Women with alopecia exhibit a higher risk for thyroid cancer: a nationwide cohort study

Several studies have investigated the relationship between alopecia and prostate cancer. However, little information is available regarding the relationship between alopecia and the risk of cancers in women.

The purpose of this study was to evaluate the possible association between alopecia and thyroid cancer among Taiwanese women.

We used data from the National Health Insurance system of Taiwan. The alopecia cohort comprised 4534 women, and each woman was randomly frequency matched by age, index month, and index year with 4 women from the general population without alopecia. A Cox proportional hazard regression analysis with Bonferroni correction was conducted to estimate the effects of alopecia on the risk of thyroid cancer.

In women with alopecia, the overall risk for developing cancer was 22% higher than for subjects without alopecia, but the difference was not significant [hazard ratio (HR) = 1.22, 97.5% confidence interval (97.5% CI) = 0.87-1.70]. However, the risk for developing thyroid cancer among women with alopecia was significantly higher (HR = 2.39, 97.5% CI = 1.05-5.42). Further analyses determined that the alopecia group had a higher incidence of Graves' disease, but not Hashimoto thyroiditis.

Although alopecia did not significantly increase cancer risks in women, we found that Taiwanese women with alopecia had a higher risk of developing thyroid cancer that is unlikely to be related to underlying thyroid diseases.