Risk of Parkinson's Disease in the Users of Antihypertensive Agents: An Evidence from the Meta-Analysis of Observational Studies.

Background. Antihypertensive agents have been shown to inhibit oxidative stress and inflammatory response and thus neuroprotection in Parkinson's disease (PD). Epidemiological evidence suggests inconsistency between use of antihypertensives and risk of PD. This study is aimed to examine the association between antihypertensive use and risk of PD. Methods. Literature search in PubMed, EMBASE, and PsycINFO database was undertaken through February 2012 looking for observational studies evaluating the association between antihypertensive drug use and risk of PD. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using random-effects model (DerSimonian and Laird method). Subgroup analyses and sensitivity analysis were also performed. Results. Seven relevant studies including a total of 28,32,991 subjects were included. Pooled RR of overall use of antihypertensive agents was found to be 0.95 (95% CI 0.84-1.05). A significant reduction in the risk of PD was observed among users of calcium channel blockers (RR 0.82, 95% CI 0.71-0.93). Significant heterogeneity (I (2) = 76.2%) but no publication bias was observed. Conclusions. Overall use of antihypertensive agents showed no significant association with the risk of PD. CCBs provided significant protective role. However, studies with large sample size and dose relationships are required to strengthen our hypothesis.