Association of Endothelial Nitric Oxide Synthase (eNOS) G894T Polymorphism With High Altitude Pulmonary Edema Susceptibility: A Meta-Analysis

Background.-High altitude pulmonary edema (HAPE) is a potentially deadly disease associated with exposure to altitudes greater than 3000 m. Individuals who have previously experienced HAPE are at a significantly higher risk of recurrence, suggesting an underlying genetic component to HAPE pathogenesis. In a previous nuclear genomic study of individual variation in susceptibility to HAPE, the endothelial nitric oxide synthase (eNOS) gene G894T polymorphism was identified as being associated with HAPE. However, another study found no association. Because of the low incidence of HAPE, sample sizes in current reports have been relatively limited. In this study, the association between the eNOS G894T polymorphism and HAPE was assessed through a meta-analysis of published data. Methods.-The literature was searched in PubMed, Web of Science, and Embase for papers published before July 15, 2011. A fixed-effects model and a random-effects model were applied (Revman 5.0) on the basis of heterogeneity, and study quality was assessed in duplicate. Results.-Five studies with 360 HAPE patients and 469 control subjects were analyzed. There were no significant differences between carriers of the eNOS 894G and 894T polymorphism alleles in terms of the risk of developing HAPE. Conclusions.-The eNOS 894G and 894T polymorphism alleles are not associated with HAPE incidence.