Glucose-6-phosphate dehydrogenase (G6PD) deficiency in nonarteritic anterior ischemic optic neuropathy in a Sardinian population, Italy.

PURPOSE: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human genetic abnormalities, with a high prevalence in Sardinia, Italy. Evidence indicates that G6PD-deficient patients are protected against ischemic heart and cerebrovascular disease and retinal vein occlusion. The purpose of this study was to assess the frequency of G6PD deficiency in Sardinian patients with nonarteritic anterior ischemic optic neuropathy (NAION) and ascertain whether G6PD deficiency may offer protection against NAION.

METHODS

Erythrocyte G6PD activity was determined by using a quantitative assay in 140 patients with NAION and 280 age- and gender-matched comparison patients. Conditional logistic regression models were used to investigate the association between G6PD deficiency and NAION.

RESULTS

G6PD deficiency was found in 7 (5%) patients with NAION and 34 (12.1%) control subjects. Differences between cases and controls were statistically significant (P = 0.02). Conditional logistic regression analysis, including as covariates G6PD deficiency, hypertension, diabetes, and hypercholesterolemia, revealed that G6PD deficiency was significantly associated with decreased risk for NAION (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.17-0.94, P = 0.035). Conditional logistic regression analyses, including systolic or diastolic blood pressure and plasma glucose and cholesterol levels confirmed that G6PD deficiency was associated with a decreased risk for NAION, but the ORs were not significant at the 0.05 significance level (P = 0.085 and P = 0.071). Models including gender x G6PD deficiency interaction disclosed that gender was not an effect modifier of G6PD deficiency (P > 0.20).

CONCLUSIONS

The frequency of G6PD deficiency in patients with NAION was significantly lower than expected. Results suggest that G6PD-deficient patients in the Sardinian population have a significantly decreased risk of having NAION.