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.
OBJECTIVE
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.
Ferrigno
L
L
Centro Nazionale di Epidemiologia, Sorveglianza e Promozione della Salute, ISS, Rome, Italy.
Aldigeri
R
R
Rosmini
F
F
Sperduto
R D
RD
Maraini
G
G
D000368:Aged; D000375:Aging; D001205:Ascorbic Acid / Q000097:blood*; D002386:Cataract / Q000097:blood / Q000145:classification / Q000453:epidemiology*; D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements; D004910:Erythrocyte Membrane / Q000201:enzymology; D005260:Female; D005980:Glutathione Reductase / Q000032:analysis; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011786:Quality Control; D014481:United States / Q000453:epidemiology; D014801:Vitamin A / Q000097:blood*; D014810:Vitamin E / Q000097:blood*; D019207:beta Carotene / Q000097:blood*
D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D005980:Glutathione Reductase; D001205:Ascorbic Acid