This population-based longitudinal study examined whether duration of endogenous oestrogen exposure (EEE) is associated with the subsequent incidence of type 2 diabetes (T2D) in women. The authors state that the role of endogenous oestrogen exposure in T2D risk is understudied despite potential clinical importance. The primary objective was to assess T2D incidence across groups of women categorized by EEE duration and to quantify the association per standard-deviation increase in an EEE z-score.
At study initiation, 6,273 post-menarche women aged over 20 years were eligible. After applying exclusion criteria, the analytic cohort comprised 3,411 women, of whom 2,754 were premenopausal and 657 were menopausal at baseline. The mean age of participants was 39.3 years (standard deviation [SD] 12.5), and mean menarcheal age was 13.5 years (SD 1.5). During follow-up approximately two decades in length, 1,053 women (30.9%) developed diabetes; incidence was 29.7% (819 cases) among premenopausal women and 35.6% (234 cases) among menopausal women.
Each woman’s duration of endogenous oestrogen exposure (EEE) was determined at baseline. The source reports that EEE was converted to a z-score for use in regression models, allowing the association to be quantified per 1-SD increase in EEE. The article does not provide further methodological detail in the abstract about the exact formula for EEE calculation or whether adjustments were made for factors such as pregnancies, lactation, or exogenous hormone use; those details were not reported in the source abstract.
The primary outcome was incident T2D during follow-up. Time-to-event analyses used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for T2D by EEE z-score. Models included an age- and BMI-adjusted analysis and a fully adjusted model accounting for additional potential confounders. The abstract reports HRs per 1-SD increase in EEE z-score.
Overall, 1,053 of 3,411 women (30.9%) developed diabetes during follow-up. In the model adjusted for age and body mass index (BMI), a higher EEE z-score was inversely associated with incident T2D (HR 0.91; 95% CI 0.85–0.97). This indicates that each 1-SD increase in EEE z-score corresponded to an approximate 9% reduction in T2D risk. After full adjustment for potential confounders, the inverse association remained statistically significant (HR 0.90; 95% CI 0.84–0.96), consistent with roughly a 10% lower risk of T2D per 1-SD increment in EEE.
The study’s findings suggest that longer duration of endogenous oestrogen exposure may be associated with a lower risk of developing type 2 diabetes in women. The authors highlight the potential importance of reproductive history—such as timing of menarche and menopause—in risk assessment for T2D. The reported effect sizes are modest but statistically significant after adjustment for age, BMI, and other confounders reported in the abstract.
The abstract does not provide full methodological details about how EEE was computed, which covariates were included in the fully adjusted model, or the precise length and completeness of follow-up for all participants; those details are not reported in the source abstract. The report is a summary and lists references and MeSH terms that include estrogens, menarche, menopause, and follow-up studies. Readers seeking protocol specifics, sensitivity analyses, or subgroup results should consult the full article (DOI: 10.1002/edm2.70267) for complete methods and supplementary data.
If confirmed in other cohorts and with detailed exposure measurement, the observed inverse association between EEE duration and T2D incidence supports considering reproductive history when stratifying diabetes risk in women. The study underscores the need for further research to clarify mechanisms linking endogenous oestrogen exposure to glucose metabolism and to identify whether particular reproductive factors (timing of menarche, age at menopause, parity, lactation, or cumulative reproductive years) drive the association.
Clinicians should interpret these findings in the context of established T2D risk factors such as age, BMI, family history, lifestyle, and comorbidities. The abstract emphasizes an association but does not establish causation; additional details in the full text would be necessary to evaluate confounding, mediation, and potential clinical applications.