We read with interest the article by Ockene et al,1 reporting a seasonal variation in blood lipid levels in their cohort of subjects, with a peak in the winter and a trough in the summer. Although the observed changes had limited amplitude values (1.8% and 2.5% of the average cholesterol level, respectively), it is interesting that there was a higher relative increase (7% in men and 47% in women) in the number of subjects with cholesterol levels of 240 mg/dL (6.2 mmol/L) or greater, and about 22% more people had total cholesterol levels of 240 mg/dL (6.2 mmol/L) or greater in the winter than in the summer. Apart from the risk of possible misclassification of cholesterol status owing to seasonal variation and the consequent increase in expenses for treatment, this finding may be relevant for other kinds of considerations as well.
Manfredini R, Boari B. Seasonal Variation in Serum Cholesterol Levels: Another Piece in the Puzzle of the Winter Excess of Cardiovascular Deaths?. Arch Intern Med. 2004;164(22):2500-2509. doi:10.1001/archinte.164.22.2505-a