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

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 ORyes/no = 14.06, 95% CI: 5.13‐38.51), family history of TC (ORyes/no = 3.54, 95% CI: 1.51‐8.26), radiation exposure of the head (ORyes/no = 1.92, 95% CI: 1.03‐3.60), family history of thyroid diseases (ORyes/no = 1.76, 95% CI: 1.19‐2.62) and family history of other types of cancer (ORyes/no = 1.67, 95% CI: 1.01‐2.74), significantly increased the risk of developing TC. On the other hand, high blood pressure (ORyes/no = 0.35, 95% CI: 0.19‐0.64), higher education (ORcollege/illiterate = 0.54, 95% CI: 0.30‐0.96), consumption of unsaturated fat (ORunsaturated/saturated = 0.59, 95% CI: 0.39‐0.87) and being married (ORmarried/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. What's new? Incidence and mortality of thyroid cancer is increasing worldwide, for reasons that are not fully known. Here, to better understand thyroid cancer risk in the general population, the authors examined possible risk factors in Kohgiluyeh and Boyer‐Ahmad, a province in Southern Iran with very high thyroid cancer incidence. Analyses identified individual and family history of thyroid disease, family history of thyroid cancer and other cancers, and radiation exposure to the head to be important risk factors for thyroid cancer. The findings suggest that routine screening of individuals with these risk factors could facilitate prevention and early detection of thyroid cancer. [ABSTRACT FROM AUTHOR]