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Carotenoids and omega-3 fatty acids do not reduce risk of advanced AMD

Clinical Question:
Can increased dietary intake of lutein plus zeaxanthin (carotenoids), omega-3 fatty acids, or both, reduce the risk of advanced age-related macular degeneration?

Bottom Line:
Adding the carotenoids lutein and zeaxanthin and/or standard omega-3 fatty acids as daily oral supplements to standard antioxidant vitamins and minerals did not further reduce the risk of advanced age-related macular degeneration (AMD). (LOE = 1b-)

Reference:
The Age-Related Eye Disease Study 2 (AREDS2) Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration. The AREDS2 randomized clinical trial. JAMA 2013;309(19):2005-2015.  [PMID:23644932]

Study Design:
Randomized controlled trial (double-blinded)

Funding:
Industry + govt

Allocation:
Uncertain

Setting:
Outpatient (specialty)

Synopsis:
Previous studies from the Age-Related Eye Disease Study (AREDS) reported that daily oral supplementation with antioxidant vitamins and minerals reduce the risk of advanced AMD. Whether additional dietary intake of carotenoids and omega-3 fatty acids also reduce the risk of AMD is uncertain. As part of the AREDS these investigators identified adults, aged 50 to 85 years, at high risk for progression to advanced AMD with either bilateral large drusen or large drusen in 1 eye and advanced AMD in the other eye. Patients (n = 4203) taking at least 75% of supplements during a placebo run-in adherence phase randomly received assignment (uncertain allocation concealment) to 1 of 4 treatment groups: (1) standard AREDS supplements plus placebo; (2) standard supplements plus the carotenoids lutein and zeaxanthin; (3) standard supplements plus omega-3 fatty acids; or (4) standard supplements plus the carotenoids and omega-3 fatty acids. The standard AREDS supplements included vitamin C (500 mg), vitamin E (400 IU), beta-carotene (15 mg), zinc (80 mg), and copper (2 mg). A second subgroup of consenting patients (n = 3420) randomly received a modified AREDS formulation with either a lower dose of zinc (25 mg), no beta-carotene (which has been shown to increase the risk of lung cancer in smokers), or both the lower dose of zinc and no beta-carotene. Individuals assessing outcomes remained masked to treatment group assignment. Complete follow-up occurred for 97% of participants for a median of 4.9 years. A random pill count analysis determined that more than 80% of participants in each treatment group took at least 75% of the study medications. Using intention-to-treat analysis, there were no significant differences between the 4 treatment groups in the probability of progression to advanced AMD by 5 years or in the development of at least moderate vision loss. There was also no apparent effect on disease progression or vision loss by eliminating the beta-carotene or reducing the zinc dose. No clinically significant differences in reported serious adverse events occurred. The study was adequately powered to have a 90% chance of detecting a 25% difference between the treatment groups in the progression to advanced AMD. As expected, significantly more lung cancers occurred among smokers in the beta-carotene group than in the no beta-carotene group.

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