Tho overall goal of this research is to define, through secular trend analysis, the role of dietary variables on changes in plasma cholesterol levels over time in the Framingham Cohort and Offspring/Spouse populations. Analyses will focus on nutrition variables thought to have a major role in plasma cholesterol regulation including: total and saturated fat intake; polyunsaturated and monounsaturated fats; and cholesterol. The multiple regression and Analysis of Covariance Technique will be used and potential confounding variables, such as age, weight, and kilocalorie intake, will be adjusted for in the analyses. Four separate data samples will be used: a) males for whom repeated measures of dietary intake and cholesterol levels exist from 1957-60 and 1966-69; b) independent samples (n-1300) of males from 1957-60 and 1966-69; c) independent samples of women (n-2200) from 1957-60 and 1984-88; and d) independent samples of men (n-2600 from 1966-69 and 1984-88. ANCOVA for independent samples will be used for data samples b to d. The proposed analyses should elucidate how dietary intake may contribute to changes in plasma cholesterol over time in the Framingham population.