Family Medicine
Partner With Us
Advertisement
From the Journals

Thyroid-Hair Loss Link Found in Genetic Study

A large-scale genetic analysis of over 410,000 patients revealed that hypothyroidism increased alopecia areata risk by 40% (OR=1.40), establishing the first causal link between these conditions through Mendelian randomization.

Conexiant

A Mendelian randomization analysis found causal relationships between specific thyroid disorders and alopecia areata.

In the study, published in Skin Research and Technology, investigators examined genetic data showing that hypothyroidism, Hashimoto's thyroiditis, and subacute thyroiditis influenced alopecia areata (AA) risk.

The two-sample Mendelian randomization study showed hypothyroidism increased the risk of AA (odds ratio [OR] = 1.4009815, 95% confidence interval [CI] = 1.1210399–1.750829, P = .003030698), as did Hashimoto's thyroiditis (OR = 1.396101, 95% CI = 1.030134–1.89208, P = .03144273). Subacute thyroiditis showed a different relationship with AA (OR = 0.732702, 95% CI = 0.604812–0.887634, P = .001483368).

The investigators analyzed genome-wide association studies (GWAS) data that included:

  • Hypothyroidism: 30,155 cases and 379,986 controls
  • Hashimoto's thyroiditis: 15,654 cases and 379,986 controls
  • Hyperthyroidism: 3557,cases and 456,942 controls
  • Graves' disease: 1,678 cases and 456,942 controls
  • Subacute thyroiditis: 418 cases and 187,684 controls.

The AA outcome data comprised 289 cases and 211,139 controls from the Finnish Genome Consortium.

The analysis identified specific single-nucleotide polymorphisms (SNPs) associated with each condition: 68 SNPs for hypothyroidism, 12 for Hashimoto's thyroiditis, 11 for hyperthyroidism, 4 for subacute thyroiditis, and 26 for Graves' disease.

Multiple sensitivity analyses, including MR-Egger regression, weighted median, inverse variance weighted (IVW), simple mode, and weighted mode methods supported the findings. Cochrane's Q test revealed no significant heterogeneity in the IVW results, whereas MR-Egger intercept testing showed no horizontal pleiotropy.

The study found no statistically significant causal relationships between hyperthyroidism or Graves' disease and AA risk.

The data came from public databases, with all participants being of European descent. The investigators used various MR analysis methods and conducted leave-one-out sensitivity analyses to verify result stability.

The authors declared having no competing interests.