Modifiable Risk Factors and Thyroid Cancer

Objective To evaluate the association between modifiable patient risk factors including tobacco use, alcohol consumption, body mass index (BMI), and thyroid cancer. Study Design Retrospective study with chart review. Setting Midwest university hospital. Subjects and Methods Retrospective study comparing Midwest patients with thyroid cancer from our Thyroid Tumor and Cancer Registry with Midwest controls without a personal history of cancer. Descriptive statistics were created from patient questionnaires and chart reviews. Odds ratios (ORs) were reported for significant associations. Results There were 467 patients with cancer and 255 controls. The thyroid cancer group included 404 papillary, 47 follicular, 13 medullary, and 3 anaplastic cancers. When comparing all patients with cancer with controls, smoking more than 100 lifetime cigarettes was associated with a reduced cancer risk (OR, 0.68; 95% confidence interval [CI], 0.50-0.94). Secondhand smoke exposure did not show a statistically significant relationship to thyroid cancer. Compared with never drinking, current drinking was associated with a reduced cancer risk (OR, 0.46; 95% CI, 0.29-0.73) as was consuming 1 to 2 drinks daily compared to drinking <1 drink daily (OR, 0.58; 95% CI, 0.34-0.89). There was no difference between median BMI at age 20 years, lifetime maximum BMI, or current BMI between patients with cancer and controls. Conclusion Our data showed no positive correlation between tobacco use, alcohol consumption, or obesity and thyroid cancer risk. Our data suggest that tobacco use and mild alcohol consumption may be associated with a slightly reduced risk of thyroid cancer. There was no association between BMI and thyroid cancer in our study population.