Serum Vitamin C, Retinol and Zeaxanthin Are Inversely Associated With Cataract in a North Indian Population

Abstract

Purpose:: To investigate associations of serum antioxidants with cataract in the Indian setting.

Methods:: People aged 50 years and over were identified from enumeration of the 50+ age group age in 11 randomly sampled villages from a rural district of Haryana, North India. Digitised images of cortical and posterior subcapsular opacities and photographs of nuclear opacities were graded using LOCS II (≥2 grade for any opacity or dense opacities that could not be graded were considered as cataract). A blood sample was taken and analysed for antioxidants. Potential confounders including tobacco use, alcohol drinking, biomass fuel use, and sunlight exposure were collected by interview. Survey logistic regression was used to investigate associations of tertiles of antioxidants with cataract.

Results:: Of 1443 people aged 50 years or above enumerated, 94% completed a questionnaire, 87 % attended an eye examination and 78% gave a blood sample. The prevalence of any cataract was high (73.5%), mostly nuclear or mixed cataracts. Antioxidant levels tended to be low especially vitamin C (12.96 µmol/l for men and 16.75 µmol/l for women). Vitamin C levels were significantly inversely associated with cataract. Odds ratios for the highest (>= 15 µmol/l) compared to the lowest (≤6.3 µmol/L) tertile were 0.58, (95% CI 0.47 - 0.72). Retinol and zeaxanthin were also associated with reduced odds of cataract for the highest compared to the lowest tertile.

Conclusions:: Our results in a population with high levels of cataract suggest the importance of vitamin C in lens protection

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • nutritional factors • cataract