Trends in plasma cholesterol levels in the Atherosclerosis Risk in Communities (ARIC) study

Background. Data from the Atherosclerosis Risk in communities (ARIC) cohort study were examined both cross-sectionally and intraindividually to confir m recent findings from population-based studies showing a decline in total cholesterol CTC) levels in the United States. Methods, For the cross-sectional analysis, mean plasma TC levels from 15,79 2 participants aged 45-64 at baseline visit, and who were selected randomly from four U.S. communities, were examined for each year covered by the fir st cohort visit (1987, 1988, and 1989). Ninety-three percent of the cohort participants returned for the follow-up visit (1990, 1991, and 1992), and w ere included in the assessment of intraindividual TC trends. Results, Both mean TC and prevalence of hypercholesterolemia (defined as pl asma cholesterol concentration greater than or equal to 240 mg/dl) consiste ntly declined over the 3 years covered by visit 1 for all age-gender-race g roups. For 1987, 1988, and 1989, mean TC values (mg/dl) were, respectively, 220.3, 216.7 and 214.1 (annual average change, -1.4%, P < 0.001). For thes e same years, hyper-cholesterolemia prevalence rates were 30.0, 27.8, and 2 5.3% (annual average change, -7.8%, P < 0.001). The mean plasma TC also dec reased Within individuals between the two visits across race, gender, and a ge decade categories. With the exception of black men, this decline was mor e marked for older than younger subjects, but no consistent differences wer e seen between the racial groups. However, in whites, decreases were greate r for men than for women. Expected results were seen when these changes wer e correlated with changes in cardiovascular risk factors between the two vi sits. Conclusion. The current study results are consistent with those of previous studies, and confirm the notion that preventive programs appear to be effe ctive in reducing mean population TC levels. (C) 2000 American Health Found ation and Academic Press.