Dietary Intake of Saturated Fatty Acids and Incident Stroke and Coronary Heart Disease in Japanese Communities

The JPHC Study

Kazumasa Yamagishi; Hiroyasu Iso; Yoshihiro Kokubo; Isao Saito; Hiroshi Yatsuya; Junko Ishihara; Manami Inoue; Shoichiro Tsugane

Disclosures

Eur Heart J. 2013;34(16):1225-1232. 

In This Article

Abstract and Introduction

Abstract

Aims Although dietary saturated fatty acids (SFA) are considered atherogenic, associations between SFAs intake and stroke and coronary heart disease are still debated. We sought to test the hypothesis that SFA intake is associated inversely with risk of stroke and its subtypes and positively with coronary heart disease among Japanese, whose average SFA intake is lower than that of Westerners.

Methods and results The Japan Public Health Center-based prospective Study involves two subcohorts: Cohort I, aged 45–64 in 1995 and followed-up through 2009, and Cohort II, aged 45–74 in 1998 and followed-up through 2007. A total of 38 084 men and 43 847 women were included in this report. Hazards ratios for incident total stroke, ischaemic stroke, intraparhenchymal haemorrhage, subarachnoid haemorrhage, myocardial infarction, and sudden cardiac death across quintiles of dietary SFAs were examined. We found inverse associations between SFA intake and total stroke [multivariable hazard ratio (95% confidence interval) for the highest vs. lowest quintiles = 0.77 (0.65–0.93), trend P = 0.002], intraparenchymal haemorrhage [0.61 (0.43–0.86), P for trend = 0.005], and ischaemic stroke [0.84 (0.67–1.06), trend P = 0.08], primarily for deep intraparenchymal haemorrhage [0.67 (0.45–0.99), P for trend = 0.04] and lacunar infarction [0.75 (0.53, 1.07), trend P = 0.02]. We also observed a positive association between SFAs intake and myocardial infarction [1.39 (0.93–2.08), trend P = 0.046] primarily among men. No associations were observed between SFAs intake and incidence of subarachnoid haemorrhage or sudden cardiac death.

Conclusions In this Japanese population, SFAs intake was inversely associated with deep intraparenchymal haemorrhage and lacunar infarction and positively associated with myocardial infarction.

Introduction

Saturated fatty acid (SFA) intake has been considered to be atherogenic, and it is suggested that reducing SFA intake prevents atherosclerotic diseases.[1] Yet, recent meta-analyses have indicated that greater dietary intake of SFA per se may not be associated with increased risk of coronary disease,[2,3] though another meta-analysis showed that replacing SFA intake with polyunsaturated fatty acids (PUFA) intake was inversely associated with coronary events.[4] Several cohort studies, but not all, have reported an inverse association between dietary SFA and risk of ischaemic stroke and/or intraparenchymal haemorrhage.[3] Thus, the role of SFA intake in the development of both coronary diseases and stroke remains under debate.

Compared with Westerners, Asian people traditionally consume less SFA-containing foods, as shown in the Seven Countries Study[5] and also in later studies.[6,7] The low SFA intake among Asians has been believed to be one reason why they have lower mortality from coronary disease than Westerners. However, no prospective studies have been conducted to examine the association between dietary SFA intake and incident stroke and coronary disease in Asians, except for intraparenchymal haemorrhage.[6]

The Japan Public Health Center-based prospective (JPHC) Study is one of the largest prospective studies in Japan, with a systematic incidence registry of cardiovascular disease. An advantage of this study included enough number of population to study subtypes of stroke (i.e. subarachnoid, deep or lobar intraparenchymal haemorrhage and lacunar, large-artery occlusive or embolic infarction), which is often hard to study in Western cohorts. The population is also unique in that they have very low SFA intake and high stroke and low coronary disease incidence. Our hypotheses were that low SFA intake is associated with elevated risk of deep intraparenchymal haemorrhage and lacunar infarction, and high SFA intake with elevated risk of coronary heart disease.

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