Body weight and fat mass across the menopausal transition: hormonal modulators

Background The role of the menopause in weight gain is an understudied yet important field, given the rising prevalence of obesity and its associated risk of disease. Objective To review the current evidence regarding the impact of the menopausal transition on changes in body composition and fat accrual in women and the hormonal mechanisms underlying the process. Methods A critical appraisal of the current literature by experts in the field. Results Menopause is associated with an overall increase in fat mass, which tends to accumulate around the waist. There is also a decrease in lean mass, particularly evident in the lower limbs. Reduced energy expenditure (EE) has been confirmed in parallel with increased food intake, the latter being more evident in experimental models. A prominent role has been found for the estrogen receptor (ER) alpha isoform in fat accrual. Human studies suggest a role for androgens in central fat accumulation and type 2 diabetes. FSH is a key factor in the process of fat accumulation, but only in rodents. Clinical studies suggest that these endocrine alterations are insufficient to explain the observed changes. Conclusions The menopausal transition is associated with an increase in adiposity, which accumulates preferentially in the abdominal area. Hypoestrogenism and the imbalance of the androgen/estrogen ratio are strong candidates to explain the phenomenon, although other hormonal factors probably also play a role. The impact on risk of disease is still insufficiently known, although an association with risk factors, such as an unfavorable lipid profile or insulin resistance seems likely.