Epidemiology

HBV not directly tied to increased stroke risk

Last Updated: 2007-05-04 17:41:21 -0400 (Reuters Health)

NEW YORK (Reuters Health) - The increased risk of stroke or myocardial infarction associated with hepatitis B appears to be secondary to liver dysfunction rather than a direct consequence of HBV seropositivity, Korean and British researchers report in the May issue of Stroke.

Dr. Yun-Mi Song of Sungkyunkwan University School of Medicine, Seoul and colleagues note that there have been conflicting findings on the possible association between hepatitis B virus surface antigen (HBsAg) seropositivity and cardiovascular disease.

To investigate, the researchers followed more than 521,000 men aged 30 to 64 years from 1990 to 1991.

After adjustment, HBsAg seropositivity was associated with a decreased risk of ischemic stroke and MI (odds ratios, 0.79 and 0.74) and an increased risk of hemorrhagic stroke (odds ratio 1.33).

Risks for stroke and MI were similar between HBsAg-seronegative and HBsAg-seropositive men in the absence of liver dysfunction.

Conversely, men with both HBsAg seropositivity and liver dysfunction had a higher risk of hemorrhagic stroke and lower risks of ischemic stroke and MI than HBsAg-seronegative men.

The findings, the researchers point out, do not support the hypothesis that HBV infection itself plays an important role in the etiology of MI or ischemic stroke through a proinflammatory effect.

"Rather," they conclude, "decreased coagulation status in HBV-associated chronic liver dysfunction appeared to increase the risk of hemorrhagic stroke while reducing the risk of ischemic stroke and MI."

Stroke 2007;38:1436-1441.