Endogenous estrogen exposure and chronic kidney disease; A 15-year prospective cohort study

Background: Despite strong evidence demonstrating the role of estrogen as a protective factor for kidney function in women, limited data are available regarding the influence of endogenous estrogen exposure (EEE) on chronic kidney disease (CKD). The present study aimed to assess the incidence of CKD in women with various levels of EEE. Methods: : In a prospective population-based study over a 15-year follow-up, a total of 3043 eligible women aged 30-70 years, participating in Tehran-Lipid and Glucose-Study were recruited and divided in two groups(EEE <11 and EEE≥11 years). Cox’s proportional hazards model was applied to estimate the hazard ratio of CKD between the study groups, after adjusting for confounders. Results: : The total cumulative incidence rate of CKD at the median follow-up time of approximately 15.6 years was 50.1 per 1000 person years; 95% CI: 47.7–52.6); this was 53.9 per 1000 person years (CI, 50.2–57.8) and 47.1 per 1000 person years (CI, 44.0–50.4) in women with EEE<11 and EEE≥ 11 years, respectively. The multivariate Cox model adjusted for age, BMI, smoking, hypertension and diabetes showed that the HR of developing CKD in women with EEE<11 years was significantly higher than in those with ≥ 11 years (HR: 4.0; 95% CI: 2.5, 6.3). Conclusion: This study shows a higher hazard ratio of CKD progression in women with low EEE levels in their later life. Our results suggest that the early diagnosis and management of subsequent kidney diseases in these women may potentially prevent the complications of this disease.