivity (2). This report summarizes information about the potential efficacy and cost-effectiveness of physical activity promotion as a strategy for preventing CHD. Efficacy and Attributable Risk Mild to moderate levels of physical activity (e.g., walking, gardening, yardwork, and dancing) can help prevent CHD. In 1987, a review of 43 epidemiologic studies concluded that moderate to vigorous physical activity reduces risk for CHD (3). Two thirds of the studies documented a substantial inverse relation between physical activity and risk for CHD. In addition, the risk for CHD was increased nearly twofold for persons who were physically inactive (relative risk=1.9; 95% confidence interval=1.4-2.5), a level comparable to the relative risks associated with increased systolic blood pressure (2.1), cigarette smoking (2.5), and elevated serum cholesterol (2.4) (4). A subsequent meta-analysis (5) and results from other longitudinal studies (6) support the role of physical inactivity as a strong and independent risk factor for CHD. Based on a national survey in 1985, 56% of men and 61% of women in the United States either never or irregularly engaged in physical activity (7). Specifically, 25% of men and 30% of women reported no leisure-time physical activity during the preceding month, and an additional 31% of men and women reported irregular physical activity. Of the 36% of men and 32% of women who were regularly active during leisure time, 8% of the men and 7% of the women reported participating in vigorous and intense activity (7). An estimate of the population-attributable risk for CHD mortality associated with physical inactivity among a selected group of men from 1977 through 1985 was 14% (6). In comparison, the risk for hypertension was 20%; for cigarette smoking, 13%; and for a positive family history of premature parental death, 20%. An analysis based on published studies and the U.S. death rate to estimate the number of deaths attributed to several risk factors for nine chronic diseases (8) indicated that, in 1986, a total of 205,254 deaths associated with CHD were attributed to never or irregularly engaging in physical activity -- a number in excess of estimates for smoking (148,879), obesity (190,456), and hypertension (171,121) but similar to the estimates for elevated serum cholesterol (253,194). Cost-Effectiveness Based on 1989 mortality estimates for CHD, the extrapolated cost of physical inactivity is $5.7 billion; among other risk factors for CHD, only elevated serum cholesterol (greater than or equal to 200 ug/dL) has a higher estimated cost (Table_1). A cost-effectiveness analysis to estimate the health and economic implications of a physical activity program in preventing CHD was conducted using a model of two hypothetical cohorts (one physically active and another inactive) of 1000 men aged 35 years (9). This analysis was based on a 30-year period to observe differences in the occurrence of CHD events, life expectancy, and quality-adjusted life expectancy. Physical activity was associated with 78 fewer CHD events and 1138 quality-adjusted life-years gained during the 30-year period. For each quality-adjusted life-year gained, the direct cost was $1395, and total cost was $11,313 -- amounts similar to the cost savings of other CHD intervention strategies (Table_2). In Canada, a program promoting physical activity in a selected worksite was evaluated after 12 years of operation (12). The program consisted of professionally led physical activity classes 2-3 times per week for 30-45 minutes per session; an onsite gymnasium and exercise equipment also were made available to employees of the company. Per capita medical claims were lower in the intervention site than in a control site having no promotion of physical activity (12). For each worker, the intervention program saved $679 in medical claims per year, a return of $6.85 on each dollar invested. Other examples of worksite-based programs have been estimated to cost employers approximately $100-$400 per employee per year (13). The estimated rate of return is $513 per employee year, which includes reduced health-care costs and reduced loss of productivity. Reported by: Div of Chronic Disease Control and Community Intervention, National Center for Chronic Disease Prevention and Health Promotion; Applications Br, Div of Surveillance and Epidemiology, and Prevention Effectiveness Activity, Epidemiology Program Office, CDC. Editorial NoteEditorial Note: Epidemiologic, clinical, and experimental evidence have established the association between physical activity and the prevention of CHD (3). The finding that moderate levels of physical activity reduce the risk for CHD indicates that inactive persons can benefit from even modest increases in their physical activity. Theoretical estimates suggest that, in the United States, 20,000 fewer persons would die per year if half of those persons with no leisure-time physical activity begin to participate in moderate physical activity (e.g., brisk walking) a minimum of 2-3 times per week (14 ). Biologic mechanisms through which physical activity may prevent CHD include improved weight control, enhanced glucose tolerance and insulin sensitivity, reduced blood pressure, improved coronary artery blood flow, and augmented high-density lipoprotein levels. Educating health professionals and lay persons to implement effective ways to reduce risk factors for CHD and subsequent disease could result in a substantial savings in health-care costs. To increase and promote levels of physical activity, health-care and public health providers should consider those factors associated with inactivity. In particular, prevalence of inactivity is higher among older persons and women. In addition, inactivity has been associated with cognitive factors (e.g., knowledge of the benefits of activity, the perception of poor health, lack of time, and dislike for activity), personal attributes (e.g., obesity, low educational attainment, lack of self-motivation, and lack of confidence in ability to perform an activity), and environmental factors (e.g., lack of social support, inconvenience of activities, aversion to vigorous activities, and cost of activities) (15). In addition to worksite-based programs, physical activity levels have been successfully increased in school-based programs for students, faculty, and staff and in the community (16). Community-based campaigns focusing on participation, awareness through media and education, and environmental efforts (e.g., increased access to trails, parks, and school facilities) have resulted in short-term improvements in the physical activity habits of targeted groups. Other potential sites for promoting physical activity include physician's offices and health clinics, as well as the home and neighborhood environment, where the emphasis should be on participation in a variety of self-directed, moderate-level physical activities (e.g., gardening, yardwork, and walking) with a goal of 30 minutes of activity per day at least 5 days per week. References
TABLE 1. Population attributable risk of coronary heart disease (CHD) deaths and estimated societal costs, by selected risk factors -- United States * ================================================================================================ Attributable risk (%) + Estimated cost Risk factor (n=593,111) (billions) & ---------------------------------------------------------------------------------------------- Physical inactivity 34.6 $5.7 Obesity 32.1 $5.3 Smoking 25.0 $4.1 Hypertension 28.9 $4.7 Elevated serum cholesterol (>=200 ug/dL) 42.7 $7.0 ---------------------------------------------------------------------------------------------- * Source: Reference 8. + Percentages cannot be summed because they are calculated independently for each risk factor. & Costs include hospital, physician, and nursing services; medicines; and lost productivity. ================================================================================================ Return to top. Table_2 Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size. TABLE 2. Selected risk factors for coronary heart disease, by prevalence, population- attributable risk, and cost effectiveness -- United States ============================================================================================ Risk factor Prevalence (%) Attributable risk (%) * Cost effectiveness ------------------------------------------------------------------------------------------ Physical inactivity 58.0 34.6 $11,313 per QALY + Hypertension 18.0 28.9 $25,000 per QALY & Smoking 25.5 25.0 $21,947 total lifetime benefits of quitting @ Obesity 23.0 32.1 NA** Elevated serum cholesterol (>=200 ug/dL) 37.0 42.7 $28,000 per QALY ++ ------------------------------------------------------------------------------------------ * Percentages cannot be summed because they are calculated independently for each risk factor. + Quality-adjusted life-years. & Source: Reference 9. @ Source: Reference 10. ** Not available. ++ Source: Reference 11. ============================================================================================ Return to top. Disclaimer All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices. **Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.Page converted: 09/19/98 |
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