Prospective Study of Fat and Protein Intake and Risk of Intraparenchymal Hemorrhage in Women
Hiroyasu Iso, MD; Meir J. Stampfer, MD; JoAnn E. Manson, MD; Kathryn Rexrode, MD; Frank B. Hu, MD; Charles H. Hennekens, MD; Graham A. Colditz, MBBS; Frank E. Speizer, MD; Walter C. Willett, MD From Channing Laboratory (H.I., M.J.S., J.E.M., K.R., G.A.C., F.E.S., W.C.W.) and the Division of Preventive Medicine (J.E.M., K.R.), Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Mass; Departments of Epidemiology (M.J.S., G.A.C., W.C.W.) and Nutrition (M.J.S., F.B.H., W.C.W.), Harvard School of Public Health, Boston, Mass; and University of Miami (C.H.H.), Miami, Fla.
Correspondence to Meir J. Stampfer, MD, Channing Laboratory, Brigham and Women’s Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115.
Background-Dietary animal fat and protein have been inversely associated with a risk of intraparenchymal hemorrhage in ecological studies.
Methods and Results?In 1980, 85 764 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.
Fat and Protein Intakes and Risk of Intraparenchymal Hemorrhage among Middle-aged Japanese
Hiroyasu Iso1,, Shinichi Sato2, Akihiko Kitamura2, Yoshihiko Naito2, Takashi Shimamoto2 and Yoshio Komachi2 1 Department of Public Health Medicine, Institute of Community Medicine, University of Tsukuba, Ibaraki-ken, Japan. 2 Osaka Medical Center for Health Science and Promotion, Osaka, Japan.
The authors examined the relation between low intakes of saturated fat and animal protein and risk of intraparenchymal hemorrhage in a 14-year prospective study (ending in 1997) of 4,775 Japanese aged 40-69 years who undertook a single 24-hour dietary recall. Compared with the highest quartile of energy-adjusted saturated fat intake (median, 17 g/day), multivariate relative risks, after adjustment for age, sex, community, total energy intake, and known cardiovascular risk factors, were 0.77 (95% confidence interval (CI): 0.42, 1.42) for the second quartile (12 g/day), 0.66 (95% CI: 0.34, 1.25) for the third quartile (8 g/day), and 0.30 (95% CI: 0.12, 0.71) for the lowest quartile (5 g/day); p for trend = 0.005. An inverse relation was observed among both hypertensives and nonhypertensives; the respective relative risks with a one standard deviation increase in saturated fat intake (15.4 g/day) were 0.72 (95% CI: 0.52, 1.00) and 0.36 (95% CI: 0.14, 0.95). Intake of animal protein tended to correlate inversely with risk; the relative risk with a one standard deviation increase in animal protein intake (17.6 g/day) was 0.79 (95% CI: 0.61, 1.02); p = 0.07. Results are similar to those recently reported for US women and together help to explain the high rate of this stroke subtype in Asian countries, where intakes of these nutrients are low.