Hironori Imano

Carotid Intima-Media Thickness and Plaque Characteristics as a Risk Factor for Stroke in Japanese Elderly Men

Background and Purpose— Few cohort studies have examined the association of carotid intima-media thickness (IMT) and plaque characteristics with the risk of stroke in apparently healthy persons. We examined the relationship of carotid IMT and the surface, morphology, and calcification of carotid plaques with the incidence of stroke among Japanese men. Methods— Carotid IMT and plaque were evaluated bilaterally with ultrasonography in 1289 men aged 60 to 74 years without a previous stroke or coronary heart disease. In this cohort, the subsequent incidence of stroke was investigated. Results— During the 4.5-year follow-up, 34 strokes occurred. The multivariate-adjusted relative risk (95% CI) for the highest versus lowest quartiles of maximum IMT of the common carotid artery (CCA; ≥1.07 versus ≤0.77 mm) was 3.0 (1.1 to 8.3) for stroke. The combination of CCA and internal carotid artery (ICA) wall thickness was a better predictor of the risk of stroke than was CCA wall thickness alone. Men with a plaque, defined as a focal wall thickness of ≥1.5 mm, in the ICA had a 3-fold higher risk of stroke than those without a plaque, and the plaque surface irregularity further increased the stroke risk. A significant excess risk of stroke was confined to men with an uncalcified plaque. Conclusions— Increased IMT of the CCA and an uncalcified plaque in the ICA, as assessed by ultrasonography, are risk factors for stroke in elderly Japanese men.

Linoleic Acid, Other Fatty Acids, and the Risk of Stroke

Background and Purpose— The role of serum fatty acids as a risk factor for stroke and stroke subtypes is largely unknown. Methods— A prospective nested case-control study of Japanese 40 to 85 years of age was conducted through the use of frozen serum samples from 7450 participants in cardiovascular risk surveys collected from 1984 to 1989 for 1 community and 1989 to 1992 for the other 2 communities. By the end of 1998, we identified 197 incident strokes whose subtypes were confirmed by imaging studies. Three controls per case were selected by matching for sex, age, community, year of serum storage, and fasting status. Results— Compared with controls, total (n=197), hemorrhagic (n=75), and ischemic (n=122) strokes had similar proportions of n3 polyunsaturated fatty acids, lower proportions of linoleic and arachidonic acids, and higher proportions of saturated and monosaturated acids, determined by gas chromatography. The multivariate odds ratios associated with a 1-SD increase in linoleic acid (5%) after adjustment for hypertension, diabetes, serum total cholesterol, and other cardiovascular risk factors were 0.72 [95% confidence interval (CI), 0.59 to 0.89] for total stroke, 0.66 (95% CI, 0.49 to 0.88) for ischemic stroke, 0.63 (95% CI, 0.46 to 0.88) for lacunar infarction, and 0.81 (95% CI, 0.59 to 1.12) for hemorrhagic stroke. The respective odds ratios for saturated fatty acids (4%) were 1.13 (95% CI, 1.05 to 1.65), 1.35 (95% CI, 1.01 to 1.79), 1.44 (95% CI, 1.03 to 2.01), and 1.21 (95% CI, 0.82 to 1.80). Further adjustment for other fatty acids attenuated these relations, but the relation between linoleic acid and risk of ischemic stroke remained statistically significant. Conclusions— A higher intake of linoleic acid may protect against ischemic stroke, possibly through potential mechanisms of decreased blood pressure, reduced platelet aggregation, and enhanced deformability of erythrocyte cells.

Metabolic Syndrome and the Risk of Ischemic Heart Disease and Stroke Among Japanese Men and Women

Background and Purpose— Limited evidence was available on the metabolic syndrome and risk of cardiovascular disease in Asia. The purpose of this study is to examine the association of the metabolic syndrome and risk of ischemic cardiovascular disease in Japanese men and women. Methods— We conducted an 18-year prospective study of 9087 Japanese people aged 40 to 69 years (3595 men and 5492 women), initially free of ischemic heart disease or stroke. During follow-up, there were 116 (74 men and 42 women) cases of ischemic heart disease and 256 (144 men and 112 women) ischemic strokes. Metabolic syndrome was defined by the modified criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATPIII), with the presence of ≥3 of the following factors: (1) serum triglycerides ≥1.69 mmol/L (150 mg/dL); (2) HDL-cholesterol <1.03 mmol/L (40 mg/dL) for men and <1.29 mmol/L (50 mg/dL) for women; (3) glucose ≥6.11 mmol/L (110 mg/dL) fasting or ≥7.77 mmol/L (140 mg/dL) nonfasting, or on treatment; (4) blood pressure ≥130/85 mm Hg or medication use, and (5) body mass index ≥25.0 kg/m2. Results— For both sexes, high blood pressure, high triglycerides and low HDL cholesterol were associated with increased risks of ischemic heart disease or stroke after adjustment for cardiovascular risk factors. A dose-response relationship was found between the number of metabolic risk factors and incidence of these cardiovascular end points. The multivariable hazard ratio (95% CI) associated with metabolic syndrome was 2.4 (1.4 to 4.0) in men and 2.3 (1.2 to 4.3) in women for ischemic heart disease, and 2.0 (1.3 to 3.1) and 1.5 (1.0 to 2.3), respectively, for ischemic stroke. The contribution of metabolic syndrome to the risks was independent of serum total cholesterol levels but stronger among smokers. Conclusions— The metabolic syndrome is a major determinant of ischemic cardiovascular disease among middle-aged Japanese men and women, in particular among smokers.

The joint impact on being overweight of self reported behaviours of eating quickly and eating until full: cross sectional survey.

Objective To examine whether eating until full or eating quickly or combinations of these eating behaviours are associated with being overweight. Design and participants Cross sectional survey. Setting Two communities in Japan. Participants 3287 adults (1122 men, 2165 women) aged 30-69 who participated in surveys on cardiovascular risk from 2003 to 2006. Main outcome measures Body mass index (overweight ≥25.0) and the dietary habits of eating until full (lifestyle questionnaire) and speed of eating (validated brief self administered questionnaire). Results 571 (50.9%) men and 1265 (58.4%) women self reported eating until full, and 523 (45.6%) men and 785 (36.3%) women self reported eating quickly. For both sexes the highest age adjusted mean values for height, weight, body mass index, and total energy intake were in the eating until full and eating quickly group compared with the not eating until full and not eating quickly group. The multivariable adjusted odds ratio of being overweight for eating until full was 2.00 (95% confidence interval 1.53 to 2.62) for men and 1.92 (1.53 to 2.40) for women and for eating quickly was 1.84 (1.42 to 2.38) for men and 2.09 (1.69 to 2.59) for women. The multivariable odds ratio of being overweight with both eating behaviours compared with neither was 3.13 (2.20 to 4.45) for men and 3.21 (2.41 to 4.29) for women. Conclusion Eating until full and eating quickly are associated with being overweight in Japanese men and women, and these eating behaviours combined may have a substantial impact on being overweight.

Prospective Study of Depressive Symptoms and Risk of Stroke Among Japanese

BACKGROUND AND PURPOSE We sought to examine the relationship between depressive symptoms and the incidence of stroke among Japanese men and women. METHODS A 10.3-year prospective study on the relationship between depressive symptoms and the incidence of stroke was conducted with 901 men and women aged 40 to 78 years in a rural Japanese community. Depressive symptoms were measured at baseline with the use of the Zung Self-Rating Depression Scale (SDS). The incidence of stroke was ascertained under systematic surveillance. RESULTS During the 10-year follow-up, 69 strokes (39 ischemic strokes, 10 intracerebral hemorrhages, 10 subarachnoid hemorrhages, and 10 unclassified strokes) occurred. Age- and sex-adjusted prevalence of mild depression (SDS scores >/=40) at baseline was 25% among subjects with incident stroke and 12% among subjects without stroke (P<0.01). Persons with SDS scores in the high tertile had twice the age- and sex-adjusted relative risk of total stroke as those with scores in the low tertile. The excess risk was confined to ischemic stroke. After we adjusted for body mass index, systolic blood pressure level, serum total cholesterol level, cigarette smoking, current treatment with antihypertensive medication, and history of diabetes mellitus, these relative risks remained statistically significant for total stroke (1.9; 95% CI, 1.1 to 3.5) and ischemic stroke (2.7; 95% CI, 1.2 to 6.0). CONCLUSIONS Depressive symptoms predict the risk of stroke, specifically ischemic stroke among Japanese.

Trends in the Incidence of Coronary Heart Disease and Stroke and Their Risk Factors in Japan, 1964 to 2003 : The Akita-Osaka Study

A continuous decline in mortality and morbidity from coronary heart disease (CHD) has been documented in the U.S. ([1–4][1]). This decline is accompanied by a reduction in serum total cholesterol levels, which has been attributed to improvements in medical care and community-based prevention

Serum Total Homocysteine Concentrations and Risk of Stroke and Its Subtypes in Japanese

Background—To date, no prospective studies have examined the association between serum homocysteine levels and the risk of stroke and stroke subtypes in Asian populations. Methods and Results—A prospective, nested, case-control study of Japanese subjects 40 to 85 years of age was conducted by using frozen serum samples from 11 846 participants in cardiovascular risk surveys collected from 1984 to 1995 for one community and 1989 to 1995 for the other two communities. By the end of 2000, we identified 150 incident strokes, the subtypes of which were confirmed by imaging studies. Three control subjects per case were selected by matching for sex, age, community, year of serum storage, and fasting status. Serum total homocysteine levels were measured by high-performance liquid chromatography. Compared with control subjects, total (n=150), hemorrhagic (n=52), and ischemic (n=98) strokes had higher geometric mean values of total homocysteine and higher proportions of homocysteine ≥11.0 μmol/L. The multivariate odds ratios (95% CI) for highest (≥11.0 μmol/L) versus lowest quartiles (<7.0 μmol/L) of homocysteine after adjustment for body mass index, smoking, alcohol intake, hypertension, serum total cholesterol, and other cardiovascular risk factors were 2.99 (1.51 to 5.93) for total stroke, 3.89 (1.60 to 9.46) for ischemic stroke, 3.36 (1.27 to 8.90) for lacunar infarction, and 1.63 (0.44 to 6.00) for hemorrhagic stroke. The respective multivariate odds ratios associated with a 5-μmol/L increase in homocysteine were 1.40 (1.09 to 1.80), 1.52 (1.07 to 2.14), 1.48 (1.01 to 2.18), and 1.10 (0.76 to 1.59). The excess risk of total and ischemic strokes did not vary significantly according to sex, age, smoking status, or hypertensive status. Conclusions—High total homocysteine concentrations were associated with the increased risk of total stroke, more specifically ischemic stroke and lacunar infarction, among Japanese men and women.

Effects of Habitual Alcohol Intake on Ambulatory Blood Pressure, Heart Rate, and Its Variability Among Japanese Men

We sought to examine effects of habitual alcohol intake on ambulatory blood pressure (BP), heart rate (HR), and HR variability among Japanese men. Subjects were 539 men aged 35 to 65 years from rural and urban communities. Ambulatory BP and HR were monitored with an automated, portable, noninvasive multibiomedical recorder. Power spectral analysis of the RR intervals on the ECG was performed every 5 minutes. Compared with nondrinkers, moderate drinkers (alcohol intake 23 to 45 g/d) and heavy drinkers (alcohol intake ≥46 g/d) showed higher age- and field-adjusted mean values of systolic and diastolic BPs during the morning and while awake, but there were no differences in BPs over 24-hour periods and while asleep among the alcohol intake categories. Alcohol intake was positively associated with mean values of sleep-morning differences and daytime variability in BPs, HRs while awake and asleep, and low frequency:high frequency ratio while asleep. The results were virtually unchanged after adjustment for body mass index, smoking, and diabetes mellitus. Compared with the nondrinkers, age- and field-adjusted odds ratios of the morning BP surge (excess elevation of BP in the morning: morning systolic BP minus sleep systolic BP ≥37 mm Hg) for light (alcohol intake 0 to 22 g/d), moderate, and heavy drinkers were 0.96 (95% CI: 0.34 to 2.78), 1.68 (95% CI: 0.64 to 4.38), and 2.73 (95% CI: 1.12 to 6.67), respectively. Habitual alcohol intake was associated with increased BP in the morning, HR while awake and asleep, and sympathetic activity while asleep, which may explain some of the mechanisms of the relationship between heavy alcohol intake and risk of cardiovascular diseases.

Adult Mortality Attributable to Preventable Risk Factors for Non-Communicable Diseases and Injuries in Japan: A Comparative Risk Assessment

Using a combination of published data and modeling, Nayu Ikeda and colleagues identify tobacco smoking and high blood pressure as major risk factors for death from noncommunicable diseases among adults in Japan.

Trends for Blood Pressure and Its Contribution to Stroke Incidence in the Middle-Aged Japanese Population The Circulatory Risk in Communities Study (CIRCS)

BACKGROUND AND PURPOSE Hypertension is a major risk factor for stroke. However, a substantial decrease in blood pressure levels in Japanese during the past 3 decades may have reduced contributions of hypertension to risk of stroke. The population attributable fraction, the percentage of outcomes attributable to exposure, of blood pressure for the incidence of stroke was investigated during 3 survey periods between 1963 and 1994 by means of a population-based cohort study. METHODS We explored 3 cohort data of residents aged 40 to 69 years in 4 Japanese communities in 1963 to 1971 (n=5439), 1975 to 1984 (n=9945), and 1985 to 1994 (n=11 788) baseline surveys. Mean follow-up period for each cohort was 10 years. RESULTS Higher blood pressure levels were associated with higher risk of stroke. Positive associations were also observed even within nonhypertension levels. From the first to the third cohorts, the blood pressure category with a majority of stroke incidence shifted from severe or moderate hypertension to mild hypertension. The population attributable fraction of the severe hypertension category in the first, second, and third cohorts were 20%, 14%, and 9%, respectively, and those of the moderate hypertension category were 19%, 24%, and 11%, respectively, whereas those of the mild hypertension category were 17%, 26%, and 23%, respectively. The results were similar when participants on antihypertensive medication were excluded. CONCLUSIONS The higher risk of stroke incidence with higher blood pressure levels even in nonhypertension categories and the shift of stroke burden from severe/moderate hypertension to mild hypertension support the early management of hypertension and primary prevention of high blood pressures for the prevention of stroke.