Multiple regression was used to assess the effect of dietary variables on changes in serum cholesterol between 1957-1960 and 1966-1969 in a sample of 200 men for whom repeated measurements existed in the Framingham cohort. Analysis of covariance was used to assess influence of dietary intake on differences in serum cholesterol levels between independent samples of men studied in 1957-1960 and 1966-1969 in the Framingham cohort, and independent samples of women studied between 1957-1960 and 1984-1988 in the Framingham cohort and Offspring cohort, and independent samples of men studied between 1966-1969 and 1984-1988 in the Framingham cohort and Offspring cohorts respectively.