The findings of Gillman et al1 reported in this issue of THE JOURNAL that lower levels of dietary fat are associated with a higher risk of ischemci stroke among men in the Framingham Heart Study are certainly intriguing and probably important. Although the same association has been observed in Asian2 and Asian American populations,3 this is the first such demonstration among Caucasians in a cohort study. Because lower levels of dietary fat lead to lower levels of blood cholesterol, the first instinct is to think of blood cholesterol as the mediating factor. It is true that very low levels of blood cholesterol have been consistently associated with hemorrhagic stroke.4 However, the findings of Gillman et al1 relate to ischemic stroke and persist after adjustment for blood cholesterol; this suggests that blood cholesterol is not part ofthe causal chain, if indeed there is a causal chain.
Sherwin R, Price TR. Fat ChanceDiet and Ischemic Stroke. JAMA. 1997;278(24):2185-2186. doi:10.1001/jama.1997.03550240075038