The time of year may play a role in cholesterol testing. Researchers have discovered that cholesterol levels change with the seasons and are at the highest in the winter. Reporting recently in the Archives of Internal Medicine, the investigators found that seasonal variation in cholesterol may need to be factored in when creating guidelines for treating high cholesterol. Also, it may have a bearing on diagnosing high cholesterol in individual patients, including those who have a borderline level.
The findings were based on a study of >500 healthy participants whose cholesterol was tested repeatedly over the course of 1 year. The average cholesterol level was 222 mg/dL of blood (the study defined ≥240 mg/dL as high). The researchers, however, found that in men it tended to peak at an average of almost 4 mg higher in December. For women, cholesterol levels peaked at an average of ≥5.4 mg higher in January.