The Role of Modifiable Risk Factors in the Development of Thyroid Cancer

Abstract

Objectives: Evaluate the role of modifiable patient risk factors including tobacco use, secondhand smoke exposure, alcohol consumption, and body mass index (BMI) in the development of thyroid cancer. Methods: Retrospective study comparing Midwest thyroid cancer patients from our multicenter Thyroid Tumor and Cancer Registry and Midwest controls without personal history of cancer. Descriptive statistics were created from detailed questionnaires, thyroid cancer type, and odds ratios were reported for significant associations. Results: There were 469 cancer patients and 425 controls. The thyroid cancer group included 406 papillary, 47 follicular, 13 medullary, and 3 anaplastic cancers. Comparing all cancer patients with controls, there was no association between smoking and thyroid cancer ( P = .18). Living or working with smokers was associated with increased cancer risk (odds ratio [OR] = 1.36, 95% confidence interval [CI] 1.04-1.77). Compared with never drinking, current drinking was associated with reduced cancer risk (OR = 0.48, 95% CI 0.31-0.75) as was consuming 1 to 2 drinks daily compared with drinking <1 drink daily (OR = 0.55, 95% CI 0.36-0.85). Consuming >2 drinks daily was not associated with cancer risk ( P = 0.26, 95% CI 0.47-1.22). There was no association between BMI and papillary cancer, except in patients older than 45 years with a BMI >30 (OR = 1.87, 95% 1.20-2.92). Conclusions: Our data suggest that secondhand smoke exposure is a risk factor for developing thyroid cancer and mild alcohol consumption is associated with reduced risk of developing thyroid cancer. BMI over 30 may be associated with thyroid cancer development for individuals over 45 years old.