Change in body weight after hormone replacement therapy in postmenopausal women is dependent on basal circulating...

To address the effect of leptin in the modulation of change in body weight after hormone replacement therapy (HRT), we prospectively examined the responses of body weight and serum leptin after estrogen-progestin replacement in postmenopausal women.

Subjects consisted of 63 postmenopausal women aged 54-82 years on HRT for osteoporosis.

Thirty three of the subjects received 0.3 mg of conjugated equine estrogen (CEE) (group 1) while 30 were on 0.625 mg of CEE daily (group 2). All subjects also took 5 mg of medrogestone acetate and 750 mg elemental calcium supplement daily.

Fasting serum leptin was measured by RIA at baseline, 1 and 3 months after treatment. Data were expressed as mean +/- S.E.M.

Serum leptin was highly related to body weight both at baseline (r = 0.40, P < 0.001) and after 3 months of HRT (r = 0.42, P < 0.001). When divided the subjects into three equal groups according to baseline leptin levels, it was found that serum leptin significantly decreased in subjects with high baseline leptin at 3 months (-9.4 +/- 5.7%, P < 0.05) while it increased in subjects whose baseline leptin levels were in the lowest tertile at 1 month (33.2 +/- 8.3%, P < 0.001) and 3 month (27.8 +/- 8.3%, P < 0.01). In regards to body weight, those with leptin in the highest tertile demonstrated a reduction of body weight at 3 (-1.9 +/- 0.6%, P < 0.05) and 12 months (-3.2 +/- 0.5%, P < 0.05) after HRT while those whose serum leptin levels were in the lowest and middle tertiles did not demonstrate change in body weight. By repeated measured analysis of variance, it was found that the decrease in body weight in subjects with high serum leptin was independent of the doses of estrogen.

Postmenopausal hormone replacement does not cause weight gain. However, it results in a small reduction in body weight particularly in subjects with higher basal leptin concentrations.