This study aimed to assess the evidence regarding the relationship between early-life antibiotic exposure and childhood overweight/obesity by reviewing observational studies on prenatal antibiotic exposure and systematic reviews on infant antibiotic exposure. A search in Pubmed, Embase and Google Scholar covering the period 1st January till 1st December 2018 led to the identification of five studies on prenatal antibiotic exposure and four systematic reviews on infant antibiotic exposure. Positive trends between prenatal antibiotic exposure and overweight/obesity were reported in all studies; two studies reported a significant overall relationship and the other three reported significant relationships under certain conditions. Effect sizes ranged from odds ratio (OR): 1.04 (0.62-1.74) to relative risk (RR): 1.77 (1.25-2.51). Regarding infant antibiotics, one review concluded there was substantial evidence that infant antibiotic exposure increased the risk of childhood overweight/obesity [pooled effect sizes: RR: 1.21 (1.09-1.33) for overweight and RR: 1.18 (1.12-1.25) for obesity]. Two reviews concluded there was some evidence for a relationship [pooled effect sizes: OR: 1.05 (1.00-1.11) and OR: 1.11 (1.02-1.20)]. The fourth review concluded the studies were too heterogeneous for meta-analyses and the evidence regarding the relationship between infant antibiotic exposure and childhood overweight/obesity was inconclusive. More well-designed studies are needed that include data on intra-partum antibiotics and address important potential confounders (including maternal and childhood infections). This review points to some evidence of a relationship between early-life antibiotic exposure and childhood overweight/obesity; this is especially evident in certain children (i.e. exposed to multiple and broad-spectrum antibiotics, earlier postnatal exposure and male gender) and merits further research.
Keywords: Early life; antibiotics; chronic diseases; microbiome; overweight and obesity.