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Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration

  • Review
  • Intervention

Authors

  • Jennifer R Evans

    Corresponding author
    1. London School of Hygiene & Tropical Medicine, Cochrane Eyes and Vision Group, ICEH, London, UK
    • Jennifer R Evans, Cochrane Eyes and Vision Group, ICEH, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. jennifer.evans@lshtm.ac.uk.

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Abstract

Background

It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption.

Objectives

The objective of this review was to assess the effects of antioxidant vitamin or mineral supplementation on the progression of age-related macular degeneration (AMD).

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2007, Issue 3); MEDLINE (1966 to August 2007); EMBASE (1980 to August 2007); NRR (2007, Issue 3); AMED (1985 to January 2006); PubMed (24 January 2006 covering last 60 days) and SIGLE (1980 to March 2005), reference lists of identified reports and the Science Citation Index. We contacted investigators and experts in the field for details of unpublished studies.

Selection criteria

We included randomised trials comparing antioxidant vitamin or mineral supplementation (alone or in combination) to a control intervention in people with AMD.

Data collection and analysis

The author extracted data and assessed trial quality. Where appropriate, data were pooled using a random-effects model unless three or fewer trials were available in which case a fixed-effects model was used.

Main results

Nine trials were included in this review. The majority of people were randomised in one trial (AREDS in the USA) that found a beneficial effect of antioxidant (beta-carotene, vitamin C and vitamin E) and zinc supplementation on progression to advanced AMD (adjusted odds ratio 0.68, 99% confidence interval 0.49 to 0.93). People taking supplements were less likely to lose 15 or more letters of visual acuity (adjusted odds ratio 0.77, 99% confidence interval 0.58 to 1.03). Hospitalisation for genito-urinary problems was more common in people taking zinc and yellowing of skin was more common in people taking antioxidants. The other trials were, in general, small and the results were inconsistent.

Authors' conclusions

The evidence as to the effectiveness of antioxidant vitamin and mineral supplementation in halting the progression of AMD comes mainly from one large trial in the USA. The generalisability of these findings to other populations with different nutritional status is not known. Further large, well-conducted randomised controlled trials in other populations are required. Long-term harm from supplementation cannot be ruled out. Beta-carotene has been found to increase the risk of lung cancer in smokers; vitamin E has been associated with an increased risk of heart failure in people with vascular disease or diabetes.

摘要

背景

抗氧化維生素和礦物質補充劑減緩老年性黃斑退化的速度

有學者認為,抗氧化劑可以中和光吸收過程中產生之自由基,防止視網膜之細胞損傷。

目標

這篇文獻回顧的目的是評估抗氧化維生素和礦物質補充劑對於老年性黃斑退化(AMD)病程發展之延緩效果。

搜尋策略

我們搜尋的資料庫包括:Cochrane Library(2007年第3期,Cochrane Central Register of Controlled Trials);MEDLINE(1966年至2007年8月);EMBASE(1980年至2007年8月);NRR(2007年第3期);AMED(1985年至2006年1月);PubMed(2006年1月24日,上述日期之前的60日以內);SIGLE(1980年至2005年3月);以及其他經確認的報告和科學引文索引之參考文獻。我們聯繫試驗主持人員和該領域的專家以瞭解未發表的研究報告之詳細情況。

選擇標準

納入的標準為:在老年性黃斑退化病人中,比較抗氧化維生素和礦物質補充劑(單一或合併使用)與對照組做比較之隨機試驗。

資料收集與分析

作者摘錄資料並評估試驗的品質。所有試驗資料以「隨機效果模式」進行集中處理,若只有三個或更少的試驗進入分析,則使用「固定效果模式」。

主要結論

九個臨床試驗被納入本次文獻回顧。在最大的一個隨機分配試驗中(AREDS in the USA)發現,大多數人接受抗氧化劑(β胡蘿蔔素,維生素C和維生素E)和鋅的補充對於延緩嚴重老年性黃斑退化是有益處的(調整後勝算比0.68,99%信賴區間0.49至0.93);使用補充劑的人們較不易失去字母辨識的視力(調整後勝算比0.77,99%信賴區間0.58到1.03)。因泌尿生殖問題住院的情況較常見於使用鋅的人,皮膚變黃的情況較常見於使用抗氧化劑者。至於其他八個試驗,一般來說,規模小且結果不一致。

作者結論

抗氧化維生素和礦物質補充劑在減緩老年性黃斑退化的證據主要來自一個在美國的大規模試驗。這些調查結果對其他不同營養狀況的人們是否適用並不清楚,這需要更多在其他族群的大型且嚴謹之隨機對照試驗來證實。長期補充這些物質的損害也不能排除,例如 β胡蘿蔔素會增加吸煙者患肺癌的風險;維生素E被發現會增加血管疾病或糖尿病患者心臟衰竭的風險。

翻譯人

本摘要由高雄榮民總醫院金沁琳翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

老年性黃斑病變影響的位置是眼底視網膜的中央區,而抗氧化維生素和礦物質補充劑,則被用來減緩老年性黃斑病變的進展。視網膜退化的原因可以是隨著年老,或其他病變而惡化,這會導致喪失中央視力。有人認為,這種疾病的進展速度可能會因為人們在日常生活中多吃一些富含抗氧化維生素(類胡蘿蔔素,維生素C和E)或礦物質(硒和鋅)的飲食而減緩。作者確認了9個隨機對照試驗四項試驗在美國,另外五個則分別在澳大利亞,奧地利,瑞士,英國和中國。試驗的文獻回顧結果顯示,補充抗氧化劑和鋅可能對於老年性黃斑病變有些許好處。但這些補充品的長期損害也不能排除。需要對特定族群或其他營養狀況不同的人進行大型且嚴謹之試驗。

Plain language summary

Antioxidant vitamins and mineral supplements to slow down the progression of age-related macular degeneration

Age-related macular degeneration (AMD) is a condition affecting the central area of the retina (back of the eye). The retina can deteriorate with age and some people get lesions that can lead to loss of central vision. It has been suggested that progression of the disease may be slowed down in people who eat a diet rich in antioxidant vitamins (carotenoids, vitamins C and E) or minerals (selenium and zinc). The author identified nine randomised controlled trials; four trials based in the USA, four in Australia, Austria, Switzerland and the UK and one in China. The review of trials found that supplementation with antioxidants and zinc may be of modest benefit in people with AMD. Long-term harm from these supplements cannot be ruled out. Large well-conducted trials in a range of populations and with different nutritional status are required.

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