Association between high natural background radiation and cataract subtypes in female residents of Karunagappally, Kerala, India.

Cataracts have reportedly been linked to radiation exposure. The goal of this study was to investigate the relationship between natural gamma-radiation exposure and the prevalence of cataracts among female inhabitants of Karunagappally, Kerala, India's high natural background radiation areas (HNBRA). From 2013 to 2014, a total of 840 women, whose lifetime natural radiation exposure had been estimated, underwent ophthalmic examinations and structured interviews. Five hundred and fifty women were from the control region (low- and medium dose areas), and 290 were from high natural background radiation area. The Lens Opacities Classification System was applied for grading cataracts. In the control region, 79 (14%) cortical, 10 (2%) posterior subcapsular and 24 (4%) nuclear cataracts were identified, whereas 54 (19%), 9 (3%) and 10 (4%) cases, respectively, were observed in high natural background radiation area. Cortical cataracts were significantly associated with cumulative radiation doses of 200 mGy or greater (odds ratio: 2.46; 95% confidence interval: 1.11-5.45) in logistic regression models adjusted for age, body mass index and family history of diabetes mellitus. After combining cortical and posterior subcapsular cataracts-subtypes more closely connected to radiation exposure-women exposed to more than 140 mGy in their lifetime, a reported threshold, exhibited a significantly increased risk (odds ratio: 1.25; 95% confidence interval: 1.00-1.56). The present study found a significant association between cortical and posterior subcapsular cataract prevalence and high natural background radiation exposure.