Persistent organic pollutant exposure as a risk factor of gestational diabetes mellitus: A systematic review and meta-analysis

BackgroundFindings related to the association between persistent organic pollutants (POPs) and gestational diabetes mellitus (GDM) are inconclusive.ObjectivesTo estimate the strength of the association between POP exposure and GDM in a systematic review with meta-analysis.Search strategyMEDLINE, Scopus and Web of Science were searched until July 2023.Selection criteriaCohort and case-control studies analysing the association between POPs and GDM.Data collection and analysisWe assessed the risk of bias using the Quality in Prognosis Studies scale (QUIPS). Standardised mean differences were pooled using random-effect models.Main resultsSixteen articles including 12 216 participants were selected. The risk of bias was high in four articles (25%), moderate in 11 (68.75%) and low in one (6.25%). Small mean difference between GDM cases and controls was observed for PFHpA (0.26, 95% confidence interval [CI] 0.1-0.35, I2 = 0.0%), PCB180 (0.37, 95% CI 0.19-0.56; I2 = 25.3%), BDE47 (0.23, 95% CI 0.0-0.45, I2 = 0%), BDE99 (0.36, 95% CI 0.14-0.59; I2 = 0%), BDE100 (0.42, 95% CI 0.19-0.64; I2 = 0%) and HCB (0.22, 95% CI 0.01-0.42, I2 = 39.6%). No considerable difference was observed for the rest of POPs.ConclusionSmall mean differences between GDM cases and controls were observed for some POPs. However, evidence shows mostly moderate quality and results were heterogeneous. Improved research methodology is needed to assess POPs and GDM risk.