Age-Related Changes in Lipid Metabolism 1

Abstract

Studies of lipids and aging in man have been concerned almost exclusively with measurement of serum lipid levels. In recent years more attention has been directed toward the vehicle of the serum lipids, namely, the serum lipoproteins. In animals it has also been possible to study lipid synthesis and degradation in various tissues and, from these studies, to obtain some idea of lipid turnover and accumulation. The ensuing discussion will cover both of these aspects of lipid metabolism in aging.

In general, serum or plasma lipid levels rise with age, although there are conflicting data. Page et al. (1) studied a small group of men aged 20-91 years and found no pattern of increasing cholesterol levels with aging. Eck and Desbordes (2) found that average cholesterol levels rose from 146 ± 5 mg/dl in a group of 10 subjects aged 5- 15 years to 172 ± 16 mg/dl in 10 subjects aged 22-41 years; serum cholesterol levels in 10 subjects aged 60-81 years were 177 ± 16 mg/dl. These data suggested a sharp rise in cholesterol early in life and then a plateau. Kornerup (3), on the other hand, found no difference in cholesterol levels between men aged 1-14 years (202 mg/dl) and 19-46 years (203 mg/dl) but in a group aged 50-82 years the serum cholesterol levels had risen to 237 mg/dl.

Keys et al. (4) reported on cholesterol levels in over 2000 men aged 17-78 years and found a steady increase between the ages of 17 and 55 and a drop in the 60- to 78-year group (Table I). In 1970, Werner et al. (5) reported on serum cholesterol levels in men and women visitors to the 1968 San Francisco Health Fair.