Association of birth weight with general obesity, central obesity, and MASLD in a nationally representative sample of US adolescents: A cross-sectional study from NHANES 1999 to 2020

Birth weight (BW) may influence subsequent risk of obesity and metabolic dysfunction-associated steatotic liver disease (MASLD); however, the conclusions are controversial and lack exploration in US adolescents. We aimed to explore the association of BW (including low BW [LBW], normal BW [NBW], and high BW [HBW]) with body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and fatty liver index (FLI), as well as general obesity, central obesity, and MASLD, in adolescents using National Health and Nutrition Examination Survey 1999 to 2020. BW was obtained from participants' self-reports. Obesity and MASLD were diagnosed based on their respective specific cutoff values in adolescents. Multivariate linear regression and logistic regression analyses were used to explore these associations and calculate β and odds ratios. A total of 6867 adolescent participants were enrolled. After adjusting for all confounders, BW was positively associated with BMI, WC, WHtR, and FLI (β of 0.639, 1.872, 0.005, and 2.128, respectively). Compared to NBW, HBW was associated with significantly increased BMI, WC, WHtR, and FLI (β of 1.205, 3.387, 0.012, and 4.745, respectively), whereas LBW was not. Similarly, compared to NBW, HBW was associated with significantly increased odds of general obesity, central obesity (as defined by WC/WHtR, respectively), and MASLD (odds ratios 2.629, 1.713, 1.618, and 1.960, respectively). However, LBW was not significantly associated with obesity and steatosis. Race/ethnicity partially influenced these associations. HBW, but not LBW, was associated with increased prevalence of general obesity, central obesity, and MASLD among U.S. adolescents. These findings underscore that adolescents with HBW are at risk for obesity and steatosis and may require early screening and intervention, especially among other Hispanic ethnic groups.