The quality of evidence is downgraded by inconsistency (variability in results).
A Cochrane review [Abstract] 1 included 26 studies with a total of 11 952 subjects. Thirteen studies compared multivitamins with controls in people with early and moderate AMD. Most evidence came from the Age-Related Eye Disease Study (AREDS) in the USA. People with intermediate AMD taking antioxidant vitamins were less likely to progress to late AMD (both neovascular AMD and geographic atrophy) and had a lower risk of losing 3 or more lines of visual acuity (table T1). One study of 110 people suggested higher quality of life scores (National Eye Institute Visual Function Questionnaire) in treated compared with the non-treated people after 24 months (mean difference (MD 12.30, 95% CI 4.24 to 20.36).
| Outcome | Relative effect(95 % CI) | Risk with placebo | Risk with antioxidant multivitamin and mineral supplement | Participants (studies) |
|---|---|---|---|---|
| Progression to late AMD (neovascular AMD, geographic atrophy, or both) | OR 0.72(0.58 to 0.90) | 430 per 1000 | 352 per 1000(304 to 404) | 2445 (3) |
| Progression to neovascular AMD | OR 0.62(0.47 to 0.82) | 300 per 1000 | 210 per 1000(168 to 260) | 1206 (1) |
| Progression to geographic atrophy | OR 0.75(0.51 to 1.10) | 300 per 1000 | 243 per 1000(179 to 320) | 1206 (1) |
| Progression to visual loss (loss of 3 or more lines on logMAR chart) | OR 0.77(0.62 to 0.96) | 430 per 1000 | 367 per 1000(319 to 420) | 1791 (1) |
Six studies compared lutein (with or without zeaxanthin) with placebo and 1 study compared a multivitamin including lutein/zeaxanthin with multivitamin alone. The duration of supplementation and follow-up ranged from 6 months to 5 years. Most evidence came from the AREDS2 study in the USA. People taking lutein or zeaxanthin may have similar or slightly reduced risk of progression to late AMD (RR 0.94, 95% CI 0.87 to 1.01; 6891 eyes), neovascular AMD (RR 0.92, 95% CI 0.84 to 1.02; 6891 eyes), and geographic atrophy (RR 0.92, 95% CI 0.80 to 1.05; 6891 eyes). A similar risk of progression to visual loss of 15 or more letters was seen in the lutein and control groups (RR 0.98, 95% CI 0.91 to 1.05; 6656 eyes). Quality of life (measured with Visual Function Questionnaire) was similar between groups in 1 study of 108 participants (MD 1.48, 95% -5.53 to 8.49).
One study (1204 people enrolled from the general population, 19 % had AMD) compared vitamin E with placebo. The number of late AMD events was low (N = 7). The estimate of effect was uncertain (RR 1.36, 95% CI 0.31 to 6.05) and there was no evidence of any effect of treatment on visual loss (RR 1.04, 95% CI 0.74 to 1.47).
Five studies compared zinc with placebo. The duration of supplementation and follow-up ranged from 6 months to 7 years. People taking zinc supplements were less likely to progress to late AMD (OR 0.83, 95% CI 0.70 to 0.98; 3790 participants), neovascular AMD (OR 0.76, 95% CI 0.62 to 0.93; 2442 participants), or visual loss (OR 0.87, 95% CI 0.75 to 1.00).
Primary/Secondary Keywords