The relationship between smoking and dysmenorrhea: A meta-analysis.

Many studies have investigated the potential association between smoking and dysmenorrhea. However, results from such studies have been inconsistent. In this study, we assessed the association between smoking and dysmenorrhea by meta-analysis. We performed a systematic search of the international databases, including PubMed, Scopus, Web of Science, EBSCO and Google Scholar by the MeSH heading and/or additional terms to obtain relevant studies published from 1990 until 2017. I2 statistics were used to assess heterogeneity. Pooled effects size was obtained using a random effects model. Subgroup analyses were also conducted. Data were analyzed through Stata software version 12 (Stata Corp, College Station, TX, USA). A total of fourteen studies were included in meta-analysis. A significant positive association was observed between current smoking and dysmenorrhea in both the unadjusted (odds ratio [OR] = 1.60; 95 percent confidence interval [CI]: 1.35, 1.85) and adjusted models (AOR = 1.44; 95 percent CI: 1.18, 1.69). Also, the association between current smoking and primary dysmenorrhea was significant only in the unadjusted model (OR = 1.53; 95 percent CI: 1.21, 1.85). The pooled effects size showed a significant association between smoking and dysmenorrhea in the fourteen eligible studies. This provides a new approach for prevention from dysmenorrhea in females for policymakers.