Coffee and caffeine intake and risk of endometriosis: a meta-analysis

Purpose: The potential association between endometriosis and coffee/caffeine consumption has been analysed in several epidemiological studies. In order to establish whether caffeine influences the risk of endometriosis, we provide to summarize the evidence from published studies on this issue. Methods: We performed a meta-analysis of epidemiological studies published up to January 2013. We computed summary relative risks (RR) of endometriosis for any, high and low versus no coffee/caffeine consumption. Results: We identified a total eight studies, six case-control and two cohort studies, including a total of 1,407 women with endometriosis. The summary RR for any versus non-consumption were 1.26 [95 % confidence interval (CI) 0.95-1.66] for caffeine and 1.13 (95 % CI 0.46-2.76) for coffee consumption; the overall estimate was 1.18 (95 % CI 0.92-1.49). The summary RR were 1.09 (95 % CI 0.84-1.42) and 1.09 (95 % CI 0.89-1.33) for high and low caffeine consumption as compared to no consumption, respectively. Conclusion: The present meta-analysis provided no evidence for an association between coffee/caffeine consumption and the risk of endometriosis. Coffee/caffeine consumption, as currently used in diet, does not carry a health risk.