A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E and beta carotene for age-related cataract and vision loss - AREDS Report No. 9
A. Kassoff et al., A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E and beta carotene for age-related cataract and vision loss - AREDS Report No. 9, ARCH OPHTH, 119(10), 2001, pp. 1439-1452
Background: Experimental and observational data suggest that micronutrients
with antioxidant capabilities may retard the development of age-related ca
taract.
Objective: To evaluate the effect of a high-dose antioxidant formulation on
the development and progression of age-related lens opacities and visual a
cuity loss.
Design: The 11-center Age-Related Eye Disease Study (AREDS) was a double-ma
sked clinical trial. Participants were randomly assigned to receive daily o
ral tablets containing either antioxidants (vitamin C, 500 mg; vitamin E, 4
00 IU; and beta carotene, 15 mg) or no antioxidants. Participants with more
than a few small drusen were also randomly assigned to receive tablets wit
h or without zinc (80 mg of zinc as zinc oxide) and copper (2 mg of copper
as cupric oxide) as part of the age-related macular degeneration trial. Bas
eline and annual (starting at year 2) lens photographs were graded at a rea
ding center for the severity of lens opacities using the AREDS cataract gra
ding scale.
Main Outcome Measures: Primary outcomes were (1) an increase from baseline
in nuclear, cortical, or posterior subcapsular opacity grades or cataract s
urgery, and (2) at least moderate visual acuity loss from baseline (greater
than or equal to 15 letters). Primary analyses used repeated-measures logi
stic regression with a statistical significance level of P = .01. Serum lev
el measurements, medical histories, and mortality rates were used for safet
y monitoring.
Results: Of 4757 participants enrolled, 4629 who were aged from 55 to 80 ye
ars had at least 1 natural lens present and were followed up for an average
of 6.3 years. No statistically significant effect of the antioxidant formu
lation was seen on the development or progression of age-related lens opaci
ties (odds ratio = 0.97, P = .55). There was also no statistically signific
ant effect of treatment in reducing the risk of progression for any of the
3 lens opacity types or for cataract surgery. For the 1117 participants wit
h no age-related macular degeneration at baseline, no statistically signifi
cant difference was noted between treatment groups for at least moderate vi
sual acuity loss. No statistically significant serious adverse effect was a
ssociated with treatment.
Conclusion: Use of a high-dose formulation of vitamin C, vitamin E, and bet
a carotene in a relatively well-nourished older adult cohort had no apparen
t effect on the 7-year risk of development or progression of age-related le
ns opacities or visual acuity loss.