Association between obesity and thyroid nodules in children and adults living in iodine-sufficient areas: analysis of cross-sectional data from Tianjin, China.

OBJECTIVE

The main purpose of this study was to analyse the association between obesity and thyroid nodules in children and adults living in iodine-sufficient areas in China.

DESIGN

Analysis of data from two cross-sectional surveys.

SETTING AND PARTICIPANTS

921 children from 2016 to 2021 and 1505 adults from 2018 to 2021 living in iodine-sufficient areas from Tianjin, China were recruited.

OUTCOME MEASURES

Anthropometric measures including height and weight were taken, and body mass index (BMI) and body surface area (BSA) were calculated. Thyroid ultrasonography was performed to assess thyroid nodules. A multifactor logistic regression model and a restricted cubic spline model were used to analyse the association between BMI/BSA and thyroid nodules in children and adults.

RESULTS

Thyroid nodules were detected in 21.72% of children and 40.00% of adults. Compared with children in the low BMI and low BSA groups, children in higher BMI (=1.53, 95% CI 1.09 to 2.15) and higher BSA (=1.40, 95% CI 1.01 to 1.94) groups had significantly higher risks for thyroid nodules. High BMI and high BSA were also significantly associated with multiple thyroid nodules in children, with and 95% CIs of 1.51 (1.04 to 2.19) and 1.45 (1.01 to 2.08), respectively. The restricted cubic spline model indicated that the risk of thyroid nodules and multiple thyroid nodules in children increased with the increase of BMI-z-score and BSA. In adults, a high BSA (=1.34, 95% CI 1.01 to 1.77) was significantly associated with multiple thyroid nodules, but this association was not valid in the restricted cubic spline model.

CONCLUSION

Childhood obesity is associated with the risk of thyroid nodules; however, there is no clear association between adult obesity and thyroid nodules.