Circulating Fetuin-A and Risk of Ischemic Stroke in Women

BACKGROUND: Fetuin-A, a protein secreted primarily by the liver, has been associated with nonalcoholic fatty liver disease and insulin resistance. In a recent study, higher circulating fetuin-A was associated with cardiovascular events, particularly ischemic stroke. However, these data have not been replicated. METHODS: A nested case control design was used to examine the relationship between fetuin-A and ischemic stroke among female participants of the Nurses' Health Study. Fetuin-A was measured in blood samples collected and stored between 1989 and 1990. A total of 459 incident cases of ischemic stroke were identified and confirmed by medical records according to the National Survey of Stroke criteria between 1990 and 2006 and matched to 459 controls by age, race/ethnicity, date of sample collection, menopausal status, postmenopausal hormone use, and smoking status. The association between fetuin-A and ischemic stroke was modeled using conditional logistic regression. RESULTS: Circulating fetuin-A was higher in women (P < 0.01) who reported increased body mass index (BMI) of >= 25 kg/m(2), total cholesterol >= 200 mg/dL, high-sensitivity C-reactive protein >= 3 mg/L, and current hormone use at baseline. Significant partial Spearman correlations (P = 0.001), adjusted for matching factors, were found between measured concentrations of fetuin-A and triglycerides (r = 0.20), C-reactive protein (r = 0.14), and BMI (r = 0.15). Fetuin-A quartiles were not significantly associated with increased risk of incident ischemic stroke when adjusted for matching factors (relative risk, 1.03; 95% CI, 0.69-1.54, extreme quartiles); additional adjustment for lifestyle factors or cardiovascular disease risk factors and biomarkers did not alter results. CONCLUSIONS: In this sample of women, fetuin-A was not significantly associated with risk of ischemic stroke. Further research is needed to explore this association. (C) 2013 American Association for Clinical Chemistry