Ophthalmology：维生素C和E无法防止黄斑变性

近日，一项新的临床试验发现，服用维生素C和E能不能防止老年患者的黄斑变性，黄斑变性是中老年人视力丧失的首要原因。该研究报告在线发表在近期的Ophthalmology杂志上。

研究人员一直希望，维生素以及抗氧化剂可以防止黄斑变性组织侵袭性变化的发生。该疾病涉及视网膜中心的损害，这使得很难看到完整的细节。

研究发现，饮食中有更多抗氧化剂的人黄斑变性的风险较低。但并不能排除饮食或生活习惯是这种关联的原因。

到目前为止，还没有应用维生素E的临床试验。

波士顿布里格姆妇女医院和哈佛医学院首席研究员William G. Christen表示，这项最新的研究是检测维生素E对男性视力影响的时间最长的研究，并首次尝试研究单独维生素C的作用。

在补充维生素8年的中老年男性中，以上两种维生素均没有发现有益处。

该报告为一项正在进行的对14000名50岁及以上美国男性医生研究的一部分。

这些男性被随机分配隔日接受400国际单位（IU）维生素E或安慰剂丸，同时每日服用500 mg维生素C或安慰剂。

8年后，193名男子患黄斑变性并严重到影响他们的视觉。维生素和安慰剂使用者之间的风险几乎是相同的。

但新发病例的速度可能在下降。

doi:10.1016/j.ophtha.2012.01.053
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Vitamins E and C and Medical Record-Confirmed Age-Related Macular Degeneration in a Randomized Trial of Male Physicians

William G. Christen, ScD, Robert J. Glynn, ScD1, Howard D. Sesso, ScD, Tobias Kurth, MD, Jean MacFadyen, BA1, Vadim Bubes, PhD, Julie E. Buring, ScD, JoAnn E. Manson, MD, J. Michael Gaziano, MD

Purpose

To test whether supplementation with alternate-day vitamin E or daily vitamin C affects the incidence of the diagnosis of age-related macular degeneration (AMD) in a large-scale randomized trial of male physicians.

Design

Randomized, double-masked, placebo-controlled trial.

Participants

We included 14 236 apparently healthy United States male physicians aged ≥50 years who did not report a diagnosis of AMD at baseline.

Methods

Participants were randomly assigned to receive 400 international units (IU) of vitamin E or placebo on alternate days, and 500 mg of vitamin C or placebo daily. Participants reported new diagnoses of AMD on annual questionnaires and medical record data were collected to confirm the reports.

Main Outcome Measures

Incident diagnosis of AMD responsible for a reduction in best-corrected visual acuity to ≤20/30.

Results

After 8 years of treatment and follow-up, a total of 193 incident cases of visually significant AMD were documented. There were 96 cases in the vitamin E group and 97 in the placebo group (hazard ratio [HR], 1.03; 95% confidence interval [CI], 0.78–1.37). For vitamin C, there were 97 cases in the active group and 96 in the placebo group (HR, 0.99; 95% CI, 0.75–1.31).

Conclusions

In a large-scale, randomized trial of United States male physicians, alternate-day use of 400 IU of vitamin E and/or daily use of 500 mg of vitamin C for 8 years had no appreciable beneficial or harmful effect on risk of incident diagnosis of AMD.