Dietary Lipids and Incidence of Cerebral Infarction in a Japanese Rural Community.

Abstract

SummaryObjective: To assess the relationship between dietary lipids and incidence of cerebral infarction in a Japanese rural population. Design: A cohort study from July 1977 through December 1992. Setting: Akadani-Ijimino (A-I) district, Niigata Prefecture, Japan. Subjects and methods: All the residents, 1,182 men and 1,469 women, aged 40 years and over. Out of these members, 954 men and 1,329 women who were initially free of stroke completed a semiquantitative food frequency ques tionnaire in 1977, and were then subjected to a follow-up for 15.5 years. The occurrence of stroke was determined by the annual follow-up exam ination and registry. Dietary lipid was adjusted for total energy or fat intake by the residual method. Sex and age-stratified and blood pressure and atrial fibrillation-adjusted relative risk for cerebral infarction was estimated by the Cox proportional hazard model. Results: There were 75 new cases of cerebral infarction during the observation period. The relative risk for cerebral infarction was less than one in the highest quartile level of total fat, saturated fatty acids (S), Keys score and west ernized dietary pattern: 0.68-0.94. It ranged between 1.36 and 1.57 in the highest level of polyunsaturated (P), n-3 and n-6 fatty acids, and P/S ratio. Conclusion: This study suggests the possibility that the traditional Japanese diet, very low fat intake, was likely to increase the risk of stroke through the low level of serum cholesterol as an intermediary factor. Key Words dietary lipids, cerebral infarction, cohort study, serum cho lesterol, "diet-stroke" hypothesis According to the "diet-heart" hypothesis (1, 2), a high intake of saturated fatty acids and cholesterol and low intake of polyunsaturated fatty acids increase the 83 84 F. SEINO et al. level of serum cholesterol, and hypercholesterolemia results in the occurrence of coronary heart disease and stroke. In Japan, however, some ecological studies compared stroke incidence rates among several defined populations, and showed that the rates were inversely correlated with mean serum cholesterol and fat intake (3, 4). Afterwards, some cohort studies indicated that the level of serum cholester ol was inversely associated with the risk of stroke; particularly cerebral hemorrhage and cerebral infarction in perforating artery regions after adjustment for some confounding variables such as sex, age and blood pressure (5-7).To date, however, there have been few prospective studies on the relationship between dietary fat and stroke among Japanese in Japan. Using all of the residents aged 40 years and over in Akadani-Ijimino district (hereinafter referred to as A-I district), Shibata City, Niigata Prefecture, Japan, their dietary lipid intakes were assessed by a semiquantitative food frequency questionnaire in July 1977. Those who were initially free of stroke have been subjected to a follow-up ever since. In this report, we deal with the relationship of dietary lipid intake to the subsequent 15.5-year incidence of cerebral infarction which sho...

Age-Dependent Association of Apolipoprotein E Genotypes With Stroke Subtypes in a Japanese Rural Population

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“…32 Small vessel pathogenesis differs from the atheroma process in large vessels, and cholesterol may protect small vessel endothelium. 29,32,33 Thus, in the Honolulu Heart Program study, protein and fat from animal sources were risk factors for atherosclerosis in large arteries, but not in the small cerebral vessels. 28 Nevertheless, in spite of accumulated data on the protective effect of blood cholesterol level on stroke incidence or death, 34,35 we did not observe any significant correlation between dietary cholesterol and total serum cholesterol levels (correlation coefficientϭϪ0.01, Pϭ0.40).…”

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“…Third, in a 14-y prospective study (1983 to 1997) of 4,775 Japanese aged 40 to 69 y who participated in a single 24-h dietary recall survey, a low intake of saturated fat (approximately ,10 g/d) was found to be associated with increased risk of intraparenchymal hemorrhage after adjusting for known cardiovascular risk factors (7). No study found an association between saturated fat intake and risk of brain infarction (10).…”

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