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DAY-TO-DAY FLUCTUATIONS IN SERUM CHOLESTEROL.

The growth of cholesterol screening programs has triggered renewed interest in day-to-day variability in serum cholesterol levels. Two reports now suggest that much of this variability is independent of laboratory factors. Mogadam and colleagues drew weekly fasting serum samples from 20 subjects over a 4-week period. Each sample was sent for lipid analysis to two different laboratories and run five times in each lab. Bookstein and colleagues analyzed three serum samples drawn over 5 days from each of 51 subjects, and sent random samples to the Centers for Disease Control to confirm accuracy.

Taken together, these studies demonstrate several points. First, there was substantial day-to-day variability in total cholesterol. For example, 80 percent of Mogadam's subjects had fluctuations in excess of 30 mg/dl, and 25 percent had fluctuations exceeding 50 mg/dl. Second, most fluctuations reflected true biologic variability; variability due to laboratory factors never exceeded 3 percent for total cholesterol. Finally, in patients with a mean total cholesterol of 185 to 255 mg/dl, there was a considerable chance that a single value would be sufficiently far from the mean to change the patient's risk category (as defined by National Cholesterol Education Program guidelines). These studies document considerable natural fluctuations in serum cholesterol. The cardiovascular risk attributed to cholesterol may be significantly over- or underestimated unless multiple measurements are made.

— ASB

Published in Journal Watch General Medicine August 28, 1990

Citation(s):

Bookstein L et al. Day-to-day variability of serum cholesterol, triglyceride, and high-density lipoprotein cholesterol levels. Arch Intern Med 1990 Aug 150 1653-1657.

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Mogadam M et al. Within-person fluctuations of serum cholesterol and lipoproteins. Arch Intern Med 1990 Aug 150 1645-1648.

• Medline abstract (Free)