The effects of age and body composition on circulating serum oestrogens and androstenedione after the menopause

Abstract

Circulating levels of estrone, estradiol and androstenedione were measured in 2 large groups of postmenopausal women, in one group the women were between 46 and 56 yr of age and in the 2nd, older group they were 70 yr of age. In addition the fat mass was calculated from the height, wt and age of the women. Serum concentrations of both estrogens did not change with age: the serum androstenedione concentration decreased significantly. A change in body composition included decreased height and increased fat mass in the older group. Serum concentrations of both estrogens correlated significantly with the fat mass and serum androstenedione as well as with each other. From the correlation analysis it may be concluded that the conversion rate of androstenedione to estrone, and of estrone to estradiol, increases with age, which presumably explains the unchanged concentrations of the circulating estrogens in relation to postmenopausal age, although the precursor decreases during the same period.