Epidemiologic studies have reported inconsistent associations between menarcheal age and ovarian cancer risk. To our knowledge, a meta-analysis for the association between menarcheal age and ovarian cancer has not been reported. Relevant published studies of menarcheal age and ovarian cancer were identified using MEDLINE, EMBASE, and Web of Science through the end of April, 2012. Two authors (T-TG and Q-JW) independently assessed eligibility and extracted data. We pooled the relative risks (RR) from individual studies using a random-effects model and performed heterogeneity and publication bias analyses. A total of 27 observational studies consisting of 22 case-control and 5 cohort studies were included in our analysis. In a pooled analysis of all studies, a statistically significant inverse association was observed between menarcheal age (for the oldest compared with the youngest category) and ovarian cancer risk (RR=0.85; 95% confidence interval (95% CI) 0.75–0.97). The pooled RRs of ovarian cancer for the oldest versus the youngest categories of menarcheal age in prospective and case-control studies were 0.89 (95% CI 0.76–1.03) and 0.84 (95% CI 0.70–0.99), respectively. Inverse associations between menarcheal age and ovarian cancer risk were observed in most sub-groups, but the association was restricted to invasive and borderline serous ovarian cancer. In conclusion, findings from this meta-analysis support that menarcheal age was inversely associated with the risk of ovarian cancer. More large studies are warranted to stratify results by different cancer grading and histotype of ovarian cancer.

We performed this meta-analysis of epidemiologic studies to investigate the associations between circulating adiponectin, leptin and adiponectin-leptin (A/L) ratio and endometrial cancer risk. Relevant manuscripts were identified by searching PubMed and ISI Web of Science databases as well as by manual searching the references cited in retrieved manuscripts. Random-effects models were used to estimate summary odds ratio (SOR) and 95% confidence intervals (CIs) for aforementioned associations. Fourteen manuscripts with 13 studies (five nested case-control and eight case-control studies) cumulatively involving a total of 1,963 endometrial cancer cases and 3,503 noncases were included in the analyses. Overall, comparing persons with circulating concentrations of adiponectin, leptin and A/L ratio in the top tertile with persons with concentrations of these biomarkers in the bottom tertile yielded SORs of 0.47 (95% CI: 0.34-0.65; I 2 5 63.7%; n 5 13), 2.19 (95% CI: 1.44-3.31; I 2 5 64.2%; n 5 7),and 0.45 (95% CI: 0.24-0.86; I 2 5 90.1%; n 5 5), respectively. Notably, there was an 18% reduction in risk for per each 5 lg/mL increment in circulating adiponectin concentrations (SOR 5 0.82; 95% CI: 0.74-0.90; I 2 5 49%; n 5 8). Stratifying by study characteristics and whether these studies considered or adjusted for potential confounders, the findings were robust in the analyses of circulating adiponectin and leptin. No evidence of publication bias was detected. In conclusion, the findings from this metaanalysis suggest that increased circulating adiponectin and A/L ratio or decreased leptin concentrations were associated with reduced risk of endometrial cancer. Further prospective designed studies are warranted to confirm our findings.Endometrial cancer is the second most common gynecologic malignancy worldwide, with approximately 0.3 million new cases in 2012. 1 There is no doubt that obesity is a wellrecognized risk factor for this disease. Recently, the biological mechanisms linking obesity and endometrial cancer have largely centered on the aromatization of androgens in adipose tissue, leading to increased circulating estradiol levels 2 which have been the primary stimulants of endometrial proliferation. 3 However, this mechanism cannot fully explain the incidence of endometrial cancer in obese women. Experimental studies have provided evidence that adipokines, which are associated with hyperinsulinemia and degree of insulin resistance independent of adiposity, are also involved in the development of endometrial cancer.Adipose tissue was previously considered to be an energystorage site. During recent decades, this tissue has been found to be an endocrine organ producing and secreting several bioactive peptides, including adipokines such as adiponectin and leptin. 4 Biological studies have shown that adiponectin, the most abundant adipokine, is not only inversely associated with obesity as well as hyperinsulinemia 5,6 but appears to have anti-inflammatory, antiangiogenic and antidiabetic properties 7,8 ; In contrast,...

Evidence between age at menarche and endometrial cancer risk have been controversial. Therefore, we conducted a meta-analysis of prospective studies to analyze the aforementioned association. Relevant studies were identified by searching PubMed and EMBASE databases until the end of June 2015. A random-effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs) for associations between menarcheal age and endometrial cancer risk. Our meta-analysis included eight prospective studies involving 4553 subjects with endometrial cancer. The summarized RRs of endometrial cancer for menarcheal age were 0.68 (95%CI = 0.58–0.81, I2 = 41.9%, P = 0.099, n = 8) when comparing women with oldest category of menarcheal age with women with youngest category of menarcheal age. Notably, there was an 4% reduction in risk for per 2 years delay in menarcheal age (summarized RR = 0.96; 95%CI = 0.94–0.98, I2 = 45.7%, P = 0.101, n = 6). Additionally, significant inverse associations were consistent within all stratified analyses. There was no evidence of publication bias or significant heterogeneity between subgroups detected by meta-regression analyses. Our findings support the hypothesis that late menarcheal age is inversely associated with endometrial cancer risk. Further larger prospective or pooled studies are warranted to fully adjust for potential confounders and distinguish whether the associations differ by histological subtypes of endometrial cancer.

Based on the findings of this meta-analysis, ever use of OC is associated with lower risk of CRC. Additionally, there is a statistically significant nonlinear inverse association between the duration of OC use and CRC risk.