Sex dimorphic associations between oxidative stress and adiposity in early childhood

Abstract Objective Oxidative stress is suspected in the development of obesity. We sought to evaluate the relationship between oxidative stress and obesity/adiposity in early childhood, and explore potential sex dimorphic associations. Design Nested case–control study. Methods In a study of 120 pairs of children with overweight/obesity vs. optimal weight in the Shanghai Birth Cohort, we assessed oxidative stress (urinary biomarker 8-isoprostane) in relation to obesity/overweight and adiposity indicators [body mass index (BMI, z-score), body fat mass (BFM), and percent body fat (PBF)] in early childhood (age 4 years). Results Urinary 8-isoprostane concentrations were higher in overweight/obese vs. optimal weight children in males (2.23 ± 1.68 vs. 1.60 ± 1.01 ng/mg creatinine, P = .001), but similar in females (1.74 ± 1.81 vs. 1.81 ± 0.94, P = .26). Positive correlations were observed in 8-isoprostane with BMI z-score (r = 0.34, P < .001), BFM (r = 0.28, P < .001), and PBF (r = 0.26, P = .002) in males, while no correlation was observed in females. Adjusting for maternal and child factors, one log unit increment in urinary 8-isoprostane concentration was associated with a 0.72 (95% CI .31-1.13) increase in BMI z-score, 1.02 (0.12-1.19) kg increase in BFM, and 3.09% (0.01%-6.17%) increase in PBF in males, respectively. Conclusions Oxidative stress levels were elevated in overweight/obesity children, and positively correlated with adiposity in males only, suggesting sex-dimorphic associations between oxidative stress and adiposity/obesity in early childhood.