Child Body Mass Index and Health Care Costs in England.

Importance: In England, 27% of children aged 2 to 15 years live with overweight or obesity. However, national estimates of excess health care costs attributable to unhealthy weight status are lacking. Objective: To estimate health care costs associated with childhood weight status, stratified by sex, age, and ethnicity, in England. Design, Setting, and Participants: This retrospective cross-sectional study used 2014 to 2020 Clinical Practice Research Datalink Aurum data linked with Hospital Episode Statistics at general practices in England. Children aged 2 to 15 years with at least 1 body mass index (BMI) measurement recorded during a general practice visit between January 1, 2015, and March 30, 2019, for whom primary care and linked Hospital Episode Statistics data were available were studied. The analysis was conducted from December 11, 2023, to March 17, 2025. Exposure: BMI-derived weight status categories. Main Outcomes and Measures: Total health care costs were analyzed for the 1-year period before and after BMI measurement. Attributable health care costs were estimated using 2-part generalized linear models, adjusted for sex, age, ethnicity, socioeconomic status, and geographic region. Results: The study included the health care records of 268 231 unique children (mean [SD] age, 6.82 [2.66] years; 148 230 [55%] male; 4554 [2%] Bangladeshi, 16 708 [6%] Black, 7778 [3%] Chinese or other Asian, 7665 [3%] Indian, 10 875 [4%] Pakistani, 169 299 [63%] White, 10 886 [4%] multiracial, and 40 466 [15%] other or unknown). Before BMI measurement, health care costs were higher for children with overweight, obesity, and severe obesity but lower for children with underweight compared with children with healthy weight. After BMI measurement, costs were higher in children with underweight, overweight, obesity, and severe obesity compared with children with healthy weight. Severe obesity had the highest mean annual excess costs at £190 (95% CI, £77-£302) (US $274 [95% CI, US $111-US $435]) followed by underweight at £164 (95% CI, £69-£260) (US $236 [95% CI, US $99-US $374]). Health care costs varied by sex, age group, and ethnicity, although interactions were limited to specific BMI categories and covariate levels. The excess annual national health care cost attributable to overweight and obesity was £0.27 billion (95% CI, £0.12 billion to £0.43 billion) (US $0.39 billion [95% CI, US $0.17 billion to US $0.62 billion]). Conclusions and Relevance: In this cross-sectional study of children, health care costs were higher for nearly all unhealthy weight categories compared with healthy weight BMI measurement. These findings support the economic case for preventive and therapeutic interventions targeting unhealthy childhood weight and offer cost estimates for use in cost-effectiveness analyses.