Changes in Energy Balance and Body Composition at Menopause: A Controlled Longitudinal Study

Abstract

Objective: To describe the effects of menopause on resting metabolic rate, body composition, fat distribution, physical activity during leisure time, and fasting insulin levels.

Design: A longitudinal comparison of metabolic changes in women who experienced menopause with changes in age-matched women who did not experience menopause.

Setting: General clinical research center.

Patients: An initial cohort of 35 sedentary healthy premenopausal women (age range, 44 to 48 years). After 6 years of follow-up, 18 women had spontaneously stopped menstruating for at least 12 months and 17 women remained premenopausal. No women received hormone replacement therapy.

Results: Women who experienced menopause lost more fat-free mass than women who remained premenopausal (−3.0 ± 1.1 kg and −0.5 ± 0.5 kg, respectively), had greater decreases in resting metabolic rate (−103 ± 55 kcal/d and −8 ± 17 kcal/d) and physical activity during leisure time (−127 ± 79 kcal/d and 64 ± 60 kcal/d), and had greater increases in fat mass (2.5 ± 2 kg and 1.0 ± 1.5 kg), fasting insulin levels (11 ± 9 pmol/L and −2 ± 5 pmol/L), and waist-to-hip ratios (0.04 ± 0.01 and 0.01 ± 0.01) (P ≤ 0.01 for all comparisons). Menopause did not affect energy intake, fasting glucose levels, or peak oxygen consumption.

Conclusions: Natural menopause is associated with reduced energy expenditure during rest and physical activity, an accelerated loss of fat-free mass, and increased central adiposity and fasting insulin levels. These changes may indicate a worsening cardiovascular and metabolic risk profile.