Clinical Question:
Is a high dietary intake of beta carotene, vitamins C and E, and zinc
associated with a reduced risk of age-related macular degeneration?
Bottom Line:
A high dietary intake of beta carotene, vitamins C and E, and zinc reduces
the risk of age-related macular degeneration (AMD).
Reference:
van Leeuwen R, Boekhoorn S, Vingerling JR, et al. Dietary intake of
antioxidants and risk of age-related macular degeneration. JAMA
2005;294:3101-07.
Study Design:
Cohort (prospective)
Synopsis:
Age-related macular degeneration (AMD) is the most prevalent cause of
irreversible blindness in developed countries. Recently, high-dose
supplementation with beta carotene, vitamins C and E, and zinc was shown to
slow the progression of AMD. To investigate whether regular dietary intake
of antioxidants is associated with a lower risk of incident AMD. Dietary
intake was assessed at baseline in the Rotterdam Study (1990-1993) using a
semiquantitative food frequency questionnaire. Incident AMD until final
follow-up in 2004 was determined by grading fundus color transparencies in a
masked way according to the International Classification and Grading System.
Population-based cohort of all inhabitants aged 55 years or older in a
middle-class suburb of Rotterdam, the Netherlands. Of 5836 persons at risk
of AMD at baseline, 4765 had reliable dietary data and 4170 participated in
the follow-up. Incident AMD, defined as soft distinct drusen with pigment
alterations, indistinct or reticular drusen, geographic atrophy, or
choroidal neovascularization. Incident AMD occurred in 560 participants
after a mean follow-up of 8.0 years (range, 0.3-13.9 years). Dietary intake
of both vitamin E and zinc was inversely associated with incident AMD. The
hazard ratio (HR) per standard deviation increase of intake for vitamin E
was 0.92 (95% confidence interval [CI], 0.84-1.00) and for zinc was 0.91
(95% CI, 0.83-0.98). An above-median intake of all 4 nutrients, beta
carotene, vitamin C, vitamin E, and zinc, was associated with a 35% reduced
risk (HR, 0.65; 95% CI, 0.46-0.92) of AMD. Exclusion of supplement users did
not affect the results |