Family Ties May Shape Hashimoto Thyroiditis Risk

Medscape

12-06-2025

The odds of developing Hashimoto thyroiditis (HT) were significantly elevated in first-, second-, and third-degree relatives of patients with HT, with female relatives having a disproportionately higher likelihood. Of note, the odds of developing HT were elevated among spouses of patients.
METHODOLOGY:
Relatives of patients with HT are at an increased risk for HT; however, studies have primarily focused on first-degree relatives and often employed very small sample sizes.
Researchers conducted a retrospective case-control study using genealogical and medical data from a Utah-based database (1996-2021) to estimate the risk for HT in relatives across various degrees of relatedness.
They included 92,405 adult HT probands (73% women; 96% White individuals) and 184,810 matched control individuals, along with 2,960,650 first-, second-, and third-degree relatives of HT probands and 5,730,159 relatives of control individuals.
TAKEAWAY:
Relatives of patients with HT were at an increased risk for the condition, with the highest odds observed for first-degree relatives (odds ratio [OR], 1.77; 95% CI, 1.74-1.80), followed by second-degree (OR, 1.23; 95% CI, 1.22-1.27) and third-degree (OR, 1.11; 95% CI, 1.10-1.12) relatives.
The risk for HT was an additional 2.2- to 2.6-fold higher in female relatives of patients with HT than overall estimates, across all degrees of relatedness.
Among first-degree relatives, sons of men with HT had a markedly elevated risk for HT (OR, 2.36; 95% CI, 2.10-2.65).
Wives of men with HT and husbands of women with HT were at an increased likelihood of developing HT, suggesting the effect of a shared environment.
IN PRACTICE:
'These findings also have clinical implications, as understanding familial clustering of HT can help healthcare providers identify individuals at higher risk, especially those with affected FDRs [first-degree relatives]. This knowledge could lead to earlier monitoring and intervention, improving disease management,' the authors of the study wrote.
SOURCE:
This study was led by Melissa Bujnis, PhD, Department of Human Genetics, University of Utah, Salt Lake City. It was published online in The Journal of Clinical Endocrinology & Metabolism .
LIMITATIONS:
Reliance on diagnostic codes may have introduced misclassification bias, particularly in cases of transient hypothyroidism or misdiagnosed HT. Variations in diagnostic practices across clinics may have introduced heterogeneity in the sample. Individuals with a family history of HT might be more likely to receive diagnosis or seek medical attention, potentially introducing ascertainment bias.
DISCLOSURES:
Partial support for the datasets in the database was provided by the University of Utah, Huntsman Cancer Institute, National Institutes of Health (NIH). This study received support from NIH, NCRR, and Utah Department of Health and Human Services and the University of Utah. The authors reported no relevant conflicts of interest.