White matter changes on magnetic resonance imaging: a risk factor for stroke in an African population?

White matter changes are frequently observed incidental findings in elderly individuals. Many studies in Europe and the United States have assessed the association of white matter changes with stroke and other diseases. No similar study has been conducted in sub-Saharan Africa, where risk factors for stroke differ. Our objective was to explore the association between severity of white matter changes (based on visual rating scales) and stroke in a Nigerian population.

Magnetic resonance imaging (MRI) scans of 50 patients were retrospectively assessed and scored using 3 different visual rating scales (by Fazekas et al, Scheltens et al, and Manolio et al). The scores were classified as either mild or severe. Clinical indications and MRI scan results were classified into vascular (stroke) and nonvascular groups. The association between severity of white matter changes and stroke on MRI was explored using the Student t test, the Chi-square test, and multiple regression analysis at an alpha level of .05.

White matter changes were consistently and significantly more severe in patients with stroke than in patients without stroke (.01 ≤ P < .001; odds ratios 4.58 and 13.3, respectively) using the 3 visual rating scales. This finding was independent of age and gender as confirmed by regression analysis (adjusted odds ratios 4.8 and 9.2; .015 ≤ P ≤ .003).

Our findings suggest that severity of white matter changes in Nigerians may be a significant risk factor for stroke independent of age and gender. Prospective larger studies will be required to confirm its role in predicting stroke and stroke recurrence independent of other vascular risk factors, such as hypertension, diabetes, and cardiac diseases.