BACKGROUND: We have previously reported that the prevalence of coronary artery calcification (CAC) was substantially lower among Japanese than American men despite a less favorable profile of many traditional risk factors in Japanese men. To determine whether lipoprotein-associated phospholipase A2 (Lp-PLA2) levels are related to the difference in the prevalence of CAC between the two populations. METHODS: A total of 200 men aged 40-49 years were examined: 100 residents in Allegheny County, Pennsylvania, United States, and 100 residents in Kusatsu City, Shiga, Japan. Coronary calcium score (CCS) was evaluated by electron-beam tomography, Lp-PLA2 levels, nuclear magnetic resonance (NMR) lipoprotein subclasses, and other factors were assessed in 2001-2002. RESULTS: Lp-PLA2 levels were higher among American than Japanese men (Mean ± standard deviation 301.7 ± 82.6 versus 275.9 ± 104.7 ng/mL, respectively, p=0.06). Among all Japanese men and those with low density lipoprotein (LDL) cholesterol ≥130 mg/dL, there was an inverse association of the prevalence of CCS>0 with the tertile groups of Lp-PLA2 levels (p=0.08 and p=0.03, respectively). American men did not have any association between CCS>0 with the tertile groups of Lp-PLA2 (p=0.62). Although Lp-PLA2 among both populations correlated positively with LDL and total cholesterol, American and Japanese men had different correlations with NMR lipoprotein subclasses. Reported high odds ratio for CCS>0 among American compared to Japanese men was not reduced after adjusting for Lp-PLA2 levels. CONCLUSION: Lp-PLA2 may have different mechanisms of action among American and Japanese men. Lp-PLA2 levels can not explain the observed CAC differences between the two populations. J Epidemiol 2007; 17: 179-185.
BACKGROUND: In Taiwan, there were few population-based studies of WTP values related to DR screening among persons with type 2 diabetes. This community-based study was to explore the willingness- to-pay (WTP) values for screening for diabetic retinopathy (DR) associated with varying degrees of DR among persons with type 2 diabetes in Kinmen, Taiwan. METHODS: A total of 725 eligible community-dwelling adults diagnosed with type 2 diabetes received DR screening during 1999-2002 and then evaluated WTP values in 2003. Diagnosis of DR was performed by a panel of ophthalmologists using ophthalmoscopy and a 45-degree color retinal photographs to examine fundus after dilating pupils. WTP values were measured by discrete-choice method. RESULTS: The 406 adults with type 2 diabetes participating in the WTP survey had a 56% response rate. Of 406 subjects, 265 (65.3%) said they would be willing to pay for DR screening to reduce blindness. The overall mean WTP value was New Taiwan Dollars 468.9±327.7 (US dollars 14.3±10.0). Age was borderline significant (p=0.07) related to WTP values. Those with severe stage DR had higher WTP values for screening than subjects with mild stage. CONCLUSIONS: Degree of DR was the independent factor affecting WTP values in DR screening among community-dwelling adults with type 2 diabetes. J Epidemiol 2007; 17: 186-193.
BACKGROUND: There have been few systematic investigations into risk and protective factors for pneumonia related mortality for community residents. This study investigated these factors utilizing a large cohort study on Japanese community residents. METHODS: Subjects, 110,792 individuals (aged 40-79 years) enrolled in 1988-1990, were followed until death, or when they moved away from the surveyed communities, or the end of 2003. Pneumonia death was defined following 480-486 (International Classification of Diseases, 9th Revision) or J12-J18 (10th Revision). Age-adjusted and multivariate hazard ratios were calculated along with 95% confidence intervals using the Cox proportional hazards model. RESULTS: With 1,112,747 person-years of the study, a total of 1,246 persons died of pneumonia. We found history of blood transfusion (multivariate hazard ratio=2.0 [95% confidence interval: 1.7-2.4]) was a potent novel risk factor. Walking 0.5-1 hour/day (0.8 [0.6-1.0]), 1+ hour/day (0.7 [0.6-0.8]), and/or a history of pregnancy (0.6 [0.4-0.9]) were found to reduce pneumonia mortality. A large body mass index (BMI) (25+kg/m2) was a protective factor (0.7 [0.5-0.8]), while low BMI (<18) was confirmed as a risk one (2.1 [1.7-2.6]). Smoking was an important preventable risk factor (1.6 [1.3-1.9], population attributable risk proportion=14%), and its cessation reduced risk (0.7 [0.5-1.0]) to levels comparable to neversmokers (0.7 [0.5-1.0]). CONCLUSIONS: The risk and protective factors ascertained here for pneumonia mortality among community residents, history of blood transfusion, large BMI, and walking habits, warrant further study. Smoking cessation may effectively reduce pneumonia mortality. J Epidemiol 2007; 17: 194-202.
BACKGROUND: Metabolic syndrome is known to increase morbidity and mortality of cardiovascular disease. The National Cholesterol Education Program Adult Treatment Expert Panel III in 2001 (revised in 2005) and the Japanese definition of metabolic syndrome were launched in 2005. No study regarding the association between metabolic syndrome by Japanese definition and mortality has been performed. The aim of this study was to clarify the prevalence of metabolic syndrome and its effects to mortality in a population-based cohort study. METHODS: A total of 2176 subjects who satisfied the necessary criteria for metabolic syndrome were examined between 1992 and 1995 as a part of Jichi Medical School Cohort Study by Japanese definition. Cox's proportional hazard models were used to analyze the association of metabolic syndrome with mortality. RESULTS: The prevalence of metabolic syndrome was 9.0% in males and 1.7% in females. There were 17 deaths (14 males), including 6 cardiovascular deaths (5 males), during a 12.5-year follow-up period among metabolic syndrome subjects. After adjusting for age, smoking status, and alcohol drinking status, the hazard ratio (95% confidence interval) for all-cause mortality was 1.13 (0.64-1.98) in males and 1.31 (0.41-4.18) in females, and HR for cardiovascular mortality was 1.84 (0.68-4.96) in males, and 1.31 (0.17-9.96) in females. CONCLUSION: No statistical significant relationship between metabolic syndrome by Japanese definition and all-cause mortality was observed in a population-based cohort study. J Epidemiol 2007; 17: 203-209.
BACKGROUND: In Asia there are few reports considering time intervals in the examination of clinical features of primary biliary cirrhosis (PBC). Therefore, we tried to compare the characteristics of patients with PBC in two different years. METHODS: In two fiscal years (1999 and 2004), 9,761 and 13,142 patients with symptomatic PBC were registered to receive public financial aid from the Ministry of Health, Labour and Welfare of Japan, respectively. For the present study, clinical data from 2,127 patients in 1999 and 6,423 ones in 2004 were available. We compared the data in the two different years, including sex, age, major symptoms, and laboratory data. RESULTS: Male/female ratios were the same figure (0.13 for 1999 and 2004). The median age was significantly older in 2004 than in 1999 (59 years for 1999, 63 years for 2004, respectively, p<0.01). Jaundice and esophageal varices were found significantly less frequent in 2004 than in 1999 (p<0.01 for each item). Levels of total bilirubin,γ-glutamyl transpeptidase (γ-GTP), total cholesterol, and immunoglobulin M were significantly lower in 2004 than in 1999 (p< 0.02 for total bilirubin, and p<0.01 for other each item). The positive rate of antimitochondrial antibodies was significantly higher in 1999 than in 2004 (87.0% for 1999, 83.5% for 2004, respectively, p<0.01)). Complicated autoimmune diseases such as Sjögren's syndrome, rheumatoid arthritis, and chronic thyroiditis were found significantly more frequent in 2004 than in 1999 (p<0.01 for each item). CONCLUSIONS: Among the patients with PBC in 2004, an increase in median age, and lower levels of laboratory data such asγ-GTP have been found compared to 1999. These results may show an accumulation of patients with better prognosis and the recent medical progress in controlling patients with PBC. J Epidemiol 2007; 17: 210-214.