The association of angiotensin-converting enzyme gene insertion/deletion polymorphisms with acute mountain sickness susceptibility: a meta-analysis.

Altitude exposure in nonacclimatized subjects may lead to acute mountain sickness (AMS). AMS is defined as headache upon recent arrival to altitude and may be accompanied by loss of appetite, nausea or vomiting, dizziness, fatigue, and poor sleep. Susceptibility for AMS varies and has been linked to angiotensin-converting enzyme (ACE) gene polymorphisms. We performed a meta-analysis of studies to assess the association between the ACE deletion (D) and insertion (I) alleles and AMS from published data. A fixed effects model was applied and study quality was assessed in duplicate. Five studies with a total of 333 AMS cases and 373 healthy controls were assessed. Our results revealed no significant differences in risk for AMS between carriers of ACE deletion and insertion polymorphism alleles.