Obesity is a risk factor for thyroid cancer in a large, ultrasonographically screened population

Abstract

Objective: Obesity is a well-known risk factor for many cancers, including those of the esophagus, colon, kidney, breast, and skin. However, there are few reports on the relationship between obesity and thyroid cancer. We conducted this study to determine whether obesity is a risk factor for thyroid cancer by systematically screening a selected population by ultrasonography. Design and methods: We obtained data from 15 068 subjects that underwent a routine health checkup from 2007 to 2008 at the Health Screening and Promotion Center of Asan Medical Center. Thyroid ultrasonography was included in the checkup, and suspicious nodules were examined by ultrasonography-guided aspiration. Those with a history of thyroid disease or family history of thyroid cancer were excluded from this study. Results: In total, 15 068 subjects, 8491 men and 6577 women, were screened by thyroid ultrasonography. Fine-needle aspiration cytology was performed in 1427 of these patients based on the predefined criteria and thyroid cancer was diagnosed in 267 patients. The prevalence of thyroid cancer in women was associated with a high BMI (per 5 kg/m 2 increase) (odds ratios (OR)Z1.63, 95% CI 1.24-2.10, P!0.001), after adjustment for age, smoking status, and TSH levels. There was no positive correlation between the prevalence of thyroid cancer in men and a high BMI (ORZ1.16, 95% CI 0.85-1.57, PZ0.336). There was no association between age, fasting serum insulin, or basal TSH levels and thyroid cancer in either gender. Conclusions: Obesity was associated with a higher prevalence of thyroid cancer in women when evaluated in a routine health checkup setting. This association between risk factor and disease was unrelated to serum insulin and TSH levels. Additional studies are needed to understand the mechanism(s) behind the association of obesity with thyroid cancer risk.

Anthropometric Factors and Thyroid Cancer Risk by Histological Subtype: Pooled Analysis of 22 Prospective Studies

“…BMI is a widely used measure of adiposity but provides no information on the amount of lean versus fat mass or central versus peripheral body fat (51). Waist circumference and weight gain are more direct measures of central (visceral) adiposity and body fat mass, respectively.…”

MECHANISMS IN ENDOCRINOLOGY: The crosstalk between thyroid gland and adipose tissue: signal integration in health and disease

“…A systematic review of prospective observational studies showed a positive association between BMI categories at diagnosis and the risk of developing DTC (HRZ1.18 (95% CI, 1.03-1.35) for a 5 kg/m 2 increase) in both sexes and young adults (age range, 18-20 years) (145). More recently, a cross-sectional study has demonstrated that BMI is a significant predictor of DTC in women (OR, 1.63; 95% CI, 1.24-2.10) but not in men (OR, 1.16; 95% CI, 0.85-1.57) (146). Thus, it is conceivable to speculate that obesity might predispose to DTC, at least in females.…”

The influence of the environment on the development of thyroid tumors: a new appraisal

“…There are reports of a negative association between smoking habit and obesity in the risk of thyroid cancer (Guignard et al 2007, Kitahara et al 2011, Han et al 2013. A report relating different associations between smoking and thyroid function and size showed an increased risk of Graves' disease (GD; Graves' hyperthyroidism and Graves' ophthalmopathy) and nontoxic goiter (multinodularity) and a decreased risk of Hashimoto's disease (thyroid antibodies and autoimmune hypothyroidism) and DTC (PTC and FTC) (Wiersinga 2013).…”