Hormone replacement therapy and Parkinson’s disease risk in women: a meta-analysis of 14 observational studies

Abstract

Peifu Wang, Jilai Li, Shi Qiu, Honfeng Wen, Jichen DuDepartment of Neurology, Aerospace Center Hospital, Peking University Aerospace Clinical College, Beijing, People’s Republic of ChinaBackground and purpose: Published data on the relationship of hormone replacement therapy (HRT) with Parkinson’s disease (PD) were inconclusive. Thus, a systematic meta-analysis of observational studies was performed to clarify this topic.Methods: The databases of PubMed and EMBASE were searched for case–control or cohort studies published up till June 2, 2014. Meta-analysis of the relative risks (RRs) with 95% confidence intervals (CIs) was estimated using random-effects models.Results: A final total of ten case–control and four cohort studies were included in our meta-analysis. The overall combined RR of PD for ever users versus never users of HRT was 1.00 (95% CI: 0.84–1.20). Limited to those subjects who only use estrogen, a similar trend was detected (RR: 0.95, 95% CI: 0.69–1.30). In the subgroup analysis by study design, no significant association was observed in case–control studies (RR: 0.79, 95% CI: 0.62–1.02), whereas a positive association was found in cohort studies (RR: 1.24, 95% CI: 1.10–1.40). In further analysis according to study quality, an inverse association was found in the low-quality group (RR: 0.58, 95% CI: 0.40–0.82), whereas a positive association was found in the high-quality group (RR: 1.16, 95% CI: 1.02–1.31).Conclusion: In summary, our results of meta-analysis do not support a protective role of HRT in female PD development.Keywords: Parkinson’s disease, hormone replacement therapy, hormone meta-analysis