Relationships of Macular Pigment Optical Density (MPOD) to Cataract Extraction in the Second Carotenoids in Age-Related Eye Disease Study (CAREDS 2), an ancillary study of the Women's Health Initiative (WHI) Observational Study

Abstract

Purpose : Concentrations of lutein (L) and zeaxanthin (Z), in the central retina are correlated with those in the lens epithelium, where they also selectively accumulate and have been observed to protect against damage due to UV light and oxidative stress, otherwise thought to promote cataract development. We assessed whether higher MP optical density (MPOD) is associated with lower incidence of cataract extraction.

Methods : Baseline MPOD at 0.5 degrees (relative to a reference of 7 degrees) was determined at CAREDS study visits (2001-2004) using heterochromatic flicker photometry in 1804 women 55-84 years of age. A total of 959 women (free of cataract extraction and eye trauma at baseline) who were not lost to follow-up in the WHI were included; 774 of whom survived during the follow-up period. Incident cataract extraction was reported in 407 women (53%), in WHI extension II questionnaires (year 4: 2013-2014). Several previous studies indicate higher risk of death in individuals with cataracts. To evaluate the potential impact of the competing risk of death on the relationships of MPOD to cataract extraction, we also investigated the relationship of MPOD to the combined outcome of cataract extraction and death over the same time period.

Results : There was a trend for reduced risk of cataract extraction in women in the highest, vs. lowest MPOD quintile (OR (95% confidence interval) = 0.61 (0.37, 1.01) P for Trend = 0.09, after adjustment for age, and 0.62 (0.37, 1.03) after further adjustment for hormone therapy, smoking, and heavy alcohol intake. The associations were not attenuated by further adjustment for shared risk factors for low MPOD and cataract (obesity, diabetes, and low healthy eating index): OR (95%CI) = 0.58 (0.34, 1.00)). The age- adjusted OR (95%CI) for the combined outcome of cataract extraction and mortality among women in high vs. low MPOD quintiles was: (0.50 (0.31, 0.81); P Trend = 0.01), which reduced to (0.53 (0.32, 0.89; P Trend = 0.04), after adjustment for the same potential confounders and shared risk factors.

Conclusions : There was a protective trend for low risk of cataract extraction among women with high MPOD, which may be underestimated by the competing risk of mortality in women with low MPOD.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.