Major gene effects in systolic and diastolic blood pressure in families receiving a health examination in Taiwan

Common sequence variants in CD36 gene and the levels of triglyceride and high-density lipoprotein cholesterol among ethnic Chinese in Taiwan

Background

Evidence of the genetic association between CD36 candidate gene and the risk of metabolic syndrome and its components has been inconsistent. This case–control study assessed the haplotype-tagged SNPs from CD36 on the risk of metabolic syndrome and components.

Methods and results

We recruited 1,000 cases and age, gender-matched controls were randomly selected from the participants with metabolic syndrome defined by International Diabetes Federation. Overall, the haplotype tagged SNPs of CD36 gene were not related to the risk of metabolic syndrome. For individuals with normal lipid levels, several SNPs were significantly associated with the triglycerides and HDL-cholesterol levels: Subjects with rs3211848 homozygote had a higher triglyceride level (99.16 ± 2.61 mg/dL), compared with non-carriers (89.27 ± 1.45 mg/dL, P = 0.001). In addition, compared with non-carriers, individuals with rs1054516 heterozygous and homozygous genotypes had a significantly lower HDL-cholesterol (46.6 ± 0.46 mg/dL for non-carrier, 44.6 ± 0.36 mg/dL for heterozygous, and 44.3 ± 0.56 mg/dL for homozygous, P = 0.0008).

Conclusion

The CD36 gene variants were significantly associated with triglycerides and HDL-cholesterol concentrations among ethnic Chinese in Taiwan.

Prediction model for high glycated hemoglobin concentration among ethnic Chinese in Taiwan

Background

This study aimed to construct a prediction model to identify subjects with high glycated hemoglobin (HbA1c) levels by incorporating anthropometric, lifestyle, clinical, and biochemical information in a large cross-sectional ethnic Chinese population in Taiwan from a health checkup center.

Methods

The prediction model was derived from multivariate logistic regression, and we evaluated the performance of the model in identifying the cases with high HbA1c levels (> = 7.0%). In total 17,773 participants (age > = 30 years) were recruited and 323 participants (1.8%) had high HbA1c levels. The study population was divided randomly into two parts, with 80% as the derivation data and 20% as the validation data.

Results

The point-based clinical model, including age (maximal 8 points), sex (1 point), family history (3 points), body mass index (2 points), waist circumference (4 points), and systolic blood pressure (3 points) reached an area under the receiver operating characteristic curve (AUC) of 0.723 (95% confidence interval, 0.677- 0.769) in the validation data. Adding biochemical measures such as triglycerides and HDL cholesterol improved the prediction power (AUC, 0.770 [0.723 - 0.817], P = < 0.001 compared with the clinical model). A cutoff point of 7 had a sensitivity of 0.76 to 0.96 and a specificity of 0.39 to 0.63 for the prediction model.

Conclusions

A prediction model was constructed for the prevalent risk of high HbA1c, which could be useful in identifying high risk subjects for diabetes among ethnic Chinese in Taiwan.

AGT genetic variation, plasma AGT, and blood pressure: An analysis of the Utah Genetic Reference Project pedigrees

BACKGROUND

Much remains unknown about the genetic factors that contribute to essential hypertension. The Utah Genetic Reference Project (UGRP) large pedigree collection provides new opportunities to study quantitative relationships between genetic variation, endophenotypes, and blood pressure.

METHODS

We analyzed the relationship between common single-nucleotide polymorphisms (SNPs) and haplotypes spanning the angiotensinogen (AGT) gene and promoter region, plasma AGT levels, and systolic (SBP) and diastolic blood pressure (DBP) in 424 individuals from 41 two-generation UGRP families.

RESULTS

Plasma AGT levels are significantly correlated among UGRP family members. Correlations are higher for males than for females. Parent-offspring correlations for plasma AGT (0.30) are higher than those for SBP (0.26) and DBP (0.17) (all P values <0.01). The additive heritability (h(2)) for plasma AGT is high (0.74) and substantially exceeds heritability estimates for SBP (0.26) and DBP (0.16) (all P values <0.01). Significant linkage (logarithm of the odds (LOD) >3) is found between six AGT SNPs and plasma AGT. A model that utilizes three AGT haplotype groups produces the best LOD score (5.1) that exceeds the best single SNP LOD score (3.8). Plasma AGT and blood pressure were not significantly correlated.

CONCLUSIONS

Plasma AGT levels demonstrate high heritability in 41 UGRP families. Locus-specific heritability estimates for AGT SNPs and haplotypes approach 67%, indicating that variation at AGT accounts for a large percentage of the heritability of plasma AGT. A three-way haplotype model outperforms single SNPs for quantitative linkage analysis to plasma AGT. In these predominantly normotensive individuals, plasma AGT did not correlate significantly with blood pressure.

High-density lipoprotein-cholesterol trajectory pattern, associated lifestyle and biochemical factors among Taiwanese

BACKGROUND

Little is known about high-density lipoprotein-cholesterol (HDL-C) trajectory patterns among ethnic Chinese in Taiwan, or the effects of lifestyle and biochemical measurements on these trajectory patterns.

METHODS AND RESULTS

This longitudinal study was based on 330 adult participants who underwent biochemical measurements annually from 2003 to 2006. As time progressed, HDL-C increased significantly; women had a consistently higher value (10 mg/dl) than men. An increase of 1 kg/m(2) in body mass index was associated with -1.00 +/-0.25 mg/dl HDL-C for women (P=0.0001) and -0.78 +/-0.11 mg/dl for men (P<0.0001). Current smoking was inversely associated with HDL-C in men only. Systolic blood pressure and exercise frequency were positively associated with HDL-C in men only. Compared with non-smokers, participants who smoked had a lower HDL-C level of -8.42 +/-4.90 mg/dl in women (P=0.09) and -3.60 +/-0.94 mg/dl in men (P=0.0001). In contrast, a 1-h increase in exercise frequency every week was related to an increased HDL-C level of 0.38 +/-0.28 mg/dl for women (P=0.18) and 0.53 +/-0.14 mg/dl for men (P=0.0001).

CONCLUSIONS

An increase in HDL-C was shown over a 4-year period and gender-specific lifestyle factors were associated with HDL-C concentration among ethnic Chinese in Taiwan.

Urinary sodium and potassium excretion and risk of hypertension in Chinese: report from a community-based cohort study in Taiwan

BACKGROUND

Dietary sodium intake is associated with blood pressure and hypertension risk. However, most of the studies have been conducted in whites and it is not clear whether the effects exist in Asian populations.

OBJECTIVE

The purpose of the present study was to investigate the role of 24-h urinary sodium excretion and hypertension risk among ethnic Chinese.

DESIGN

A prospective cohort design on community.

SETTING AND PARTICIPANTS

One thousand five hundred and twenty middle-aged and elderly participants who were free from hypertension at baseline and had available urine electrolyte data.

MAIN OUTCOME MEASURES

Hypertension incidence.

RESULTS

During a median 7.93 years of follow-up (interquartile range = 4.07-9.04 years), we documented 669 cases of incident hypertension. The multivariate risk was 1.26 (95% confidence interval = 1.01-1.57; P = 0.043) for individuals in the highest quartile of urinary sodium excretion as compared with those in the second quartile. A significant J-shape relationship between urinary sodium excretion and the risk of hypertension was observed, with the test for linear relation being rejected (P = 0.046). Participants who were in the highest quartile of urinary sodium excretion and higher baseline blood pressure had a 2.43-fold increased risk of hypertension (95% confidence interval = 1.72-3.22) compared with those in the lowest quartiles of urinary sodium and lower blood pressure.

CONCLUSION

Urinary sodium excretion was associated with the risk of hypertension among ethnic Chinese. Urinary sodium excretion, as a marker of dietary sodium intake, can be useful for a comprehensive evaluation of hypertension risk in Asian populations.

Renal function and metabolic syndrome components on cardiovascular and all-cause mortality

OBJECTIVES

Impaired renal function and metabolic syndrome have been associated with risk of cardiovascular disease (CVD). We investigated their roles in CVD and all-cause death among ethnic Chinese population.

METHODS

We followed up a cohort of 11429 men and 7472 women aged 20 years and older for an average 4.9 years (median: 3.5, inter-quartile range: 2.7-7.9) from the tertiary hospital health check-up population.

RESULTS

CVD death rates increased when the quintiles of each variable progressed. Metabolic syndrome was a significant predictor for CVD death, with relative risk of up to 4.68. In the multivariate adjusted model that included metabolic syndrome, quintiles of serum creatinine concentrations, estimated glomerular filtration rate (GFR), and uric acids were significantly associated CVD death, with the highest relative risk of creatinine concentration (11.22, 95% confidence interval [CI]: 2.43-51.7, P for trend: <0.001). Serum creatinine concentrations and estimated GFR had the higher areas under ROC curves of CVD death (0.76, 95% CI: 0.71-0.80 for creatinine and 0.76, 95% CI: 0.72-0.81 for estimated GFR). The two marker models showed that metabolic syndrome and impaired renal function had the most significant roles in predicting CVD deaths; the multivariate relative risk was 30.6 (95% CI: 3.7-254, P: 0.002) in participants with the highest creatinine and presence of metabolic syndrome compared with those with the lowest and absence of metabolic syndrome.

CONCLUSIONS

Impaired renal function and metabolic syndrome are important risk factors for CVD and all-cause deaths among ethnic Chinese.

Familial aggregation of metabolic syndrome among the Chinese: report from the Chin-Shan community family study

Genetic study on metabolic syndrome is a great challenge, due to its complex traits and the pleiotropic manifestation of atherosclerosis. Familial aggregation and recurrence risk ratio can provide the insight of possible genetic mechanism. The Chin-Shan community family study was based on adolescent probands and their relatives (1356 subjects) who were recruited from one junior high school in the community. Structured questionnaires and biochemical measures were obtained in standard procedures. Definition of metabolic syndrome was followed using the criteria defined by the third adult treatment panel, with a modification of the criteria for adolescent and Asian population. Grandmothers had the highest frequencies (70%) in metabolic syndrome and various atherosclerotic risks. Three factors were found and thus explained 68% of the overall variance. Estimated heritability was the highest in LDL and cholesterol factor (0.36 and 0.40), then blood pressure/obesity factor (0.27), and insulin resistance/dyslipidemia (0.27). Recurrence risk ratio among siblings was 2.95 (95% confidence interval [CI]: 1.39-6.26). The adjusted odds ratio (OR) of proband's metabolic syndrome status was 1.99 (95% CI: 1.08-3.66). The adjusted odds ratios for the three factors for predicting metabolic syndrome were all significant, with highest risk in blood pressure/obesity factor (OR: 1.27, CI: 1.22-1.33), then insulin resistance/dyslipidemia (OR: 1.29, CI: 1.16-1.23). This study demonstrated clearly familial aggregation and recurrence risk ratio of metabolic syndrome and components among the general ethnic Chinese population in Taiwan.

Prevalence, agreement and classification of various metabolic syndrome criteria among ethnic Chinese: a report on the hospital-based health diagnosis of the adult population

OBJECTIVES

Many criteria of metabolic syndrome have been made available to practitioners in the recent past. This study has been designed to investigate the distribution, agreement and classification patterns of these criteria among the ethnic Chinese population.

METHODS

A total of 6610 (women, 42.5%) adults (mean, 52.3 years) were recruited from the hospital-based health diagnosis program during 2004. We divided criteria of metabolic syndrome into two groups: those with a major component required (WHO, EGIR, AACE, IDF) and those with equal component (ATP III, AHA, with modifications).

RESULTS

The highest standardized rates were in Asian AHA criterion, up to 29.8% in men and 25.6% in women. The lowest rates were in WHO criterion, 8.8% in men and 8.0% in women. The kappa values using all criteria were 0.59 in men and 0.65 in women and decreased in the major component group (0.50 in men, 0.54 in women), while increased in the equal component group (0.83 in men, 0.81 in women). Using hierarchical cluster analysis and dendrograms, two large clusters were identified in men (major components and equal components); however, mixed sub-clusters of major and equal components apparently grouped by insulin resistance and obesity criteria in women.

CONCLUSIONS

There is substantial agreement and grouping of metabolic syndrome models among ethnic Chinese.

Major gene effects on apolipoprotein B concentrations in families of adolescents—Results from a community-based study in Taiwan

BACKGROUND

Apolipoprotein (Apo) B is considered as a risk factor for atherosclerosis. Previous reports of segregation analyses on the mode of inheritance of Apo B were inconsistent because of heterogeneity in study population or elderly adult diseased probands. We performed complex segregation analysis of Apo B levels in the families of adolescents, systematically ascertained from junior high school students in a rural community in Taiwan.

RESULTS

There is a sex-specific influence in the variation of apo B levels. The mother-daughter (0.216), sister-sister (0.181), sister-brother (0.179) correlations were higher than father-son (0.206), brother-brother (0.002) or cross-sex correlations for the variation in Apo B levels. By the variance component model, the heritability estimate was 26.3+/-6.7% (P<.0001) in Apo B levels. Commingling analysis indicated that a 2-component distribution was needed to account for Apo B variation. Segregation analysis using regressive models revealed that the best-fit model of Apo B was the model of major gene effect plus familial correlation. The gene frequency controlling high Apo B was 0.17, and 3 means of genotypes were 56.3, 54,2, and 117.2 mg/dl.

CONCLUSION

Variations of Apo B levels in the normal range among adolescent families are controlled by major gene, and further identification of this gene locus will be mandatory.