Effects of Overweight on Risk of Thyroid Nodules in Children and Adolescents: The Fukushima Health Management Survey.

CONTEXT:Examining how overweight/obesity impacts thyroid nodule development in children and adolescents by sex and age can speculate on the mechanism. OBJECTIVE:We examined whether overweight in children and adolescents are associated with thyroid nodule development by sex and age. DESIGN:Approximately 300,000 participants who underwent thyroid ultrasonography in the Fukushima Health Management Survey after a nuclear accident were enrolled. Those without nodules in the initial two examinations (1-3 and 4-5 years postaccident) were prospectively assessed for nodule development in the third examination (6-7 years postaccident) relative to baseline overweight status, with an average follow-up of 4.2 years. SETTING:A population-based prospective cohort study. PARTICIPANTS:The first and second thyroid examinations involved 299,939 and 237,691 participants, respectively, excluding those with thyroid nodules. After the third examination, 184,519 participants were finalized for analysis. MAIN OUTCOME MEASURES:Multivariable-adjusted odds ratios of new detected thyroid nodules for overweight participants compared with normal-weight participants. RESULTS:New thyroid nodules were detected in 660 participants. Being overweight was positively associated with thyroid nodules. The adjusted odds ratio (95% confidence interval) of thyroid nodules for overweight participants compared with other participants was 1.27 (1.04-1.57). Additionally, the multivariable-adjusted odds ratios for males and females with overweight were 1.21 and 1.32, respectively, and those for different age groups (0-9, 10-14, and 15-19 years) ranged from 1.17 to 1.75. CONCLUSIONS:Being overweight was associated with thyroid nodules in children and adolescents, mostly adolescent females, regardless of their proximity to the nuclear power plant.