Prospective study of type 2 diabetes mellitus and risk of primary open-angle glaucoma in women

Purpose: To study the relation between type 2 diabetes mellitus (T2DM) and incident primary open-angle glaucoma (POAG) in women. Design: Prospective cohort analysis. Participants: Seventy-six thousand three hundred eighteen women enrolled in the Nurses' Health Study (NHS). Methods: Women enrolled in the NHS from 1980 to 2000 were observed. Eligible participants were at least 40 years old, did not have POAG at baseline, and reported receiving eye examinations during follow-up. Potential confounders were assessed on biennial questionnaires, and a diagnosis of T2DM was confirmed on a validated supplemental questionnaire. During follow-up, 429 self-reported POAG cases confirmed by medical chart review were identified. Main Outcome Measures: Multivariable rate ratios (RRs) of POAG and associated 95% confidence intervals (CIs) obtained from proportional hazards models. Results: After controlling for age, race, hypertension, body mass index, physical activity, alcohol intake, smoking, and family history of glaucoma, T2DM was positively associated with POAG (RR = 1.82 [95% CI = 1.23-2.70]). Nonetheless, the association did not strengthen with longer duration of diabetes: RR = 2.24 (95% CI = 1.31-3.84) for duration < 5 years versus RR = 1.54 (95% CI = 0.90-2.62) for duration >= 5 years). In secondary analyses, to evaluate the potential for detection bias we controlled for additional factors such as the number of eye examinations, but T2DM remained positively associated with POAG. Conclusion: Type 2 diabetes mellitus is associated with an increased risk of POAG in women.