Exploring the link between age at menarche, anthropometry and body fat composition with type II diabetes in a Singapore multi-ethnic cohort.

Background: Early menarche is associated with lifelong health implications, including heightened risks for obesity, type 2 diabetes (T2D), cardiovascular disease, and overall mortality. This study explored the associations that link early menarche, major adiposity indices, and T2D in a group of multi-ethnic Asian women.

Methods: A prospective, hospital-based study was conducted in Singapore. Two thousand seven hundred fifteen women were recruited from 2014 to 2016 (45-69 years old) and 1201 women were followed up from 2021 to 2023. At baseline, age at menarche (AAM) was divided into sub-categories: < 12 (early AAM), 12-13, 14-15 (reference), > 15 years. Major adiposity indices and glycemic profiles were assessed, including fat mass index (FMI), visceral adipose tissue (VAT), and HOMA-IR (homeostatic model assessment for insulin resistance). At the 6.6-year follow-up, T2D was assessed. One-way ANOVA and chi-square were performed for continuous and categorical variables, respectively. Multivariable regression analysis was performed to determine the association between AAM and primary outcomes, including adiposity measurements (FMI, VAT) and metabolic assessments (HOMA-IR) at baseline. Modified Poisson regression was performed to assess relative risk (RR) between AAM and T2D at follow-up. Serial mediation analysis was performed to determine potential mediators underlying the link between AAM and T2D. All analyses accounted for major confounders including age, ethnicity, and education.

Results: Women with early AAM had significantly greater values in adiposity assessments, including increments in FMI (10.9 vs 10.3, p < 0.001), VAT (134 vs 113 cm, p = 0.05) and HOMA-IR (1.20 vs 1.03, p = 0.08) at baseline. Early AAM (< 12 vs. 14-15 years) was associated with a 60% increased risk of developing T2D (RR 1.60 (95%CI: 1.04, 2.45)). Serial mediation analysis suggested a significant pathway underlying early AAM and T2D, which was firstly mediated by FMI, followed by VAT and lastly by HOMA-IR (p < 0.05).

Conclusions: Our study provided valuable insight into the pathophysiology of T2D development amongst mid-life women with early AAM. The findings could potentially indicate strategies to target FMI and VAT among Asian women in the menopausal phase with early AAM, to prevent the development of T2D.