Changes in energy balance and body composition at menopause: a controlled longitudinal study.

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 < or = 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.