PopulationsHumans4,825 participantsCohort study

Thyroid antibodies linked to heart risk in younger adults

Across 4,825 adults followed for 14.8 years on average, thyroid antibodies were linked to cardiovascular risk in participants under 40 but not in those aged 40 and older.

Figure 1 from Journal of Translational Autoimmunity — Figure 1Shaker et al.

Journal of Translational Autoimmunity6 Oct 2026, 18:09 BST

In a prospective cohort study, researchers followed 4,825 adults aged 20 or older who had no cardiovascular disease at the start. The team examined thyroid peroxidase antibodies, immune proteins that target thyroid tissue, and recorded 576 cardiovascular events over an average follow-up of 14.8 years. Across the overall cohort, antibody levels were not associated with cardiovascular risk, and the range of likely values included no difference. However, age modified this association. In exploratory analyses, higher antibody levels were associated with increased cardiovascular disease risk in participants younger than 40 years, with an adjusted hazard ratio of 1.35. In participants aged 40 and older, there was no association. The link in younger participants also remained in those with normal thyroid function.

Why it matters

Cardiovascular disease risk increases with age, yet how thyroid autoimmunity relates to heart risk across different life stages has been controversial. The authors suggest that age may be a potentially important modifier of the association between thyroid autoimmunity and cardiovascular disease.

Caveats

Because the study was observational, it cannot show that thyroid antibodies cause heart disease events. Furthermore, the age-stratified analyses were exploratory and hypothesis-generating, meaning the results require validation in other cohorts.