Clarifying the Direct Relation between Total Cholesterol Levels and Death from Coronary Heart Disease in Older Persons

BACKGROUND: The importance of total cholesterol level as a risk factor for coronary heart disease in older adults is controversial. OBJECTIVE: To determine whether findings showing that total cholesterol level is not an important risk factor for coronary heart disease in older adults are the result of inadequate adjustment for co-occurring diseases and frailty. DESIGN: Multicenter, longitudinal study with 5-year follow-up for death. PARTICIPANTS: 4066 men and women from East Boston, Massachusetts; Iowa and Washington counties, Iowa; and New Haven, Connecticut. MEASUREMENTS: In 1988, participants were interviewed about their health status and had blood samples taken. Mortality follow-up was through 1992. RESULTS: In analyses that included all fatal coronary heart disease events (252 deaths) and did not adjust for risk factors for coronary heart disease and measures of frailty, persons with the lowest total cholesterol levels ( or = 6.20 mmol/L > or = 240 mg/dL) seemed to have a lower risk for death from coronary heart disease (P for trend = 0.04). After adjustment for established risk factors for coronary heart disease and markers of poor health (including chronic conditions, low serum iron and albumin levels) and exclusion of 44 deaths from coronary heart disease that occurred within the first year, elevated total cholesterol levels predicted increased risk for death from coronary heart disease, and the risk for death from coronary heart disease decreased as cholesterol levels decreased (P for trend = 0.005). CONCLUSIONS: Elevated total cholesterol level is a risk factor for death from coronary heart disease in older adults, and the apparent adverse effects associated with low cholesterol levels are secondary to comorbidity and frailty. This suggests that excluding older persons from cholesterol screening is inappropriate, but interpretation of screening results in older persons requires clinical judgment. Results from controlled clinical trials are needed to clarify this issue.