Thyroid cancer and its associated factors: A population-based case-control study

Abstract

Considering the rising incidence and mortality of thyroid cancer (TC) worldwide, the aim of our study was to determine the risk factors for TC in a province with the highest incidence of TC in the country located at the South of Iran. A population-based case-control study was performed on 708 participants (361 new cases and 347 controls). The case participants were selected from the Iranian National Cancer Registry database. Frequency matched for gender and age, and the control participants were selected randomly from the neighborhood of the cases. Based on the results of multiple logistic regression analysis, benign thyroid diseases (eg, hyperthyroidism OR_yes/no = 14.06, 95% CI: 5.13-38.51), family history of TC (OR_yes/no = 3.54, 95% CI: 1.51-8.26), radiation exposure of the head (OR_yes/no = 1.92, 95% CI: 1.03-3.60), family history of thyroid diseases (OR_yes/no = 1.76, 95% CI: 1.19-2.62) and family history of other types of cancer (OR_yes/no = 1.67, 95% CI: 1.01-2.74), significantly increased the risk of developing TC. On the other hand, high blood pressure (OR_yes/no = 0.35, 95% CI: 0.19-0.64), higher education (OR_{college/illiterate} = 0.54, 95% CI: 0.30-0.96), consumption of unsaturated fat (OR_{unsaturated/saturated} = 0.59, 95% CI: 0.39-0.87) and being married (OR_{married/single} = 0.60, 95% CI 0.37-0.98) were found to be protective factors. Some community-based interventions, for example, reduction in radiation exposure and screening members of families with underlying thyroid diseases may help in preventing or early diagnosis of TC. More studies on the health effects of local herbs are highly recommended.

Keywords: case-control study; risk factors; thyroid cancer.