OBJECTIVES: The global prevalence of overweight and obesity among children and adolescents have been soaring during the last decades. Little evidences exist on the association between adolescent overweight and obesity and medical expenditures in adulthood. We aim to evaluate the association between adolescent body mass index (BMI) and medical expenditures 20 to 40 years later.

METHODS: In this retrospective cohort study, we used data of a large state-mandated health provider in Israel (Maccabi Healthcare Services, MHS). We identified MHS members, born since 1950 with a BMI measurement in late adolescence taken as part of mandatory physical examination at age ~17 during pre-recruitment to the Israeli Defense Forces. The cohort's yearly medical expenditures were evaluated during 2010-2021, at the ages of 35, 45 or 55 years. Generalized linear model with gamma distribution with log link was used to estimate the association between BMI categories and medical expenditures. BMI categories were defined as underweight (<18.5 kg/m²), normal (18.5-<25 kg/m²; reference), overweight (25-<30 kg/m²), obese class I (30-<35 kg/m²) and class II+III (35+ kg/m²). Total direct costs of medical services utilized in MHS were adjusted to national gross domestic product in 2021 and to international dollars (I$) by using purchasing power parity.

RESULTS: We identified 496,404 patients who met the inclusion criteria (268,790 (54.1%) were males). Mean medical expenditures for patients with underweight (14.4%), normal (74.7%), overweight (9.2%), obese class I (1.5%) and obese class II+III (0.2%) at the of age 45 years were 1018I$, 1105I$, 1483I$, 1818I%, 1785I$ respectively. Compared to patients with normal weight, overweight (rate ratio[RR]:1.34; 95%CI 1.32-1.37), obese class I (RR:1.65; 95%CI 1.58-1.72) and obese class II+III (RR:1.62; 95%CI 1.45-1.80) were associated with increased medical expenditures. Similar RRs were observed at ages 35 and 55 years.

CONCLUSIONS: Overweight and obesity in adolescence are associated with increased medical expenditures during adulthood.