LATEBREAKER
Reproductive
The Impact of Unmeasured Confounding on the Association between Maternal Periodontitis and Adverse Birth Outcomes: Meta-Analyses of Observational Studies Abdullah Al-Taiar* Abdullah Al-Taiar May Salama Denise McKinney Sultan Alsullum Eric Mishio Bawa Anwar T. Merchant
Background and objectives: Maternal periodontitis has been consistently linked to adverse birth outcomes. However, a causal relationship is not established due to potential unmeasured confounding factors in observational studies and inconclusive results from randomized controlled trials. This study aimed to assess the impact of unmeasured confounding factors in meta-analyses examining the association between maternal periodontal disease and preterm birth or low birth weight.
Methods: We searched PubMed/Medline, the Cochrane database for systematic reviews, Embase, Google Scholar for articles published between 2002 and 2023. Systematic reviews with meta-analyses of observational studies were included if either preterm birth or low birth weight were the outcome and were published in English between 2002 and 2023. Search results were entered into Rayyan software after removing duplicates. Two researchers independently screened titles and abstracts, with a third reviewer resolving discrepancies. This study followed the Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines and was registered in PROSPERO under number CRD42023400331.
Results: There were 62 original studies from 9 meta-analyses meeting the inclusion criteria. In a random-effects meta-analysis of 19 cohort studies, more than 80% of the studies would have RR>2.00 even if an unmeasured confounder were three times more prevalent in the exposed group and raised the risk of preterm birth 3-fold. Similarly, in a meta-analysis of 10 cohort studies, if the association between an unmeasured confounder and maternal periodontitis as well as low birth weight were RR >3, 80% of the studies in that meta-analysis would have RR>2.00. Publication bias in these meta-analyses may have inflated the summary measures between maternal periodontal disease and preterm birth or low birth weight.
Conclusions: Associations between maternal periodontal disease and adverse birth outcomes in observational studies appear robust to unmeasured confounding factors, but publication bias may tend to inflate them. These findings support the hypothesis that maternal periodontal disease is causally related to adverse birth outcomes.