Life Course Cumulative BMI Burden From Childhood to Adulthood and Risk of Metabolic Multimorbidity: A 36-Year Prospective Cohort Study

OBJECTIVE: To examine the associations between cumulative BMI burden from childhood to adulthood and the risk of adult metabolic multimorbidity. RESEARCH DESIGN AND METHODS: This prospective cohort study used data from the Hanzhong Adolescent Hypertension Study (1987-2023). A total of 2,446 participants with at least two BMI measurements in both childhood (6-18 years) and adulthood (19-52 years) were included. Cumulative BMI exposure was quantified using total and incremental area under the curve (AUC). Outcomes included metabolic multimorbidity, defined as the presence of two or more or three or more metabolic diseases, specifically hypertension, diabetes, dyslipidemia, elevated liver enzymes/bilirubin, and kidney damage. RESULTS: Higher total and incremental BMI AUC during childhood, adulthood, and over the life course were consistently associated with an increased risk of adult metabolic multimorbidity (two or more diseases). For total AUC, odds ratios (ORs) ranged from 1.51 to 2.59 (all P < 0.05); for incremental AUC, ORs ranged from 1.94 to 4.33 (all P < 0.05). Compared with total AUC, incremental AUC showed a stronger association with metabolic multimorbidity in childhood (OR 4.33 [95% CI 2.93, 6.40] vs. 1.51 [1.17, 1.95], respectively). Conversely, total AUC exhibited a stronger association in adulthood than in childhood (OR 2.51 [2.08, 3.04] vs. 1.94 [1.62, 2.31]). Furthermore, the associations for adulthood and life course BMI AUC were significantly stronger in males than in females (P for interaction