Association of adiposity with thyroid nodules: a cross-sectional study of a healthy population in Beijing, China

BACKGROUND: The relationship between thyroid nodules (TNs) and adiposity is controversial. This paper describes a cross-sectional investigation performed to determine the existence of any such relationship. To assess adiposity, body mass index (BMI) and visceral fat area (VFA) were utilized. METHODS: Between January 1, 2017 and March 3, 2019. Three thousand five hundred thirty four healthy people were examined using thyroid ultrasonography, visceral fat and anthropometric measurements, laboratory tests and questionnaire interview. Binary logistic regression analyses were used. RESULTS: Of the 3534 healthy subjects, 58.69% (2074/3534) of the subjects had TNs. A total of 55.91% (1976/3534) had BMI ≥ 25 kg/m(2) and 39.67% (1402/3534) had VFA ≥ 100 cm(2). After adjustment to address confounders, BMI-based overweight and obesity levels only correlated with higher risk TNs when used as a continuous variable (OR = 1.031, 95% CI: 1.008–1.055, P = 0.008), while VFA was both a continuous variable (OR = 1.003, 95% CI: 1.000–1.005, P = 0.034) and a categorical variable (OR = 1.198, 95% CI: 1.014–1.417, P = 0.034) associated with significantly elevated risk of TNs. Analyzing the subgroups, BMI ≥ 25 kg/m(2) (OR = 1.500, 95% CI: 1.110–2.026, P = 0.008) was significantly correlated with TN risk in individuals with TG ≥ 1.7 mmol/L. VFA ≥ 100 cm(2) correlated with the TN risk irrespective of age (< 50 years: OR = 1.374, 95% CI: 1.109–1.703, P = 0.004; ≥ 50 years: OR = 1.367, 95% CI: 1.063–1.759, P = 0.015) and in the following subgroups: women (OR = 4.575, 95% CI: 2.558–8.181, P = 0.000), FBG ≥ 6.1 mmol/L (OR = 1.522, 95% CI: 1.048–2.209, P = 0.027), and TG ≥ 1.7 mmol/L (OR = 1.414, 95% CI: 1.088–1.838, P = 0.010). CONCLUSIONS: Adiposity correlates with TNs. To assess TN risk in Chinese individuals, VFA is better than BMI.