BACKGROUND: Previous studies have demonstrated some associations between dietary vitamin A intake and ovarian cancer risk with an inconsistent relationship. We therefore performed the present study to further explore the association between them. METHODS: Databases of PubMed, Embase, and Web of Science were retrieved up to September 1, 2019. Summarized relative risk (RR) with corresponding 95% confidence intervals (CI) were calculated. Stata 14.0 software was used for data analysis. RESULTS: Fifteen articles involving 4882 cases and 443,179 participants were included in this meta-analysis. A positive association between dietary vitamin A intake and ovarian cancer risk was found (RR = 0.816, 95%CI = 0.723–0.920, I2 = 48.4%, Pfor heterogeneity = 0.019). Significant association was also found in case–control studies (RR = 0.769, 95%CI = 0.655–0.902), but not in cohort studies. When we performed the analysis between ovarian cancer risk and geographic locations, we found an inverse association in North American populations (RR = 0.825, 95%CI = 0.720–0.946), instead of other populations. CONCLUSIONS: In summary, findings from the present study suggested that higher dietary intake of vitamin A may contribute to the lower development of ovarian cancer, especially among North Americans.

Background This study aimed to survey the overall situation of birth defects (BDs) among citizens of Hangzhou, China, and the risk factors of different BD types. Material/Methods We collected the data of 4349 perinatal infants with BDs in Hangzhou. The potentially associated risk factors of BDs were recorded and logistic regression analysis was used to predict the high incidence of BDs. Results Among all perinatal infants with BDs, there were 4105 (94.3%) single births, 225 (5.2%) twin births, and 10 (0.2%) multiple births. In clinical outcomes, there were 2477 (57.0%) live births, 1806 (41.5%) dead fetuses, and 11 (0.3%) stillbirths. Down syndrome ranked first, accounting for 30.7% of the total births, followed by cleft lip and polydactyly. Low family income, nulliparity, high parity, high education level, and taking contraceptives in early pregnancy were found to be risk factors of Down syndrome. Low parity, low education level, and pesticide exposure were found to be risk factors of cleft lip. For polydactyly, young age of the mother and a parity above 0 were identified as risk factors. Conclusions Different risks factors can influence BD development and potentially help to predict specific BD types, such as demographic features and harmful exposure in early pregnancy.

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