Association of Sex With the Global Burden of Cataract

Abstract

Eye disease burden could help guide health policy making. Differences in cataract burden by sex is a major concern of reducing avoidable blindness caused by cataract. To investigate the association of sex with the global burden of cataract by year, age, and socioeconomic status using disability-adjusted life-years (DALYs). This international, comparative burden-of-disease study extracted the global, regional, and national sex-specific DALY numbers, crude DALY rates, and age-standardized DALY rates caused by cataract by year and age from the Global Burden of Disease Study 2015. The DALY data were collected from January 1, 1990, through December 31, 2015, for ever 5 years. The human development index (HDI) in 2015 was extracted as an indicator of national socioeconomic status from the Human Development Report. Comparisons of sex-specific DALY estimates due to cataract by year, age, and socioeconomic status at the global level. Paired Wilcoxon signed rank test, Pearson correlation, and linear regression analyses were performed to evaluate the socioeconomic-associated sex differences in cataract burden. Differences in rates of cataract by sex were similar between 1990 and 2015, with age-standardized DALY rates of 54.5 among men vs 65.0 among women in 1990 and 52.3 among men vs 67.0 among women in 2015. Women had higher rates than men of the same age, and sexual differences increased with age. Paired Wilcoxon signed rank test revealed that age-standardized DALY rates among women were higher than those among men for each HDI-based country group (z range, -4.236 to -6.093; P < .001). The difference (female minus male) in age-standardized DALY rates (r = -0.610 [P < .001]; standardized β = -0.610 [P < .001]) and the female to male age-standardized DALY rate ratios (r = -0.180 [P = .02]; standardized β = -0.180 [P = .02]) were inversely correlated with HDI. Although global cataract health care is progressing, sexual differences in cataract burden showed little improvement in the past few decades. Worldwide, women have a higher cataract burden than men. Older age and lower socioeconomic status are associated with greater differences in rates of cataract by sex. Our findings may enhance public awareness of sexual differences in global cataract burden and emphasize the importance of making sex-sensitive health policy to manage global vision loss caused by cataract.