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


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


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
Li-Min
LM
Sun
Department of Nuclear Medicine, E-DA Hospital, Kaohsiung, Taiwan.
Ming-Chia
MC
Lin
Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
Chih-Hsin
CH
Muo
Graduate Institute of Clinical Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan; Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan.
Ji-An
JA
Liang
Graduate Institute of Clinical Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
Fung-Chang
FC
Sung
Graduate Institute of Clinical Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan; Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan. Electronic address: dr.kaochiahung@gmail.com.
Chia-Hung
CH
Kao
D000328:Adult; D000368:Aged; D000505:Alopecia / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D016022:Case-Control Studies; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013624:Taiwan; D013964:Thyroid Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
Androgenic alopecia (AA); National Health Insurance system; Population-based study; Thyroid cancer