Association of body mass index and the risk of papillary thyroid carcinoma / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the correlation between body mass index (BMI) and the occurence of papillary thyroid carcinoma (PTC) among the patients with thyroid nodules. Methods This cross-sectional study collected the data of 4 350 patients with thyroid nodules who underwent thyroidectomy in our hospital from January 1994 to December 2013. The patients were divided into normal weight (BMI 18.50~23.9 kg/m 2), overweight (BMI 24.0~27.9 kg/m 2), and obese (BMI≥28.0 kg/m 2) groups according to BMI, as well as benign nodules and papillary thyroid carcinoma groups based on their pathological finding. The differences of age-sex composition, nodule diameter, TSH level, overweight and obese constituent ratio between two groups were also analyzed. Logistic regression method was used to evaluate the risk factors of PTC. Results (1) Compared with the benign nodule group, there was a higher proportion of patients under the age of 40 years (34.1% vs 19.5%, P<0.01) in PTC group, with smaller tumour diameters [ 1.0 (0.7-2.0) cm vs 3.0 (2.0-4.0) cm, P<0.01]and higher TSH levels [ 1.9 (1.2-3.0) mU/L vs 1.6 (0.9-2.5) mU/L, P<0.01]. (2) The proportion of obese patients was higher in PTC group than that in the benign nodule group (28.7% vs 20.7%, P<0.01) among male patients. While the difference was not found among female patients. (3) Stratification analysis according to gender and age showed that the proportion of overweight (49.4% vs 44.1%, P<0.05) or obese (26.5% vs 15.3%, P<0.01) in PTC group was higher than that of benign nodule group among male patients aged≤40 years and the proportion of obese patients in PTC group was higher than that of benign nodule group (30.8% vs 22.2%, P<0.01) among male patient aged 41 to 65 years. (4) A multivariate analysis indicated that overweight (OR=4.947) and obesity (OR=7.648) were all independent risk factors for PTC (P<0.01) among male patients aged≤40 years. Conclusion Overweight and obesity are associated with higher PTC risk for male patients aged 40 years or less.