More from Framingham
More from Framingham
ABSTRACT & COMMENTARY
Synopsis: The new Framingham analysis provides a model to assess the cumulative and lifetime risk of developing coronary heart disease for men and women.
Source: Lloyd-Jones DM, et al. Lancet 1999;353:89-92.
A novel approach to understanding the risk of developing coronary heart disease (CHD) has been proposed by the Framingham Heart Study, which has continued for 50 years. The present Framingham program has created a model to assess the cumulative and lifetime risk of developing CHD for men and women. This approach uses the Framingham database, derived from the original cohort of 5200 (free from heart disease and enrolled in 1948), as well as another 5100 offspring enrolled in 1971. A total of 7732 participants, aged 40-94 years, without a history of coronary disease, were included in the analysis. All deaths were coded for six mutually exclusive causes, including CHD, stroke, and cancer. In addition, CHD events were categorized. Careful statistical analysis was used to calculate the lifetime risk of development of CHD. Follow-up was concluded in 1996, the year of the first CHD event, death, or age 95. A total of 10,000 person years were accumulated during follow-up; 1057 subjects developed CHD and another 1312 died from noncoronary causes. The main analysis is as follows: the risks of developing CHD for the entire cohort was age-dependent for both men and women. (See Table.) Thus, for individuals at age 40, there is a 50% lifetime risk of CHD for men and 32% for women. As the cohorts continued to be free from CHD, the lifetime risk for a first event decreases. At age 70, the lifetime CHD risk is still as high as 1 in 3 for men and 1 in 4 for women. Men demonstrated a higher short-term risk of CHD as well as a higher lifetime risk than women at all ages. The risk curves for individuals older than 60 rise steeply in men and women. This lifetime risk approach has been used for breast cancer and several other diseases. This analysis did not directly evaluate significant CHD risk factors, such as hypertension or hypercholesterolemia; including these would clearly result in worse CHD risk prediction than the average subject. Lloyd-Jones and colleagues conclude that this new Framingham analysis "provides a rationale for screening and treatment of hypertension and hypocholesterolemia in older and younger patients."
| Table | ||
| Lifetime Cumulative Risk of Developing CHD__ | ||
| Age |
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| 40 |
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| 50 |
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| 60 |
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| 70 |
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Comment by Jonathan Abrams, MD
These data should be instructive for physicians and patients. The steep rise in the risk curves graphically demonstrates the burden of vascular disease with age; the good news is that as one lives longer without having a coronary event, the remaining lifetime risk for developing overt CHD is less than at an earlier age. Adding CHD risk factors to these curves (or the absence of CHD risk) can clarify what one’s future likelihood is for CHD when counseling a patient or embarking upon prevention programs. One main limitation of the Framingham data, as pointed out by Lloyd-Jones et al and an accompanying editorial, is the uniform ethnic identity of the Framingham population, which is predominantly white from a single town, with presumably common genetic and environmental factors operating. Thus, extrapolation of these findings to other populations may be problematic. Furthermore, new therapies for CHD could alter these estimates. Nevertheless, I believe this is a useful construct that should help all those interested in assessment of CHD risk.
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