Obesity and risk of differentiated thyroid cancer: A large-scale case-control study

Objective Recently, the incidence of thyroid cancer as well as obesity has dramatically increased worldwide. Whether obesity contributes to the development of differentiated thyroid cancer (DTC) remains controversial. We evaluated the relationship between anthropometric measurements and DTC risk. Design/Patients/Measurements A large frequency-matched case-control study based on hospital data was performed. A total of 10 668 DTC patients and 11 858 controls were enrolled. Body mass index (BMI), body surface area (BSA) and body fat percentage (BF%) were calculated. An unconditional logistic regression model was applied. Results The univariate analysis showed a significant increase in DTC risk with increased height, weight, BMI, BSA and BF%. The multivariate analysis also showed a positive relationship. Based on the Chinese BMI (CN-BMI) classification, for women of all ages, the ORs for DTC risk in overweight and obesity were 1.151 (1.037-1277) and 1.292 (1.092-1.528), respectively. For men under 50, the ORs were 1.221 (1.014-1.469) and 1.520 (1.202-1.923), respectively, but the ORs for men over 50 were not significant. Additionally, BSA showed a significant association with DTC risk for both sexes under 50 (P = .02 and P < .001). BF% remained significant only for women under 50 (P = .003). However, for both sexes over 50, neither BSA nor BF% was significantly associated with DTC risk. Based on The World Health Organization BMI (WHO-BMI) classification, for all women and men over 50, the results were consistent with CN-BMI. For men under 50, BF%, but not BMI, showed a significant association with DTC risk. Conclusion BMI, BSA and BF% were positively correlated with the risk of DTC, which was potentially affected by age and sex.