Metabolically healthy and unhealthy obesity and risk of vasomotor symptoms in premenopausal women: cross-sectional and cohort studies

Objective To examine the relationship between metabolically healthy and unhealthy obesity phenotypes and risk of vasomotor symptoms (VMS) in premenopausal women. Design Prospective cohort study. Setting Middle-aged women in a cohort based on regular health screening examinations. Population Premenopausal Korean women aged 42-52 years were recruited and were followed up for a median of 4.2 years. The cross-sectional and cohort studies comprised 4672 women and 2590 women without VMS at baseline, respectively. Methods Adiposity measures included body mass index (BMI), waist circumference and percentage body fat. Being metabolically healthy was defined as not having any metabolic syndrome components or a homeostasis model assessment of insulin resistance of 2.5 or more. Main outcomes measures VMS (hot flushes and night sweats) assessed using the questionnaire. Results All adiposity measures were positively associated with an increased risk of VMS in both cross-sectional and longitudinal studies. The multivariable-adjusted prevalence ratio (95% confidence interval [CI]) for VMS comparing percentage body fat of 35% or more with the reference was 1.47 (95% CI 1.14-1.90) in metabolically healthy women, and the corresponding prevalence ratio was 2.32 (95% CI 1.42-3.78) in metabolically unhealthy women (P-interaction = 0.334). The multivariable-adjusted hazard ratio for incident VMS comparing percentage body fat of 35% or more with the reference was 1.34 (95% CI 1.00-1.79) in metabolically healthy women, whereas the corresponding hazard ratio was 3.61 (95% CI 1.81-7.20) in metabolically unhealthy women (P-interaction = 0.036). The association between BMI, waist circumference and VMS did not significantly differ by metabolic health status. Conclusions Maintaining normal weight and being metabolically healthy may help to prevent VMS in premenopausal women.