Case Finding Screening of First Degree Relatives of Patients with Hashimoto’s Thyroiditis.
Familial Risk of Hashimoto’s Thyroiditis Among First-Degree Relatives:
A Population-Based Study in Korea
Hyun Jung Kim,et al
Few small-scale studies have reported a genetic and familial predisposition in Hashimoto’s thyroiditis (HT), however, quantified familial risk estimates from population-level data are unavailable. We aimed to estimate the incidence and familial risk of HT among first-degree relatives (FDR) according to age,sex, and family relationships.
We conducted a population-based study in the general population of Korea from 2002 to 2017. Using the nationwide health insurance database, which has full population coverage & family relationship information, a cohort of 22 million individuals with blood-related FDR comprising 12 million families were followed up for a familial occurrence of HT. Age- and sex-adjusted incidence risk ratios (IRRs) were calculated in individuals with an affected FDR compared with those without an affected FDR.
Among 21,940,795 individuals, 234,912 had an HT-affected FDR, of whom 2425 familial cases developed HT with an incidence of 7.12/10,000 person-years. The familial risk for HT was 6.5-fold (95%confidence interval [CI]: 6.24–6.78) higher in individuals with versus without affected FDR. According to relationship, familial risks were IRR 102.71, IRR 7.80, IRR 5.54, and IRR 5.52 with an affected twin, sibling,mother, and father, respectively, and the corresponding incidence (/10,000 person-years) was 115.57, 10.66,5.73, and 5.91. Same-sex twins had three times higher risk of developing HT than opposite-sex twins (IRR121.01 vs. 21.46). The sex-specific familial risk was higher in males than females. The risks demonstrated age dependence, being higher in younger age groups.
This study represents the largest population-based study of familial HT risk in Asia. We demonstrated elevated familial risk of incident HT among FDR, but with lower magnitude as those observed in previous studies.
Familial risk increased with the degree of genetic relatedness among FDR indicating a prominent role of genetic factors in the familial aggregation of HT.
Elevated risks in the younger age groups should motivate clinicians to screen people with a family history, especially those<30 years
DR. Guttler’s comments:
- 22 million individuals with blood-related FDR comprising 12 million families were followed up for a familial occurrence of HT.
- Among 21,940,795 individuals, 234,912 had an HT-affected FDR, of whom 2425 familial cases developed HT with an incidence of 7.12/10,000 person-years.
- The familial risk for HT was 6.5-fold (95%confidence interval [CI]: 6.24–6.78) higher in individuals with versus without affected FDR.
- The risks demonstrated age dependence, being higher in younger age groups.
- Case finding for CHT is critical for those < 30 years old.
- In my practice I hand out a flyer to patients with CHT to have then inform there FDR’s they are at risk.
- Long standing untreated subclinical CHT without hypothyroidism in FDR’s who were not screened can lead to goiter growth,nodule formation, papillary thyroid cancer, and even the rare Thyroid lymphoma.
- Recent patient with untreated CHT for 10 years with a goiter presented this week with a thyroid lymphoma in Hashimoto’s thyroiditis.
- First degree relative screening evaluation available at my center.
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