Relative Importance of Borderline and Elevated Levels of Coronary Heart Disease Risk Factors

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Abstract
Clinical trials indicate that a sizable proportion of adults have multiple borderline coronary risk factors and may benefit from treatment. To estimate the relative and absolute contributions of borderline and elevated risk factors to the population burden of coronary heart disease (CHD) events. A prospective cohort study and a national cross-sectional survey. The Framingham Study and the Third National Health and Nutrition Examination Survey (NHANES III). White non-Hispanic persons in the Framingham Study and in NHANES III who were between 35 to 74 years of age and had no CHD. Occurrence of first CHD events according to 5 major CHD risk factors: blood pressure, low-density lipoprotein and high-density lipoprotein cholesterol levels, glucose intolerance, and smoking. Three categories—optimal, borderline, and elevated—were defined for each risk factor per national guidelines. Sex-specific 10-year CHD event rates from the Framingham Study were applied to numbers of at-risk individuals estimated from NHANES III and the 2000 U.S. Census. Twenty-six percent of men and 41% of women had at least 1 borderline risk factor in NHANES III. According to estimates, more than 90% of CHD events will occur in individuals with at least 1 elevated risk factor, and approximately 8% will occur in people with only borderline levels of multiple risk factors. Absolute 10-year CHD risk exceeded 10% in men older than age 45 years who had 1 elevated risk factor and 4 or more borderline risk factors and in those who had at least 2 elevated risk factors. In women, absolute CHD risk exceeded 10% only in those older than age 55 years who had at least 3 elevated risk factors. The generalizability of the findings to persons of other ethnic backgrounds is unknown. Borderline CHD risk factors alone account for a small proportion of CHD events.