Environmental antibiotics exposure and childhood obesity: A cross-sectional case-control study.

Children's exposures to environmental antibiotics are a major public health concern. However, limited data are available on the effects of environmental antibiotic exposures on childhood obesity. Our study aimed to explore this relationship. We conducted a cross-sectional case-control study nested in a population-based survey of primary school students, including 1855 obese and 1875 random selected control children. A total of 10 antibiotics in urine samples were measured by liquid chromatography-tandem mass spectrometry. Multivariable survey logistic regression was used to assess the associations between environmental antibiotics exposures and childhood obesity. After adjusting for potential confounders, increased odds of obesity were observed in children exposed to tetracycline (OR = 1.31, 95% CI: 1.09-1.57) and sulfamonomethoxine (OR = 1.43, 95% CI: 1-2.05). Comparing none (<LODs), low-, middle-, and high-exposure groups, the low- sulfamonomethoxine exposure was associated with an increased odds of obesity (OR = 1.91, 95% CI: 1.05-3.47). Higher odds of obesity were associated with middle-level exposures to tetracycline (OR = 1.96, 95% CI: 1.05-3.66), doxycycline (OR = 1.56, 95% CI: 1-2.46), and lincomycin (OR = 1.35, 95% CI: 1.05-1.74). However, no significant association was found in any high-level antibiotic exposure groups. The significant associations were mainly observed in boys. The associations between environmental antibiotics exposures and childhood obesity are non-linear. Low- to middle-level exposures to certain environmental antibiotics may increase the risk of childhood obesity, especially in boys.