Prognosis and prognostic factors in patients with idiopathic dilated cardiomyopathy in Japan.

BACKGROUND: There have been few large-scale nationwide studies investigating both the prognosis and the prognostic factors of idiopathic dilated cardiomyopathy (IDC). A predictive score that can be used in clinical practice has not been established. METHODS AND RESULTS: A nationwide epidemiological study of the prognosis of IDC was conducted in 1999 among randomly selected hospitals in Japan, and 147 departments participated in the present 5-year follow-up survey. The vital status of 1,554 IDC patients was collected in 2004 using medical records and residence-based registers. The crude 5-year survival rate for those diagnosed in 1998 was 78.6%. Cox's regression model selected 5 independent predictors of mortality: male sex, higher age, higher New York Heart Association functional class, higher left ventricular diameter index, and lower left ventricular ejection fraction. A predictive score using these 5 variables effectively predicted prognosis; 5-year survival rates were 90.6% in patients with a score of 4 or less and 49.0% in patients with a score of 9 or 10. CONCLUSIONS: This nationwide survey revealed the present prognostic status of IDC in Japan and 5 independent predictors of prognosis that can be used in clinical practice as a predictive score.

Effect of shift work on body mass index and metabolic parameters.

OBJECTIVES: The aim of this cohort study was to investigate the effects of shift work on changes in parameters related to metabolic disturbances. METHODS: The study population included 1529 male blue-collar workers, aged 19-49 years at baseline, working in a sash and zipper factory in Japan. The participants were divided into four groups according to the work schedule at baseline, the end point being workers doing fixed daytime work in both years (day-day), workers who changed from shift work to fixed daytime work (shift-day), workers who changed from fixed daytime work to shift work (day-shift), and workers doing shift work in both years (shift-shift). The changes in body mass index (BMI), blood pressure, serum cholesterol, and glycosylated hemoglobin A1c over a period of 10 years were compared among the groups by work schedule. RESULTS: The age-adjusted mean increase in BMI was 1.03 kg/m(2) for the day-shift workers, and it was significantly larger than that of the day-day workers and shift-day workers. The shift-shift workers showed a significantly larger increase in BMI than the day-day workers. These tendencies remained after adjustment for age and all other confounding factors, such as BMI, smoking, drinking, and leisure-time physical activity at baseline. The increase in total cholesterol tended to be higher among the shift-shift workers and the day-shift workers, but there were no significant differences. Blood pressure and hemoglobin A1c did not differ among the four groups. CONCLUSIONS: Shift work is considered to be a risk factor for excess weight. However, no significant difference in the biomarkers was found between daytime workers and shift workers.

Prognosis and prognostic factors in patients with hypertrophic cardiomyopathy in Japan: results from a nationwide study.

OBJECTIVE: To investigate prognosis and prognostic factors in patients with hypertrophic cardiomyopathy (HCM) in Japan. DESIGN: A nationwide epidemiological study. SETTING: Hospitals selected randomly from among all hospitals in Japan. PATIENTS: Clinical and epidemiological information for 2155 patients with HCM were collected in 1999. MAIN OUTCOME MEASURES: Patients were classified on the basis of baseline prognostic factors. Survival rates up to 5 years were calculated by Cox's proportional hazard model for 1605 patients. RESULTS: During the follow-up period, 241 deaths were recorded. The crude 5-year survival rate for the entire cohort was 86% (95% CI 84 to 88), and annual mortality ranged from 2.2% to 3.0%. A higher cardiothoracic ratio on chest x ray (HR 1.61; 95% CI 1.26 to 2.05, with 1 SD (6.2%) increase), a lower left ventricular ejection fraction (HR 1.42; 95% CI 1.20 to 1.69, with 1 SD (13%) decrease) and the presence of left bundle branch block (HR 3.14; 95% CI 1.28 to 7.71) were independently associated with a poorer prognosis, whereas the presence of apical hypertrophy at baseline (HR 0.58; 95%CI 0.36 to 0.92) predicted a better chance of survival. CONCLUSIONS: The nationwide survey of patients with hypertrophic cardiomyopathy yielded important information on its prognosis and prognostic factors. These observations afford, for the first time, a measure of risk stratification in patients with HCM in Japan.

Shift work and the risk of diabetes mellitus among Japanese male factory workers.

OBJECTIVES: This study investigated whether shift work is a risk factor for the development of diabetes mellitus. METHODS: The workers, 2860 men in a sash and zipper factory in the Toyama prefecture of Japan, were followed for 8 years, and the incidence rate of diabetes mellitus was determined. The cohort contained fixed daytime blue-collar workers, shift blue-collar workers, and white-collar workers. The workers were considered to have diabetes mellitus if, in their annual health examination, they had a glycated hemoglobin level of > or = 6.1 or if the diagnosis had been made by a hospital physician. The relative risks were estimated by Cox's proportional hazards regression model. RESULTS: Among the 2860 workers, there were 87 cases of new-onset diabetes mellitus, resulting in an incidence rate of 4.41 per 1000 person-years. The age-adjusted incidence was highest for the two-shift workers and lowest for the white-collar workers. The relative risk of diabetes mellitus for the two-shift workers and the three-shift workers compared with the fixed daytime workers was 1.73 and 1.33, respectively, after adjustment for all the confounding factors, but these values were not statistically significant. When the white-collar workers were used as a reference group, a significantly increased risk of diabetes mellitus was found for the two-shift workers (relative risk was 2.01 after adjustment for all confounding factors), but not for the three-shift workers or the fixed daytime blue-collar workers. CONCLUSIONS: The study suggests that shift work is a risk factor for the onset of diabetes mellitus and that there is a different risk associated with different shift schedules.

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 > or = 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 > or = 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 > or = 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 > or = 300 g/week was associated with significantly greater annual BP increase, and baseline BP was significantly higher in drinkers consuming > or = 200 g/week. It is necessary to limit alcohol intake to less than 200 g/week to prevent hypertension.

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 chi2 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.

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 approximately 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 (>or=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.