Katsushi Yoshita

Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: the INTERMAP study.

Public health campaigns in several countries encourage population-wide reduced sodium (salt) intake, but excessive intake remains a major problem. Excessive sodium intake is independently related to adverse blood pressure and is a key factor in the epidemic of prehypertension/hypertension. Identification of food sources of sodium in modern diets is critical to effective reduction of sodium intake worldwide. We used data from the INTERMAP Study to define major food sources of sodium in diverse East Asian and Western population samples. INTERMAP is an international, cross-sectional, epidemiologic study of 4, 680 individuals ages 40 to 59 years from Japan (four samples), Peoples Republic of China (three rural samples), the United Kingdom (two samples), and the United States (eight samples); four in-depth, multipass 24-hour dietary recalls/person were used to identify foods accounting for most dietary sodium intake. In the Peoples Republic of China sample, most (76%) dietary sodium was from salt added in home cooking, about 50% less in southern than northern samples. In Japan, most (63%) dietary sodium came from soy sauce (20%), commercially processed fish/seafood (15%), salted soups (15%), and preserved vegetables (13%). Processed foods, including breads/cereals/grains, contributed heavily to sodium intake in the United Kingdom (95%) and the United States (for methodological reasons, underestimated at 71%). To prevent and control prehypertension/hypertension and improve health, efforts to remove excess sodium from diets in rural China should focus on reducing salt in home cooking. To avoid excess sodium intake in Japan, the United Kingdom, and the United States, salt must be reduced in commercially processed foods.

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.

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.

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.

Specific alcoholic beverage and blood pressure in a middle-aged Japanese population: The High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study

The purpose of this study was to clarify the effects of popular Japanese alcoholic beverages on blood pressure. We performed a cross-sectional study on 4335 Japanese male workers using baseline data from an intervention study. We defined six groups according to the type of alcoholic beverage that provided two-thirds of the subjects total alcohol consumption: beer, sake (rice wine), shochu (traditional Japanese spirits), whiskey, wine and others. The partial regression coefficients of daily alcohol intake (1 drink=11.5 g of ethanol) to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.87(P<0.001, standard error (s.e.)=0.09) and 0.77(P<0.001, s.e.=0.06), respectively. A comparison among the types of alcoholic beverages mainly consumed revealed significant differences in SBP and DBP. Both SBP and DBP were highest in the shochu group. However, an analysis of covariance adjusting for total alcohol consumption resulted in the disappearance of these differences. Although after adjustment for total alcohol consumption, the shochu group exhibited a significant positive association with ‘high-normal blood pressure or greater’ (odds ratio 1.43, 95% confidence interval 1.06–1.95) compared with the beer group, this significant relation disappeared after adjusting for the body mass index (BMI), urinary sodium and potassium excretion. The pressor effect, per se, of popular Japanese alcoholic beverages on blood pressure may not be different among the types of alcoholic beverages after adjusting for other lifestyle factors.

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.

The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study: study design and cardiovascular risk factors at the baseline survey.

In order to establish the methodology of a population strategy for improving cardiovascular risk factors, we have planned the High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP study). This study is a nonrandomized control trial in approximately 6500 participants in six intervention and six control companies. Our population strategy is based on three factors, nutrition, physical activity, and smoking. For each factor, a researchers working team was organized and has been supporting the intervention. A standardized method to obtain comparable data has also been established. In the baseline survey, urinary sodium excretion in male subjects was higher, and urinary potassium excretion was lower in both genders in the intervention group compared to the control group. The prevalence of hypertension for both genders was also higher in the intervention group. Male subjects in the intervention group had higher serum total cholesterol than controls, while high-density lipoprotein cholesterol was lower in both genders in the intervention group compared to the control group. These differences were reflected by our finding that the predicted relative risk of coronary heart disease for male subjects was significantly higher in the intervention group (relative risk, RR: 1.17; 95% confidence interval, 95% CI.: 1.09, 1.25) and significantly lower in the control group (RR: 0.93; 95% CI.: 0.89, 0.98) compared to a model Japanese population. Similar results were observed in the female subjects. Taken together, these findings indicate that it is possible to compare trends of predicted relative risk for coronary heart disease between two groups.

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.

Self-reported speed of eating and 7-year risk of type 2 diabetes mellitus in middle-aged Japanese men

OBJECTIVE This cohort study investigated the association between eating speed and the incidence of type 2 diabetes in middle-aged Japanese men. MATERIALS/METHODS Participants were 2,050 male employees of a metal products factory in Japan. We measured self-reported categorical eating speed. The incidence of diabetes was determined in annual medical examinations over a 7-year period. The association between eating speed and the incidence of diabetes adjusted for multiple variables (age, family history of diabetes, smoking, alcohol drinking, habitual exercise, and presence of hypertension and hyperlipidemia) was evaluated using Cox proportional hazards models. RESULTS The prevalence of obesity (BMI≥25 kg/m(2)) across the categories of eating speed (slow, medium, and fast) was 14.6, 23.3, and 34.8%, respectively, and a faster eating speed was associated with a higher prevalence of obesity. During the study, 177 participants developed diabetes. Crude incidence rates (/1,000 person-years) across the three categories of eating speed were 9.9, 15.6, and 17.3, respectively. Multivariate-adjusted hazard ratios (95% CI) across the categories were 1.00 (reference), 1.68 (0.93-3.02), and 1.97 (1.10-3.55), respectively, and eating speed was associated with the risk of diabetes (p for trend=0.030). After further adjustment for BMI, a significant association was not observed. CONCLUSIONS Eating speed was associated with the incidence of diabetes. Since these associations were not significant after adjusting for BMI, eating speed may act via its effect on body weight. Eating speed is a controllable risk factor, and eating slowly could be an acceptable lifestyle intervention for the prevention of diabetes mellitus.