Yuchi Naruse

High-Density Lipoprotein Cholesterol and Risk of Stroke in Japanese Men and Women The Oyabe Study

Background and Purpose— Evidence of an inverse relationship between serum high-density lipoprotein cholesterol (HDL-C) and the risk of stroke is sparse in Asians and in women. The purpose of this investigation was to examine the relationship in a long-term cohort study of Japanese men and women among whom stroke occurrence is higher than in Western countries. Methods— A prospective cohort study was performed involving 4989 participants (1523 men, 3466 women) 35 to 79 years of age at baseline with ≈10 years of follow-up in a rural area of Japan. End points included all stroke incidence and ischemic stroke incidence. Results— During follow-up, 132 participants developed stroke, including 81 ischemic stroke cases. Age-adjusted incidence rates per 10 000 person-years for all stroke in subjects with low HDL-C (<30 mg/dL [0.78 mmol/L]) were 103.4 in men and 49.3 in women, which were remarkably higher than in subjects with high HDL-C (≥60 mg/dL [1.56 mmol/L]) (26.4 in men and 15.5 in women). A similar relationship was observed for ischemic stroke. Multivariate-adjusted relative risks for all stroke incidence and ischemic stroke incidence were 2.89 (95% CI, 1.35 to 6.20) and 2.92 (95% CI, 1.17 to 7.32), respectively, for low versus high HDL-C participants. The relationships were independent of sex, age, body mass index, blood pressure, serum total cholesterol, alcohol consumption, and smoking. Conclusions— This 10-year follow-up study of Japanese men and women demonstrated that lower HDL-C levels were related significantly and independently to increased risk of all stroke incidence and ischemic stroke incidence.

Trends in stroke incidence and acute case fatality in a japanese rural area: The oyabe study

BACKGROUND AND PURPOSE Stroke mortality in Japan has significantly declined during recent decades. To determine the cause of this decrease, we studied the trends in stroke incidence and case fatality within 28 days after stroke in a rural area in Japan. METHODS We used a population-based registry during 1977-1991 in Oyabe, a rural area in the central part of Japan. The average population aged 25 years and older numbered 32 859 persons. Changes in age-standardized stroke incidence rate were calculated and compared between the 3 periods 1977-1981, 1982-1986, and 1987-1991. The 28-day case fatality rate was evaluated and also compared between the 3 periods by onset year. RESULTS The total number of strokes was 2068. The age-standardized incidence rate of all strokes decreased during the 15-year period, from 605 to 417 per 100 000 in men and from 476 to 329 per 100 000 in women. A marked decline was found during 1977-1986 but was not apparent during 1987-1991. Moreover, there was an increase in the group aged 75 years and older. The 28-day case fatality rates for all strokes improved from 18.0% to 14.2% in men and from 26.8% to 19.1% in women during the observation period. CONCLUSIONS These data indicate that declines in the stroke incidence and the 28- day case fatality have been associated with a marked decrease in stroke-related mortality in Japan.

Gender differences in the association between anthropometric indices of obesity and blood pressure in Japanese.

To investigate which of four anthropometric variables of obesity has the strongest association with blood pressure (BP), and to investigate whether there are gender differences in these relationships in Asian adults, we evaluated the associations of four anthropometric variables, body mass index (BMI), waist circumference, waist-to-hip ratio and waist-to-height ratio, with BP and the prevalence of hypertension in a cross-sectional study. A total of 4,557 employees of a metal-products factory in Toyama, Japan (2,935 men and 1,622 women, aged 35 to 59 years) were included in the study. Waist circumference in men and BMI in women had the strongest associations with BP. As for the age-adjusted rate ratio (RR) of the prevalence of hypertension for one standard deviation increase in each anthropometric variable, RR was the highest for waist circumference in men (RR, 1.44; 95% confidence interval [CI], 1.31–1.58), and for BMI in women (RR, 1.61; 95% CI, 1.38–1.88). The associations of waist circumference in men and BMI in women remained significant after adjustment for each of the other variables. The associations of waist-to-height ratio with BP and the prevalence of hypertension were a little weaker than those of waist circumference for both men and women. In conclusion, among four anthropometric variables of obesity—i.e., BMI, waist circumference, waist-to-hip ratio, and waist-to-height ratio—waist circumference had the strongest association with BP and the prevalence of hypertension in men and BMI had the strongest association with BP and hypertension in women. Waist circumference in men and BMI in women should be given more importance in the screening of and guidelines on hypertension in Asians.

Evaluation of the effects of shift work on nutrient intake: a cross-sectional study.

Evaluation of the Effects of Shift Work on Nutrient Intake: A Cross‐sectional Study: Yuko Morikawa, et al. Department of Epidemiology and Public Health, Kanazawa Medical University—The aim of this study was to investigate the effects of shift work on nutrient intakes, including macronutrient intake and micronutrient intake, in a large sample size. The study population included 2,254 male manual workers, 20–59 yr of age, employed in a factory. A self‐administered diet history questionnaire was used. The subjects were classified into 3 groups according to their work schedule: (i) fixed day workers; (ii) shift workers without midnight shifts; and (iii) shift workers with midnight shifts. The nutrient intakes of the groups were compared by age group. There was a significant difference in nutrient intakes between subjects aged 20–29 yr and those aged 30 yr and over. Among subjects aged 20–29 yr, the energy density value for saturated fat and the energy adjusted intakes of calcium, potassium, vitamin A, and vitamin B1 were the lowest among shift workers with midnight shifts. Among subjects aged 30 yr and over, the total energy intake was the highest among shift workers with midnight shifts; the difference was significant compared to fixed day workers. Shift workers with midnight shifts had the highest intake of cereals among subjects 30 yr of age and older. In conclusion, there were no significant differences in nutrient intakes between fixed day workers and shift workers without midnight shift. Shift work, particularly midnight shift work, affected nutrient intake. The impact of shift work on nutrient intakes differed by age and the type of shift work.

Comparison of Four Blood Pressure Indexes for the Prediction of 10-Year Stroke Risk in Middle-Aged and Older Asians

Information has been sparse on the comparison of 4 blood pressure (BP) indexes (systolic BP [SBP], diastolic BP [DBP], pulse pressure [PP], and mean BP [MBP]) in relation to long-term stroke incidence, especially in middle-aged and older Asian people. A prospective cohort study was performed in 4989 Japanese (1523 men and 3466 women) aged 35 to 79 at baseline with 10 years of follow-up. End points included stroke incidence (total, ischemic, and hemorrhagic). Multivariate-adjusted hazard ratios with a 1-SD higher value for each BP index were determined by Cox proportional hazard analyses; Wald &khgr;2 tests were used to compare the strength of relationships. Analyses were also done for each of 4 age-gender groups consisting of men and women aged 35 to 64 and 65 to 79 years. During follow-up, 132 participants developed stroke. Adjusted hazard ratios for all strokes were 1.68 for SBP, 1.72 for DBP, and 1.80 for MBP, which were higher than that for PP (1.34). SBP and DBP were related positively to stroke risk after adjustment of each other. PP was not the strongest predictor in any age-gender groups among 4 BP indexes. In men aged 65 to 79 years, SBP showed the strongest relationship to all stoke risk (hazard ratio 1.62) among 4 BP indexes. In women aged 65 to 79 years, hazard ratios for all strokes were 2.48 for MBP, 2.46 for DBP, 2.25 for SBP, and 1.57 for PP. The long-term incident stroke risk of high BP in Asians should be assessed by SBP and DBP together, or by MBP, not by PP.

Association between long working hours and sleep problems in white-collar workers

The purpose of this study is to examine the association between long work hours and sleep disturbance among white‐collar workers. We evaluated 1510 male white‐collar full‐time employees, between the ages of 18 and 59 years, using a comprehensive sleep quality questionnaire, the Pittsburgh Sleep Quality Index (PSQI). All subjects worked in a light metal products factory in Japan. The mean number of monthly overtime work hours was determined using data from the previous 6 months from timecard records. Subjects were divided into five groups based on quintiles of the mean number of monthly overtime work hours: <26 h month−1; ≥26 but <40; ≥40 but <50; ≥50 but <63; and >63. Leisure time physical activity, drinking habits just before sleep, presence of family/partner and health status were used as confounding factors in the multiple regression model. The prevalence of short sleep hours, impairment of sleep efficiency and daytime dysfunction among seven components of PSQI increased, in a dose–response relationship, with overtime work hours. The prevalence of high global score (>5.5 points) was highest in workers with overtime hours ≥50 h week−1. The odds ratios after adjustment for confounding factors for high global score using less than 26 h as a reference group were 1.67 for workers with ≥50 h and <63 h, and 1.87 for workers with 63 h and more. To conclude, the present results suggest that long work hours correlate with reduced sleep quality in a dose–response manner.

Relationship of alcohol consumption to 7-year blood pressure change in Japanese men.

Objective To determine the association of alcohol consumption with years-long blood pressure (BP) change, as well as baseline BP, adjusted for potential confounders. Design A prospective cohort study. Setting A metal-products factory in Toyama, Japan. Participants A total of 3900 men aged 20–59 years. Main outcome measures BP was measured annually for 7 years after the baseline examination. The generalized estimating equation method was used to analyze the relationship of alcohol consumption to baseline BP and average annual BP change, adjusting for age, yearly weight, work-related factors, and lifestyle factors, including the frequency of intake of 22 food groups. Results The baseline systolic BP after multivariate adjustment was 3.9 and 5.0 mmHg higher in drinkers consuming 200–299 and ≥ 300 g alcohol/week, respectively, than in non-drinkers (P < 0.001). The annual increase in systolic BP was 0.44 mmHg greater in drinkers consuming ≥ 300 g/week than in non-drinkers after adjustment for age and weight change (P < 0.001), where the increase over 7 years was estimated to be 3.08 mmHg greater. Even after being adjusted for the frequency of intake of 22 food groups, drinkers consuming ≥ 300 g/week showed a 0.33 mmHg greater annual increase in systolic BP than non-drinkers (P = 0.022). Baseline diastolic BP was significantly associated with alcohol consumption, but annual BP change was not. Conclusions An alcohol intake ≥ 300 g/week was associated with significantly greater annual BP increase, and baseline BP was significantly higher in drinkers consuming ≥ 200 g/week. It is necessary to limit alcohol intake to less than 200 g/week to prevent hypertension.

Dietary Intake of Fatty Acids and Serum C-reactive Protein in Japanese

BACKGROUND Inflammation has been established as a risk factor for cardiovascular diseases. The relationships of polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids to inflammation are still controversial in Western populations. The relationships are not clear in Japanese whose intake of seafood-based long-chain n-3 PUFAs is high. METHODS We conducted a cross-sectional epidemiologic study in the Japanese population (1,556 men and 1,461 women aged 35-60). Serum high sensitivity C-reactive protein (CRP) was measured, and intakes of 7 specific fatty acids (% of energy) were evaluated by a validated self-administered dietary history questionnaire. RESULTS CRP was significantly and inversely related to the intakes of oleic acid (p=0.008) and α -linolenic acid (p=0.026) in women after adjustment for confounding factors. A multiple regression analysis showed that, especially in the middle tertile of long-chain n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid) intake, CRP was inversely related to the intake of oleic acid and linoleic acid in both sexes and to the intake of α -linolenic acid in women. CONCLUSION Intakes of oleic acid, linoleic acid, and α -linolenic acid would reduce serum CRP, especially when the intake of long-chain n-3 PUFAs is at a moderate level in Japanese.

Burnout and Risk Factors for Arteriosclerotic Disease: Follow-up Study

Burnout and Risk Factors for Arteriosclerotic Disease: Follow‐up Study: Kazuyo Kitaoka‐Higashiguchi, et al. Department of Public Health, Kanazawa Medical University

Dietary glycemic index and risk of type 2 diabetes mellitus in middle-aged Japanese men

This cohort study investigated the association between dietary glycemic index (GI), glycemic load (GL), and the incidence of type 2 diabetes mellitus in middle-aged Japanese men, and the effect of insulin resistance and pancreatic B-cell function on the association. Participants were 1995 male employees of a metal products factory in Japan. Dietary GI and GL were assessed using a self-administered diet history questionnaire. The incidence of diabetes was detected in annual medical examinations over a 6-year period. The association between GI, GL, and the incidence of diabetes was evaluated using Cox proportional hazards models. During the study, 133 participants developed diabetes. Age- and body mass index-adjusted hazard ratios across the GI quintiles were 1.00 (reference), 1.62, 1.50, 1.68, and 1.80; and those of GL were 1.00 (reference), 1.07, 1.48, 0.95, and 0.98. The hazard ratio for the highest GI quintile was significantly greater than that for the lowest quintile. The influence of GI was more pronounced in the lowest insulin resistance subgroups. GI and pancreatic B-cell function were independently associated with the incidence of type 2 diabetes mellitus; participants with low B-cell function and the highest tertile of GI had the highest risk of diabetes. Dietary GI is associated with the incidence of diabetes in middle-aged Japanese men. GI and B-cell function were independently associated with incidence of diabetes.