Background: Few studies have evaluated the specific age period in childhood when the association of body mass index with adult hyperuricemia begins to be operative. This study aimed to examine the associations between body mass index in different childhood age periods and the risk of adult hyperuricemia in China.

Methods: The study cohort from the China Health and Nutrition Survey included 676 participants who were aged ≥ 18 years and had data on uric acid in 2009 with at least one measurement of body mass index in childhood surveys before 2009. There were 357, 365, 358, 427, and 432 observations in childhood age groups of ≤ 5 years, 6–9 years, 10–12 years, 13–15 years, and 16–18 years, respectively. Body mass index Z score was calculated based on 2000 Center for Disease Control and Prevention growth charts for the United States.

Results: Childhood body mass index Z scores measured at age ≤ 5 years, 6–9 years, 10–12 years, and 13–15 years had no statistical association with adult uric acid. In comparison, childhood body mass index Z scores measured at age 16–18 years were significantly associated with adult uric acid (β = 11.539, P = 0.007), and the strength of association was stronger in girls (β = 18.565, P = 0.002) than in boys (β = 9.209, P = 0.087). In addition, childhood body mass index Z scores measured at age 16–18 years were significantly associated with an increased risk of adult hyperuricemia (odds ratio = 1.323, 95% confidence interval = 1.003–1.746, P = 0.048), but not for other age groups.