Association of Metabolic Health and Central Obesity with the Risk of Thyroid Cancer: Data from the Korean Genome and Epidemiology Study.

ABSTRACT

BACKGROUND: It is unknown whether the risk of thyroid cancer differs among metabolically healthy/unhealthy, normal-weight, or obese women. We aimed to assess the association of metabolic health and obesity with thyroid cancer risk. METHODS: The Korean Genome and Epidemiology Study is a population-based prospective cohort study. Data were obtained from 173,343 participants (age ≥40 years) enrolled from 2004 to 2013. Obese participants were those with body mass index (BMI) ≥25 kg/m2. Participants with abnormalities in three of these indices were considered metabolically unhealthy triglycerides, blood pressure, high-density lipoprotein cholesterol (HDL-cholesterol), waist circumference (WC), and fasting glucose levels. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for thyroid cancer risk associated with metabolic health and obesity. RESULTS: Compared with nonobese women without metabolic abnormalities, metabolically unhealthy women, either normal weight or obese, had an increased risk of thyroid cancer [HR (95% CI) = 1.57 (1.02-2.40) and 1.71 (1.21-2.41), respectively). Significant association was not observed in men. Thyroid cancer risk was higher among nonobese women with high WC [≥85 cm; HR (95% CI) = 1.62 (1.03-2.56)] than in nonobese women with low WC, and in obese women with low HDL-cholesterol [<50 mg/dL; HR (95% CI) = 1.75 (1.26-2.42)] compared with nonobese women with high HDL-cholesterol. CONCLUSIONS: Metabolically unhealthy women or women with central adiposity may be at an increased thyroid cancer risk despite normal BMI. IMPACT This study suggests that women with central obesity and metabolic abnormality despite normal BMI may constitute a target group for thyroid cancer prevention and control programs.