Hypothyroidism vs Hyperthyroidism Associated With Intracranial Aneurysm Risk

Hypothyroidism is associated with an increased risk for unruptured intracranial aneurysm, according to study findings published in Thyroid.

Although the majority are asymptomatic, intracranial aneurysms can lead to life-threatening complications if ruptured. Previous research findings suggest a relationship between abnormal thyroid function and increased risk for cerebrovascular disease, but the association between intracranial aneurysms and thyroid function remains unclear.

To assess the relationship between hyperthyroidism and hypothyroidism and intracranial aneurysm development, researchers conducted a nested case-control study using data from the Korean National Health Insurance Service-National Sample Cohort. Participants older than 20 years of age with diagnosed unruptured intracranial aneurysm were matched to a control participant according to age and sex.

The final analysis included a total of 5335 participants with intracranial aneurysm and 80,025 control group participants. Among all participants, the average age was 60.4 years (SD, 11.9) and 31.5% were men.

The researchers identified associations between higher risk for unruptured intracranial aneurysm and:

• Tobacco use (odds ratio [OR], 1.31; 95% CI, 1.20-1.43);
• Antihypertensive medication usage (OR, 2.09; 95% CI, 1.96-2.23); and,
• Hypothyroidism (OR, 1.55; 95% CI, 1.34-1.79).

Risk for unruptured intracranial aneurysm was not associated with alcohol consumption, thyroid cancer, or hyperthyroidism.

After adjusting for confounding, the researchers still observed an association between hypothyroidism and unruptured intracranial aneurysm (adjusted OR, 1.46; 95% CI, 1.26-1.69). This association was stronger among women (adjusted OR, 1.48; 95% CI, 1.27-1.73) compared with men (adjusted OR, 1.26; 95% CI, 0.75-2.11).

The researchers also noted an association between hyperthyroidism and reduced incidence of unruptured intracranial aneurysm (adjusted OR, 0.71; 95% CI, 0.54-0.93). This association was also more significant among women (adjusted OR, 0.64; 95% CI, 0.47-0.87) compared with men (adjusted OR, 1.05; 95% CI, 0.61-1.83).

A longer duration of antithyroid medication use was associated with a decreased risk for intracranial aneurysm (adjusted OR, 0.35; 95% CI, 0.13-0.92).

Study limitations are potential misclassification bias due to the use of claims data, the lack of patient data on thyroid function, and missing information on tobacco and alcohol use. 

“Our findings suggest that the thyroid hormone status, rather than the underlying pathophysiology such as autoimmunity, may have influenced the development of [intracranial aneurysm],” the researchers concluded. 

This article originally appeared on Endocrinology Advisor