Prospective study of fat and protein intake and risk of intraparenchymal hemorrhage in women

Background - Dietary animal fat and protein have been inversely associated with a risk of intraparenchymal hemorrhage in ecological studies. Methods and Results - In 1980, 854 764 women in the Nurses' Health Study cohort, who were 34 to 59 years old and free of diagnosed cardiovascular disease and cancer, completed dietary questionnaires. From these questionnaires, we calculated fat and protein intake. By 1994, after 1.16 million person-years of follow-up, 690 incident strokes, including 74 intraparenchymal hemorrhages, had been documented. Multivariate-adjusted risk of intraparenchymal hemorrhage was higher among women in the lowest quintile of energy-adjusted saturated fat intake than at all higher levels of intake (relative risk [RR], 2.36; 95% CI, 1.10 to 5.09; P=0.03). For trans unsaturated fat, the corresponding RR was 2.50 (95% CI, 1.35 to 4.65; P=0.004). Animal protein intake was inversely associated with risk (RR in the highest versus lowest quintiles, 0.32; 95% CI, 0.10 to 1.00; P=0.04). The excess risk associated with low saturated fat intake was observed primarily among women with a history of hypertension (RR, 3.66; 95% CI, 1.09 to 12.3; P=0.04), but such an interaction was not seen for trans unsaturated fat or animal protein. These nutrients were not related to risk of other stroke subtypes. Dietary cholesterol and monounsaturated and polyunsaturated fat were not related to risk of any stroke subtype. Conclusions - Low intake of saturated fat and animal protein was associated with an increased risk of intraparenchymal hemorrhage, which may help to explain the high rate of this stroke subtype in Asian countries. The increased risk with low intake of saturated fat and trans unsaturated fat is compatible with the reported association between low serum total cholesterol and risk.