Background: Epidemiologic studies have shown consistent associations between obesity and increased thyroid cancer risk, but, to date, no studies have investigated the relationship between thyroid cancer risk and obesity-related single-nucleotide polymorphisms (SNP).
Methods: We evaluated 575 tag SNPs in 23 obesity-related gene regions in a case-control study of 341 incident papillary thyroid cancer (PTC) cases and 444 controls of European ancestry. Logistic regression models, adjusted for attained age, year of birth, and sex were used to calculate ORs and 95% confidence intervals (CI) with SNP genotypes, coded as 0, 1, and 2 and modeled continuously to calculate P(trend).
Results: Nine of 10 top-ranking SNPs (P(trend) < 0.01) were located in the FTO (fat mass and obesity associated) gene region, whereas the other was located in INSR (insulin receptor). None of the associations were significant after correcting for multiple testing.
Conclusions: Our data do not support an important role of obesity-related genetic polymorphisms in determining the risk of PTC.
Impact: Factors other than selected genetic polymorphisms may be responsible for the observed associations between obesity and increased PTC risk.