Associations between plasma levels of vitamins and cataract in the Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS): CTNS Report #2

Ophthalmic Epidemiol. 2005 Apr;12(2):71-80. doi: 10.1080/09286580590932815.


Purpose: To investigate the association at baseline between plasma levels of selected vitamins and the presence and type of cataract in the participants in The Italian-American Trial of Nutritional Supplements and Age-related Cataract.

Methods: At baseline, the participants (1020, 710 with "early cataract" and 310 with "no cataract," 55-75 years of age) received an ocular examination, photographic lens grading, and measurement of plasma levels of vitamins A, C, E, beta-carotene, and of red blood cell glutathione reductase activity.

Results: In multiple logistic models adjusted for potential confounders, high vitamin C levels were associated with a protective effect on nuclear (N) [OR: 0.54; 95% CI: 0.30, 0.97] and posterior subcapsular (PSC) cataract (OR: 0.37; 95% CI: 0.15, 0.93). High vitamin E levels were associated with increased prevalence of cortical cataract (C) (OR: 1.99; 95% CI: 1.02-3.90), PSC (OR: 3.27; 95% CI: 1.34, 7.96) and of any cataract (OR: 1.86; 95% CI: 1.08, 3.18).

Conclusions: In agreement with some earlier studies, we found higher plasma levels of vitamin C to be associated with reduced prevalence of N and PSC cataracts. The finding of an increased prevalence of some types of cataract with higher levels of vitamin E was unexpected, has not been previously reported, and could be due to unadjusted confounding.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Aging*
  • Ascorbic Acid / blood*
  • Cataract / blood
  • Cataract / classification
  • Cataract / epidemiology*
  • Chromatography, High Pressure Liquid
  • Dietary Supplements*
  • Erythrocyte Membrane / enzymology
  • Female
  • Glutathione Reductase / analysis
  • Humans
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Prevalence
  • Quality Control
  • United States / epidemiology
  • Vitamin A / blood*
  • Vitamin E / blood*
  • beta Carotene / blood*


  • beta Carotene
  • Vitamin A
  • Vitamin E
  • Glutathione Reductase
  • Ascorbic Acid