Chi-Yu Yang

Chin-Shan Community Cardiovascular Cohort in Taiwan–baseline data and five-year follow-up morbidity and mortality

A cohort consisting of 3602 residents (82.8% of the target population) aged 35 years and older was established in 1990 in the Chin-Shan Community, a suburb 20 miles outside of metropolitan Taipei, Taiwan. The long-term objective was to investigate the prospective impact on cardiovascular health in a society undergoing transition from a developing to a developed nation. This article presents the study design, selected baseline risk factors of cardiovascular diseases (CVD), and CVD events at the 5-year follow-up evaluation with an emphasis on sociodemographic differences. The multivariate logistic regression analyses revealed that white-collar individuals were more likely than blue-collar workers to have dyslipidemia including high-density lipoprotein cholesterol (HDL-C) levels <35 mg/dl [odds ratio (OR) = 1.7, 95% confidence interval (CI) = 1.2-2.4] and low-density lipoprotein cholesterol (LDL-C) levels >/=160 mg/dl (OR = 1.3, 95% CI = 1.0-1.7). However, they were at slightly lower risk for stroke and CVD/sudden death, and at moderately higher risk for coronary artery disease and diabetes, although both these trends were not significant. Men were more likely than women to have HDL-C levels <35 mg/dl (OR = 1.8, 95% CI = 1.4-2.2), but they were less likely to have LDL-C levels >/=160 mg/dl (OR = 0.7, 95% CI = 0.6-0.8). The risk of CVD/sudden death was higher for men than for women during the follow-up period (OR = 1.9, 95% CI = 1.3-2.9). This could be due to risk factors such as a much higher prevalence of tobacco (61.9% vs. 4.5%) and alcohol (43.7% vs. 6.4%) use in men. In conclusion, individuals of higher socioeconomic status have a higher prevalence of dyslipidemia but slightly lower 5-year incidence of CVD events.

Peripheral differential leukocyte counts in humans vary with hyperlipidemia, smoking, and body mass index

Reports of diverse relationships between blood concentrations of different lipids and peripheral total leukocyte count, and a unique lower peripheral monocyte count in hypercholesterolemia, have driven us to think that in humans, peripheral differential leukocyte counts may be influenced differently by different types of hyperlipidemia. Our subjects were Taipei residents who attended a regular health check program in our hospital in 1998. A total of 3,282 subjects was enrolled, including 1,677 normolipidemic, 960 untreated borderline hyperlipidemic, and 645 untreated hyperlipidemic subjects. By one-way analysis of variance (ANOVA), we found that different types of hyperlipidemia were associated with significant differences in differential leukocyte counts. In hypertriglyceridemia, the total leukocyte count and counts of all leukocyte subtypes were significantly higher than those in normolipidemia. Pure hypercholesterolemia, by contrast, was associated with a significantly lower monocyte count and no significant difference in other leukocyte counts. By two-way ANOVA adjusted for presence and degree of hyperlipidemia, we found significantly higher counts of total leukocytes and of all leukocyte subtypes in smokers, and significantly positive trends in relationships between body mass index (BMI) and counts of all leukocytes, neutrophils, lymphocytes, and monocytes. By multivariate regression analysis including all subjects, the serum triglyceride (TG) level was positively correlated with total leukocyte count and counts of all subtypes except eosinophils. On the contrary, serum high density lipoprotein-cholesterol had a negative correlation with total leukocyte count and with counts of neutrophils, monocytes, and basophils. In these multivariate regression analyses, there was no significant correlation between lipid levels and eosinophil count, whereas smoking was consistently associated with significantly higher counts of all leukocyte subtypes, including eosinophils. BMI had a significantly positive correlation with counts of all leukocytes, neutrophils, lymphocytes, and monocytes.

In Hypercholesterolemia, Lower Peripheral Monocyte Count Is Unique Among the Major Predictors of Atherosclerosis

Many studies have shown that enhanced monocyte adherence is an important factor in the initiation of atherosclerosis. Because the relationships between circulating monocyte count and atherosclerosis or its major predictors have received little attention, we conducted this study with the aim of clarifying these relationships. The study included 409 men and women who underwent a carotid artery duplex study and white blood cell analysis (Sysmex Cell Counter) during a 2-day health check at our hospital in 1994. We found no correlation between preexisting carotid atherosclerosis and monocyte count. After adjustment for age and sex, hypercholesterolemia, among the major predictors of atherosclerosis, showed a unique correlation with both lower monocyte count and percentage (P < .001, P < .0001, respectively), whereas smoking was correlated with a higher monocyte count (P < .001). There was a slight but nonsignificant increase in monocyte count in hypertension, diabetes, and hypertriglyceridemia. Our results imply that: (1) hypercholesterolemia has a strong, peripheral monocyte-reducing effect, probably due to direct enhancement of monocyte adhesion to the endothelium, which subsequently initiates the atherosclerotic process, and (2) the mechanisms of other predictor(s)-induced atherosclerosis may be quite different from that of hypercholesterolemia. Another possible explanation for the inverse correlation between monocyte count and serum cholesterol level is that decreased monocyte levels might lead to hypercholesterolemia because of decreased uptake of cholesterol from the plasma by less monocyte-derived macrophages. The reasons why preexisting carotid atherosclerosis did not correlate with monocyte count are also discussed.

Consistency of genetic inheritance mode and heritability patterns of triglyceride vs. high density lipoprotein cholesterol ratio in two Taiwanese family samples.

BackgroundTriglyceride/HDL cholesterol ratio (TG/HDL-C) is considered as a risk factor for cardiovascular events. Genetic components were important in controlling the variation in western countries. But the mode of inheritance and family aggregation patterns were still unknown among Asian-Pacific countries. This study, based on families recruited from community and hospital, is aimed to investigate the mode of inheritance, heritability and shared environmental factors in controlling TG/HDL-C.ResultsTwo populations, one from community-based families (n = 988, 894 parent-offspring and 453 sibling pairs) and the other from hospital-based families (n = 1313, 76 parent-offspring and 52 sibling pairs) were sampled. The population in hospital-based families had higher mean age values than community-based families (54.7 vs. 34.0). Logarithmic transformed TG/ HDL-C values, after adjusted by age, gender and body mass index, were for genetic analyses. Significant parent-offspring and sibling correlations were also found in both samples. The parent-offspring correlation coefficient was higher in the hospital-based families than in the community-based families. Genetic heritability was higher in community-based families (0.338 ± 0.114, p = 0.002), but the common shared environmental factor was higher in hospital-based families (0.203 ± 0.042, p < 0.001). Commingling analyses showed that more than one-component distribution models were the best-fit models to explain the variance in both populations. Complex segregation analysis by regressive models revealed that in both samples the best-fit model of TG/HDL-C was the model of environmental effects plus familial correlation, in which significant parent-offspring and sibling correlations were demonstrated. Models of major gene effects were rejected in both samples.ConclusionVariations of TG/HDL-C in the normal ranges were likely to be influenced by multiple factors, including environmental and genetic components. Higher genetic factors were proved in younger community-based families than in older hospital-based families.

Peripheral differential leukocyte counts and subsequent mortality from all diseases, cancers, and cardiovascular diseases in Taiwanese

BACKGROUND AND PURPOSE A higher total leukocyte count has been reported to predict all-cause mortality in men, but data are limited for this relation in women and for the relation between differential leukocyte counts and all-cause mortality in both men and women. This study was designed to analyze these relationships in Taiwanese. METHODS A total of 8447 subjects were enrolled from participants in a physical check-up program at National Taiwan University Hospital from 1995 to 1997. Information on mortality was obtained from a national mortality databank that was updated to the end of 2001. Data were analyzed by Students t test and Cox regression analysis. RESULTS Among the 245 deaths, 88 were due to cancer and 62 were due to cardiovascular diseases. Cox regression analysis revealed an inverse association between lymphocyte count and all-cause mortality in the study group as a whole (all subjects, p < 0.01, hazard ratio = 0.73). This inverse association was mainly due to an inverse association between lymphocyte count and cancer mortality (p < 0.05, hazard ratio = 0.64), especially the mortality from hepatoma (p = 0.010, hazard ratio = 0.29). The latter hazard ratio of 0.29 indicates that, in all subjects, every decrease of 1.0 x 10(9)/L in lymphocyte count increased the risk of mortality from hepatoma by 3.45-fold during an average follow-up period of 65.5 months. There was a positive association between total leukocyte count and all-cause mortality in men (p < 0.05, hazard ratio = 1.10), mainly due to both the neutrophil and monocyte counts having positive associations with the cardiovascular mortality (both p < 0.05, hazard ratio = 1.23 and 1.22, respectively). The latter hazard ratio of 1.22 indicates that, in men, every increase of 0.1 x 10(9)/L in monocyte count increased the risk of cardiovascular mortality by 1.22-fold. CONCLUSIONS In Taiwanese adults of both genders, a lower lymphocyte count is associated with cancer mortality, especially mortality from hepatoma. In Taiwanese men, higher neutrophil and monocyte counts are associated with cardiovascular mortality.

Impact of an audit program and other factors on door-to-balloon times in acute ST-elevation myocardial infarction patients destined for primary coronary intervention.

OBJECTIVES This before-after study investigated the association between an audit program and door-to-balloon times in patients with acute ST-elevation myocardial infarction (STEMI) and explored other factors associated with the door-to-balloon time. METHODS An audit program that collected time data for essential time intervals in acute STEMI was developed with data feedback to both the Department of Emergency Medicine and the Department of Cardiology. The door-to-balloon times for 76 consecutive acute STEMI patients were collected from February 16, 2007, through October 31, 2007, after the implementation of the audit program, as the intervention group. The control group was defined by 104 consecutive acute STEMI patients presenting from April 1, 2006, through February 15, 2007, before the audit was applied. A multivariate linear regression model was used for analysis of factors associated with the door-to-balloon time. RESULTS The geometric mean 95% CI of the door-to-balloon time decreased from 164.9 (150.3, 180.9) minutes to 141.9 (127.4, 158.2) minutes (p = 0.039) in the intervention phase. The median door-to-balloon time was 147.5 minutes in the control group and 136.0 minutes in the intervention group (p = 0.09). In the multivariate regression model, the audit program was associated with a shortening of the door-to-balloon time by 35.5 minutes (160.4 minutes vs. 195.9 minutes, p = 0.004); female gender was associated with a mean delay of 58.4 minutes (208.9 minutes vs. 150.5 minutes; p = 0.001); posterolateral wall infarction was associated with a mean delay of 70.5 minutes compared to anterior wall infarction (215.4 minutes vs. 144.9 minutes; p = 0.037) and a mean delay of 69.5 minutes compared to inferior wall infarction (215.4 minutes vs. 145.9 minutes; p = 0.044). The use of a glycoprotein IIb/IIIa inhibitor was associated with a 46.1 minutes mean shortening of door-to-balloon time (155.7 minutes vs. 201.8 minutes; p < 0.001). CONCLUSIONS The implementation of an audit program was associated with a significant reduction in door-to-balloon times among patients with acute STEMI. In addition, female patients, posterolateral wall infarction territory, and nonuse of glycoprotein IIb/IIIa inhibitor were associated with longer door-to-balloon times.

A double-blind comparison of once-daily metoprolol controlled-release and atenolol in the treatment of Chinese patients with mild to moderate hypertension

SummaryThe efficacy and tolerability of controlled-release metoprolol (metoprolol CR/ZOK), 100–200 mg, and atenolol, 50–100 mg, once daily was compared in Chinese patients with mild to moderate essential hypertension. The study was of a randomized, double-blind, two-way crossover design. The active treatment periods lasted 4 weeks each and were preceded by a 4-week placebo run-in period. The two double-blind phases were separated by a 2-week washout period on placebo. Blood pressures and heart rates were measured at rest in each 2-week visit and during exercise at the end of each treatment period. Twenty-four patients (M/F=14/10) were valid for efficacy analysis. Their ages ranged from 39 to 68, with a mean of 53.5 years. The rest supine blood pressure and heart rate before active treatment was 160±15/106±6 mmHg and 75±14 beats/min (mean±SD), respectively. A responder was defined as exhibiting a supine diastolic blood pressure ≤90 mmHg or a supine diastolic blood pressure reduction of at least 10% of the baseline level. Both agents had high response rate: 88% and 92% of all patients responded to metoprolol CR/ZOK and atenolol, respectively. Both active treatments considerably reduced resting systolic and diastolic blood pressures and heart rates as compared with baseline (p<0.001), respectively. With controlled-release metoprolol, a more pronounced β1 blockade was obtained than with atenolol, which was expressed as a significant reduction in exercise-induced heart rate at the highest comparable workload compared with placebo (p<0.05). These findings are compatible with those reported from western populations.

Detection of Asymptomatic Paroxysmal Atrial Fibrillation with the Trans-Telephonic Electrocardiograph System

Paroxysmal atrial fibrillation (PAF) carries an equally high annual stroke rate as chronic atrial fibrillation (AF). Furthermore, the frequency and duration of PAF are thought to be associated with stroke risk. In this pilot study, a trans-telephonic electrocardiograph (TTE) monitoring system was used to detect asymptomatic PAF and to study the relationship between ischemic stroke and the frequency of PAF. Between December 2004 and April 2006, 70 patients enrolled in the TTE monitoring program. Patients either transmitted electrocardiograms (ECGs) daily or upon experiencing cardiac symptoms. Of the 70 patients included, 25 were diagnosed with PAF. In total, 11% (855/7,768) of the recordings were diagnosed as PAF, yet less than 2% of total calls collected and less than 17% of all the calls with PAF were associated with obvious symptoms. Four patients developed five ischemic strokes resulting in a calculated annual stroke rate of 0.56%. Patients with stroke had more episodes of AF (56.5±106.3 versus 6.7±85.9, p=0.685) and symptomatic AF episodes (9.8±17.5 versus 4.9±8.1, p=0.381) than the patients who did not have a stroke, but the differences were not statistically significant because of the low numbers of patients and episodes. Most PAF episodes were asymptomatic, and the TTE system could easily detect these episodes. Furthermore, these four patients tended to have more episodes of PAF and more symptomatic attacks of PAF than patients who did not have a stroke.