Angiotensin converting enzyme insertion/deletion polymorphism and risk of pregnancy hypertensive disorders: a meta-analysis.

BACKGROUND: The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been reported inconsistently as being associated with risk of pregnancy hypertensive disorders (PHDs). We examined these associations by performing a meta-analysis.

METHODS: Two investigators independently consulted the Medline, Embase, CNKI, and Chinese Biomedicine databases. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated in fixed- and random-effects models when appropriate. Subgroup analyses were performed by ethnicity, types of PHD (gestational hypertension, pre-eclampsia and eclampsia), country and Hardy-Weinberg equilibrium (HWE) in controls.

RESULTS: This meta-analysis included 30 case-control studies with 3523 cases and 4817 controls. Overall, we found that the DD variant of the ACE I/D polymorphism was associated with a significantly increased PHD risk. In the subgroup analysis by ethnicity, the results suggested that the DD genotype was significantly associated with risk of PHD development among Asians and Caucasians. Moreover, when stratifying by types of PHD, a significantly increased risk was observed for pre-eclampsia. Interestingly, when stratifying by country, a significantly elevated risk was found among 'others' countries (those that were not China or Korea). Limiting the analysis to the studies within HWE, the results were persistent and robust.

CONCLUSION: This meta-analysis suggests that the I/D polymorphism of ACE may be associated with PHD risk, especially among Asians and Caucasians.