Body mass index is not associated with early onset cataract in the 45 and Up cohort study

Background: Body mass index (BMI) has been reported to be associated with age-related cataract, whereas its impact on early onset cataract (EOC) remains unknown. Methods: A total of 73,007 individuals aged 45-55 years who had no previous cataract surgeries at baseline were enrolled from the population-based 45 and Up Study. BMI was calculated based on self-reported height and weight from the baseline questionnaire. Data on cataract surgeries were obtained from the Medicare Benefits Schedule database. EOC was defined as cataract surgically treated prior to 65 years of age. A Cox proportional hazards regression was used to assess the association between BMI and the incidence of EOC during the follow-up. Results: A total of 1,764 participants underwent cataract surgery over 643,717 person-years of followup. No significant association was observed between BMI and EOC (P for trend 0.35). Among participants who drank 5 to 7 alcoholic drinks per week, a 73% and 27% reduction in the risk of EOC was observed in participants with a BMI of 18.5-19.99 kg/m(2) and 25.0-27.49 kg/m(2), respectively, compared to those with a BMI of 20.0-22.49 kg/m(2). Conclusions: No association was identified between BMI and the incidence of EOC. Moderate alcohol intake may be protective against EOC.