COMMENTARY

The Value of Vitamins in Glaucoma

Shivani S. Kamat, MD; Shuchi B. Patel, MD

Disclosures

June 06, 2013

In This Article

Study Findings

Of the 2912 participants, 203 reported a history of glaucoma, representing 5.42% of the US population.

Of interest, several demographic characteristics differed significantly between those who did and did not report having glaucoma:

Mean age (67.4 vs 56.5 years, P = .0001);

Race (P = .0023);

Annual household income (P = .0466);

Smoking status (P = .0006); and

Daily number of alcoholic drinks consumed over the past year (P = .0228).

Multivariate regression models were constructed to compare the odds of self-reported glaucoma with supplemental vitamin intake. Model A was adjusted only for age, model B for age and other demographic characteristics, and model C for age, demographic characteristics, health-related behaviors, self-reported general health, and comorbid conditions.

Vitamin consumption and glaucoma. Supplemental consumers of vitamin A did not have increased odds of glaucoma, regardless of adjustment for confounders or amount of consumption. Participants who consumed vitamin C (≤ 100 mg/day) had significantly lower odds of glaucoma compared with those who consumed no vitamin C (model C odds ratio [OR], 0.34; 95% confidence interval [CI], 0.13-0.87). This correlation was also significant at the highest quartile dosage of vitamin C (>900 mg/day; model C adjusted OR, 0.47; 95% CI, 0.23-0.97).

Supplemental consumers of vitamin E at the highest quartile level (>400 IU/day) had higher odds of glaucoma compared with nonconsumers in the unadjusted model (OR, 3.40; 95% CI, 1.58-7.33), with persistent statistical significance despite adjustment for age and demographics (OR, 3.15; 95% CI, 1.29-7.72). However, after further adjustment for health-related behaviors and general health condition, this correlation was no longer statistically significant. Higher doses of vitamin E were associated with a higher prevalence of glaucoma (P = .004), and further adjusted models showed borderline significant P values for this association; however, significant dose-response relationships were not observed in any model for the other vitamins.

Serum vitamin levels and glaucoma. Similar multivariate regression models were used to compare odds of self-reported glaucoma among participants on the basis of their serum values of vitamins A, C, and E. Participants with higher serum levels of vitamin A did not have lower odds of having glaucoma; however, there was a greater chance of having glaucoma with increasing quintiles of serum vitamin A in the unadjusted model (P = .002), which persisted after adjusting for age and demographics (P = .032). In model C, this association was borderline significant (P = .052). There was no association between serum vitamin C levels and the odds of glaucoma. Those with the highest quintile of serum alpha-tocopherol (>1720 µg/dL) had higher odds of having glaucoma compared with lower serum levels (OR, 1.59; 95% CI, 1.02-2.47) in the unadjusted model, and there was a trend of increasing odds of glaucoma with increasing quintiles of alpha-tocopherol levels (P = .009). However, these findings did not persist when adjusting for age. Furthermore, participants with serum gamma-tocopherol levels in the second to fourth quintiles (>114 µg/dL to >228 µg/dL) had reduced odds of glaucoma compared with those with the lowest quintile (≤ 114 µg/dL), but only in the unadjusted model.

In conclusion, no compelling evidence suggests a relationship between dietary supplementation with vitamins A or E and glaucomatous disease. Weak evidence suggests that vitamin C intake is associated with lower odds of glaucoma, although these findings should be investigated further before therapeutic recommendations can be established.

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