Observations on seasonal variations in total serum cholesterol level among healthy young prisoners

T H E total serum cholesterol level in a given individual at any particular point in time is the result of numerous technical and biologic variables.1"5 § Many different methods of chemical analysis of the total cholesterol content of blood serum have been described and compared, both in terms of absolute values and of reproducibility; the technical aspects of cholesterol variability, however, do not concern us here. The biologic factors which influence the level of cholesterol are of even greater diversity and importance. The effects of age, sex, heredity, and diet have been well documented. In con-trast, scant attention has been paid to the possibility of seasonal variations in cholesterol level.6 Our interest in seasonal fluctuations in cholesterol level stems from a long-term study of the precursors of hypertension and coronary artery dis-ease using Johns Hopkins medical students as subjects.6 In the course of the study, the effects of a number of factors on cholesterol level have been explored, and repeated determinations have been made on individual sub