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Research Paper|Volume 13, Issue 6|pp 8865—8879

Association between prenatal air pollution exposure and risk of hypospadias in offspring: a systematic review and meta-analysis of observational studies

Ze Xing1, Shuang Zhang2,3, Yu-Ting Jiang2,3, Xiu-Xia Wang1, Hong Cui4
  • 1Center of Reproductive Medicine, Shengjing Hospital of China Medical University, Shenyang, China
  • 2Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, Shenyang, China
  • 3Clinical Research Center, Shengjing Hospital of China Medical University, Shenyang, China
  • 4Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
Received: July 27, 2020Accepted: January 4, 2021Published: March 19, 2021
https://doi.org/10.18632/aging.202698

Copyright: © 2021 Xing et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Background: The findings of associations between prenatal air pollution exposure and hypospadias risk in offspring are inconsistent. No systematic review or meta-analysis has yet summarized the present knowledge on the aforementioned topic.

Methods: Relevant manuscripts were identified by searching PubMed and Web of Science databases through January 31, 2020. Summary odds ratios (ORs) with 95% confidence intervals (CIs) in meta-analyses were estimated based on a random effects model. Publication bias was evaluated by funnel plots, Begg’s test, and Egger’s test.

Results: The search identified 3,032 relevant studies. Sixteen studies cumulatively involving 21,701 hypospadias cases and 1,465,364 participants were included. All of these studies were classified as having a low risk of bias. We classified pollutants as nitrogen oxides, particulate matter (PM), ozone, and other exposures. The exposure window to pollutants varied from three months before conception to seven days after delivery. In the meta-analyses, only PM2.5 exposure in the first trimester was related to increased risk of hypospadias (per 10 μg/m3 OR = 1.34; 95% CI: 1.06–1.68).

Conclusion: We found evidence for an effect of PM2.5 exposure on hypospadias risk. Improvements in the areas of study design, exposure assessment, and specific exposure window are needed to advance this field.