[Association of Body Mass Index and Risk Stratification of Thyroid Nodules in a Multi-center Healthy Population].

Objective To investigate the relationship between body mass index(BMI)and risk levels of thyroid nodules in a multi-center healthy population. Methods A total of 6070 subjects were enrolled from five medical physical examination centers in China from January 2015 to December 2017. All the participants'general information and parameters were recorded. Thyroid nodules were detected by color Doppler ultrasonography. All ultrasound doctors received uniform training before study. Results Among all the subjects,5773(95.1%;with 4274 nodules identified in 2833 subjects)were from northern China and 297(4.9%,with 183 nodules identified in 158 subjects)from central China(χ²=1.923,P=0.092). The nodules were single in 1479 of 2991 subjects(49.4%)and multiple in 1512 subjects(50.6%). Nodules larger than 1 cm accounted for 13.3% and nodules smaller than 1 cm accounted for 86.7%. Compared with the non-thyroid nodule group,the thyroid nodule group had significantly more women(χ²=156.36,P=0.000),older age(t=-18.768,P=0.000),and higher fasting blood glucose(FBG) level(t=-3.808,P=0.000). Among all the nodules,the prevalence rates of benign,very-low-risk,low-risk,moderate risk,and high risk were 4.5%,6.6%,85.0%,0.1%,and 3.7%,respectively,according to the ATA guidelines. Notably,there were 4291 nodules at moderate or lower risks and 166 nodules at high risk. Compared with the former,patients with high-risk nodules had significantly lower BMI(χ²=25.161,P=0.000)and high FBG(t=3.357,P=0.000). Multivariate non-conditional Logistic regression showed low BMI(OR=2.900,95%CI:1.461-5.783,P=0.002)and high FBG level(OR=0.803,95%CI:0.675-0.955,P=0.013)were independent risk factors for high-risk nodules. Compared with subjects with normal weight or obese populations,subjects with low BMI had significantly higher detection rate of high-risk nodules(χ²=25.16,P=0.000). In ≥55 year-old group,significantly more high-risk nodules were detected in low BMI group(χ²=44.868,P=0.000). Conclusion Low weight is associated with high-risk thyroid nodules among people ≥55 years old.