Associations between metabolic syndrome and mortality from cardiovascular disease in Japanese general population, findings on overweight and non-overweight individuals. Ibaraki Prefectural Health Study.

BACKGROUND: The impact of being overweight, as a component of the metabolic syndrome (MetS), for cardiovascular disease (CVD) mortality was investigated and compared with the predictive value of MetS by 2 different definitions. METHODS AND RESULTS: A 12-year prospective study of 30,774 Japanese men and 60,383 women aged 40-79 years was conducted. The multivariate hazard ratio (HR; 95% confidence interval) of total CVD mortality for overweight subjects with >or=2 additional risk factors with reference to subjects with 0 of 4 MetS components was 1.83 (1.41-2.38) for men and 1.90 (1.45-2.49) for women, and for non-overweight subjects with >or=2 additional risk factors 1.75 (1.38-2.24) and 1.97 (1.52-2.55), respectively. The proportion of excess CVD deaths in the latter group was 1.5-fold higher than that in the former group. Multivariate HRs of coronary heart disease and total CVD mortality for MetS by the modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute were 1.62 (1.31-2.00) and 1.23 (1.09-1.39), respectively, for men and 1.32 (1.05-1.65) and 1.12 (1.00-1.25), respectively, for women. The respective HRs for MetS by the International Diabetic Federation definition did not reach statistical significance, except for coronary heart disease in men. CONCLUSIONS: Non-overweight individuals with metabolic risk factors, as well as overweight individuals with such factors, should be targeted to reduce the CVD burden in the general population.

Long-term exposure to elevated blood pressure and mortality from cardiovascular disease in a Japanese population: the Ibaraki Prefectural Health Study.

High blood pressure (BP) has been well established as a leading risk factor for both cardiovascular disease and mortality in general. However, the effect of long-term exposure to elevated BP on mortality risks in Asian populations remains unclear. The purpose of this study was to investigate the effects of time-averaged BP levels over 5 years on subsequent cardiovascular disease mortalities in a Japanese population. A total of 46,484 adults (14,771 men and 31,713 women) aged 40-79 years, who had no history of stroke or heart disease and who underwent health checkups in Ibaraki prefecture, Japan, in 1993 and 1998 were followed up through 2005. Hazard ratios (HRs) for mortality were estimated using a Cox proportional hazard model. Multivariate HRs (95% confidence interval) associated with a 10 mm Hg increase in systolic BP were measured in 1993 and 1998, and their averages were 1.11 (1.05-1.16), 1.13 (1.07-1.18) and 1.17 (1.10-1.27), respectively. Multivariate HRs for a 10 mm Hg increase in time-averaged systolic BP were 1.12 (1.03-1.21) in men and 1.24 (1.13-1.35) in women. The subgroup analysis of antihypertensive use showed that multivariate HRs for time-averaged systolic BP were 1.20 (1.11-1.29) in sustained non-users and 1.17 (1.04-1.32) in sustained users. Similar results were also obtained for diastolic BP. In conclusion, long-term exposure to elevated BP substantially associates with excess risk for cardiovascular disease mortality among Japanese subjects, irrespective of antihypertensive medication use. Thus, appropriate management of BP is important in both users and non-users of antihypertensive medication.

Relationship between obesity and incident diabetes in middle-aged and older Japanese adults: the Ibaraki Prefectural Health Study.

OBJECTIVE: To investigate the age-specific relationship between body mass index (BMI) and risk of diabetes in a Japanese general population. PARTICIPANTS AND METHODS: A cohort of Japanese men (N=19,926) and women (N=41,489) (aged 40-79 years) who under went community-based health checkups in 1993 and were free of diabetes was followed up by annual examinations with measurement of blood glucose concentrations until the end of 2006. Incident diabetes mellitus was defined as a blood glucose concentration of 126 mg/dL or greater under fasting conditions, 200 mg/dL or greater under nonfasting conditions, or diabetic medication use at baseline. Hazard ratios (HRs) for diabetes according to BMI were estimated using a Cox proportional hazard model. The model was adjusted for possible confounding variables. RESULTS: A total of 4429 participants (7.2%) developed diabetes (2065 men and 2364 women) during a mean follow-up of 5.5 years. Compared with those with a BMI of less than 25.0, the multivariate HRs for diabetes among participants with a BMI of 30.0 or greater were 1.40 (95% confidence interval [CI], 0.89-2.20) for men aged 40 to 59 years and 1.26 (95% CI, 0.81-1.96) for men aged 60 to 79 years (P=.002 for interaction). The HRs were 2.50 (95% CI, 2.01-3.11) for women aged 40 to 59 years and 1.80 (95% CI, 1.41-2.30) for women aged 60 to 79 years (P=.04 for interaction). CONCLUSION: The effect of obesity on the risk of diabetes is greater for middle-aged than for older adults.