Associations Among Outdoor Time, Skin Tanning, and the Risk of Surgically Treated Cataract for Australians 45 to 65 Years of Age

PURPOSE: To investigate the association between outdoor time and the risk of cataract surgery in a large Australian population. METHODS: This was a population-based prospective cohort study with 137,133 participants 45 to 65 years of age and without prior history of cataract surgery from the 45 and Up Study. Outdoor hours per day on weekdays and weekends, as well as tanning with repeated sun exposure, were assessed by a self-administered baseline questionnaire. Cataract surgery events were confirmed by the Medicare Benefits Schedule from baseline until the end of follow-up in 2016. RESULTS: During a mean follow-up of 9 years, 14,338 participants received cataract surgery with a corresponding incidence of 10.5%. Multiple Cox regression analysis showed that more outdoor hours on weekends (P trend < 0.001) and the ability to get tanned by repeated sun exposure (P trend = 0.041) were significantly associated with a lower risk of cataract surgery, whereas more outdoor hours on weekdays were nominally significantly associated (P trend = 0.055). Participants who spent 10+ hours outdoors on weekends had 9% decreased risk compared with those who spent ≤2 hours outdoors. In addition, compared to participants who got very tanned by repeated sun exposure, those less likely to get tanned had a 5% to 7% increased risk of cataract surgery. CONCLUSIONS: In this large Australian cohort 45 to 65 years of age, more outdoor time and ease of tanning with sun exposure were associated with a lower incidence of cataract surgery. TRANSLATIONAL RELEVANCE: With proper sun protection, more outdoor time may lead to a lower risk of severe cataracts requiring surgery.