Comment: does L-thyroxine prevent or cause stroke in hypothyroidism?
The association between overt hypothyroidism and atherosclerotic risk factors, especially hypertension and dyslipidemia, is clear. To date, only a few small and methodologically flawed epidemiologic studies have investigated the relationship between hypothyroidism and stroke, precluding definitive conclusions. In the current issue of Neurology®, Karch and Thomas(1) present a large well-designed case-control study investigating this relationship. They compared 34,907 patients with autoimmune thyroiditis on treatment with l-thyroxine and 149,632 matched individuals without autoimmune thyroiditis from a UK primary care electronic health record system. They found a slight increase in the risk of stroke in patients with autoimmune thyroiditis (adjusted relative risk = 1.10, 95% confidence interval: 1.01-1.20) compared with controls. Some of this increased risk of stroke was independent of cardiovascular risk factors.
From the Research Center on Thromboembolic Disorders and Antithrombotic Therapies (A.S.), Department of Clinical Medicine, University of Insubria, Varese, Italy; and Department of Internal Medicine (V.E.A.G.), Slotervaart Hospital, Amsterdam, the Netherlands.
Alessandro
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Squizzato
Victor E A
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Gerdes
D005260:Female; D006801:Humans; D008297:Male; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology*; D013967:Thyroiditis, Autoimmune / Q000150:complications* / Q000453:epidemiology*