Timing of first childbirth and age-related cataract

Objective: No studies investigated the effects of age at first childbirth on cataract formation. This study was performed to determine the relationships of age at first childbirth to age-related cataract in postmenopausal women. Methods: Study population included 7,021 postmenopausal women in the Korea National Health and Nutrition Examination Survey, 2008 to 2012. Participants were subdivided in quartiles according to the age at first childbirth as follows: 13 to 21, 22 to 23, 24 to 25, and 26 to 44 years. We used odds ratios (ORs) and 95% confidence intervals (CIs) to address the relationships between age at first childbirth and age-related cataract with adjustments for confounders. Results: Mean participants' age and age at first childbirth were 64.4 and 23.6 years, respectively. The prevalence of any subtype of age-related cataract was 64.9%. Nuclear cataract prevalence was significantly higher in postmenopausal women with later age at first childbirth (24-25 and 26-44 years) compared with those with the earliest age at first childbirth (13-21 years): ORs (95% CIs) were 1.23 (1.05-1.45) and 1.24 (1.05-1.46), respectively. A significant linear trend across quintile was observed (P=0.006). Age at first childbirth linearly 4% (OR 1.04, 95% CI 1.01-1.06) and 2% (OR 1.02, 95% CI 1.00-1.04) increased risk for nuclear and cortical cataract formation, respectively. The population-attributable fraction of nuclear cataract caused by the first childbirth at 24 years or later was 4.9% (95% CI 1.20%-8.59%, P=0.009). Conclusions: Later age of first childbirth was independently associated with higher risks of nuclear and cortical cataract in postmenopausal women. Further prospective studies are needed to elucidate the role of age at first childbirth in developing age-related cataract.