Parity and the risk of cataract: a cross-sectional analysis in the Dongfeng-Tongji cohort study

Aims Epidemiological evidence showed that prevalence rates of cataract were higher in women than in men. Female reproductive factors were hypothesised to be linked with this sex difference. In this study, we explored possible effects of parity and reproductive factors on the risk of cataract. Methods Women (14 337 total; aged 45-86 years) were recruited from the Dongfeng-Tongji cohort study. All subjects completed baseline questionnaires and medical examinations and provided baseline blood samples. Cataract was diagnosed by the ophthalmologist in the ocular examination. Logistic regression models were used to evaluate the association between parity and the risk of cataract. Results The prevalence rate of cataract in the study population was 6.8% (972/14 337). After adjustment for potential confounders, women who had undergone two, three, and four or more live births had 1.52 times (95% CI 1.13 to 2.04), 1.67 times (95% CI 1.27 to 2.29) and 1.72 times (95% CI 1.22 to 2.42), respectively, higher risk of cataract compared with women who had undergone one live birth. The risk increased by an estimated 11.3% for each additional live birth. Women who had undergone hormone replacement therapy (OR 1.61; 95% CI 1.05 to 2.47), had diabetes mellitus (OR 1.33; 95% CI 1.11 to 1.58) and/or had the habit of drinking alcohol (OR 1.51; 95% CI 1.08 to 2.10) had a higher risk of cataract. Neither menopause status nor history of contraceptive use was associated with cataract. Conclusions The findings suggested that parity was an independent risk factor for the development of cataract in Chinese women.