Obesity indicators as mediators of the association between age at menopause and blood pressure values

Having a later age at menopause is associated with having a higher blood pressure (BP) value, but the mediation pathways remain unclear. We quantitatively examined the mediation effects of various obesity indicators using baseline data from phase 4 of the Guangzhou Biobank Cohort Study. The product of coefficients approach and bootstrapping procedures were used to assess the mediation effects of body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) on the association between age at menopause and BP values. Age, education, occupation, family income, smoking, drinking, diet, physical activity, age at menarche, number of births, fasting glucose, triglycerides, and high-density lipoprotein cholesterol were adjusted as covariates. Of 5429 women with natural menopause, the mean age and menopausal age were 60.0 (standard deviation = 5.8) and 50.3 (3.1) years, respectively. The prevalence of hypertension was 29.6%. In women with a menopausal age of >= 50 years, BMI, WC, WHR and WHtR showed significant mediation effects on the positive association between menopausal age and BP. The adjusted proportion (95% confidence interval) of the mediation effects for those variables were 26.04% (10.40-116.82%), 25.92% (10.19-108.57%), 14.11% (3.59-62.78%), and 23.17% (8.70-95.81%), respectively, for systolic BP values and 22.59% (10.72-53.60%), 20.67% (9.83-49.31%), 9.21% (2.73-23.92%), and 17.19% (7.56-41.31%) for diastolic BP values. In women with a menopausal age of < 50 years, no significant association between age at menopause and systolic/diastolic BP values was found. In conclusion, obesity indicators showed significant mediating effects on the association between having a later age at menopause and having a higher BP value. Further longitudinal studies with detailed and accurate measurements of metabolic changes after menopause and sufficient follow-up are warranted to confirm these results.