Ethnic differences in hepatic lipase and HDL in Japanese, black, and white Americans: role of central obesity and LIPC polymorphisms

Dyslipidaemia-Genotype Interactions with Nutrient Intake and Cerebro-Cardiovascular Disease

A comprehensive understanding of gene-diet interactions is necessary to establish proper dietary guidelines to prevent and manage cardio-cerebrovascular disease (CCD). We investigated the role of genetic variants associated with dyslipidaemia (DL) and their interactions with macro-nutrients for cardiovascular disease using a large-scale genome-wide association study of Korean adults. A total of 58,701 participants from a Korean genome and epidemiology study were included. Their dietary intake was assessed using a food frequency questionnaire. Dyslipidaemia was defined as total cholesterol (TCHL) ≥ 240 mg/dL, high-density lipoprotein (HDL) < 40 mg/dL, low-density lipoprotein (LDL) ≥ 160 mg/dL, triglycerides (TG) ≥ 200 mg/dL, or dyslipidaemia history. Their nutrient intake was classified as follows: protein intake: high ≥ 30%, 30% > moderate ≥ 20%, and 20% > low in daily total energy intake (TEI); carbohydrate intake: high ≥ 60%, 60% > moderate ≥ 50%, and 50% > low; fat intake: high ≥ 40%, 40% > moderate ≥ 30%, and 30% > low. Odds ratios and 95% confidence intervals were calculated after adjusting for age; sex; body mass index (BMI); exercise status; smoking status; alcohol intake; principal component 1 (PC1); principal component 2 (PC2); and intake of carbohydrates, fats, and proteins. This analysis included 20,596 patients with dyslipidaemia and 1027 CCD patients. We found that rs2070895 related to LIPC was associated with HDL-cholesterol. Patients with the minor allele (A) in rs2070895 had a lower risk of CCD than those carrying the reference allele (G) (odds ratio [OR] = 0.8956, p-value = 1.78 × 10−2). Furthermore, individuals consuming protein below 20% TEI with the LIPC reference allele had a higher risk of CCD than those with the minor allele (interaction p-value 6.12 × 10−3). Our findings suggest that the interactions of specific polymorphisms associated with dyslipidaemia and nutrients intake can influence CCD.

The HERITAGE Family Study: A Review of the Effects of Exercise Training on Cardiometabolic Health, with Insights into Molecular Transducers

The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implications for cardiometabolic health and cardiorespiratory fitness. It begins with overviews of background and planning, recruitment, testing and exercise program protocol, quality control measures, and other relevant organizational issues. A summary of findings is then provided on cardiorespiratory fitness, exercise hemodynamics, insulin and glucose metabolism, lipid and lipoprotein profiles, adiposity and abdominal visceral fat, blood levels of steroids and other hormones, markers of oxidative stress, skeletal muscle morphology and metabolic indicators, and resting metabolic rate. These summaries document the extent of the individual differences in response to a standardized and fully monitored endurance exercise program and document the importance of familial aggregation and heritability level for exercise response traits. Findings from genomic markers, muscle gene expression studies, and proteomic and metabolomics explorations are reviewed, along with lessons learned from a bioinformatics-driven analysis pipeline. The new opportunities being pursued in integrative -omics and physiology have extended considerably the expected life of HERITAGE and are being discussed in relation to the original conceptual model of the study.

The Association of Passive Smoking and Dyslipidemia Among Adolescence in Japan: Results From A-CHILD Study

CONTEXT

Passive smoking in childhood has been reported to be associated with dyslipidemia in Western countries. However, this association in Asian countries remains unclear. Further, no study has investigated the sex difference of the association.

OBJECTIVE

This study aimed to elucidate the association between passive smoking and dyslipidemia in adolescent boys and girls in Japan.

METHODS

We used a cross-sectional data of junior high school students in the Adachi Child Health Impact of Living Difficulty (A-CHILD) study in Adachi City, Tokyo, Japan in 2016 and 2018. Of the 1431 available students, 1166 students and their parents responded to the survey, including frequency of passive smoking (response rate 81.5%). We assessed dyslipidemia using total cholesterol (TC) levels, low-density lipoprotein cholesterol (LDL-C) levels and high-density lipoprotein cholesterol (HDL-C) levels. The association between passive smoking and dyslipidemia was evaluated by using multivariate regression analyses adjusted for socioeconomic status and lifestyle factors stratified by boys (N = 564) and girls (N = 602).

RESULTS

Among boys, HDL-C levels were significantly lower if exposed to passive smoking frequently, compared with those not exposed (β = -3.19; 95% CI, -5.84 to -0.55). However, this trend does not hold true among girls. Passive smoking was not associated with TC levels and LDL-C levels in either boys or girls.

CONCLUSION

We found that exposure to passive smoking was associated with HDL-C level among boys in Japan, but not in girls. Further longitudinal study is needed to confirm the association between passive smoking and dyslipidemia among boys in Japan.

The Effect of Haplotypes in the CETP and LIPC Genes on the Triglycerides to HDL-C Ratio and Its Components in the Roma and Hungarian General Populations

BACKGROUND

The triglycerides (TG) to high-density lipoprotein (HDL)-cholesterol (HDL-C) ratio (TG/HDL-C) is a well-known predictor for cardiovascular diseases (CVDs) with great heritability background. The cholesteryl ester transfer protein (CETP) and hepatic lipase (LIPC) gene affect TG/HDL-C ratio. This study aims to explore the association between haplotypes (H) in CETP (based on 5 single nucleotide polymorphisms (SNPs)) and LIPC (based on 6 SNPs) genes and the TG/HDL-C ratio and its components, among Roma and Hungarian general populations.

METHODS

The prevalence of haplotypes and their effect on HDL-C, TG and TG/HDL-C ratio were calculated in both populations and compared.

RESULTS

Ten haplotypes in CETP and 6 in LIPC gene were identified. Three haplotypes in CETP and 3 in LIPC have significant effect on HDL-C level, whereas two in CETP and 3 in LIPC on TG level. The H6 in CETP (β = 0.52, p = 0.015; odds ratio (OR) = 1.87, p = 0.009) and H5 in LIPC (β = 0.56, p < 0.001; OR = 1.51, p = 0.002) have a significant increasing effect on TG/HDL-C ratio and have shown higher prevalence among the Roma, as compared to Hungarian general population. The H2 in the CETP gene has a decreasing effect on the TG/HDL-C ratio (OR = 0.58, p = 0.019) and is significantly less frequent among the Roma.

CONCLUSIONS

Accumulation of harmful haplotypes in CETP and LIPC genes might have a role in the elevated TG/HDL-C ratio in the Roma population, which contributes to a higher risk in the development of cardiovascular diseases.

Ten years in: APOL1 reaches beyond the kidney

PURPOSE OF REVIEW

APOL1 nephropathy risk variants drive most of the excess risk of chronic kidney disease (CKD) seen in African Americans, but whether the same risk variants account for excess cardiovascular risk remains unclear. This mini-review highlights the controversies in the APOL1 cardiovascular field.

RECENT FINDINGS

In the past 10 years, our understanding of how APOL1 risk variants contribute to renal cytotoxicity has increased. Some of the proposed mechanisms for kidney disease are biologically plausible for cells and tissues relevant to cardiovascular disease (CVD), but cardiovascular studies published since 2014 have reported conflicting results regarding APOL1 risk variant association with cardiovascular outcomes. In the past year, several studies have also contributed conflicting results from different types of study populations.

SUMMARY

Heterogeneity in study population and study design has led to differing reports on the role of APOL1 nephropathy risk variants in CVD. Without consistently validated associations between these risk variants and CVD, mechanistic studies for APOL1's role in cardiovascular biology lag behind.

In silico modeling of the dynamics of low density lipoprotein composition via a single plasma sample

Lipoproteins play a key role in the development of CVD, but the dynamics of lipoprotein metabolism are difficult to address experimentally. This article describes a novel two-step combined in vitro and in silico approach that enables the estimation of key reactions in lipoprotein metabolism using just one blood sample. Lipoproteins were isolated by ultracentrifugation from fasting plasma stored at 4°C. Plasma incubated at 37°C is no longer in a steady state, and changes in composition may be determined. From these changes, we estimated rates for reactions like LCAT (56.3 µM/h), β-LCAT (15.62 µM/h), and cholesteryl ester (CE) transfer protein-mediated flux of CE from HDL to IDL/VLDL (21.5 µM/h) based on data from 15 healthy individuals. In a second step, we estimated LDL's HL activity (3.19 pools/day) and, for the very first time, selective CE efflux from LDL (8.39 µM/h) by relying on the previously derived reaction rates. The estimated metabolic rates were then confirmed in an independent group (n = 10). Although measurement uncertainties do not permit us to estimate parameters in individuals, the novel approach we describe here offers the unique possibility to investigate lipoprotein dynamics in various diseases like atherosclerosis or diabetes.

The interaction between beta-3 adrenergic receptor polymorphism and obesity to periodontal disease in community-dwelling elderly Japanese

OBJECTIVES

The purpose of this study was to elucidate whether the association between beta-3 adrenergic receptor polymorphism and periodontal disease is modified by body weight.

MATERIAL AND METHODS

We enrolled 332 postmenopausal women and determined their HbA1C levels (%) and beta-3 adrenergic receptor (rs4994) genotypes. Periodontal parameters including clinical attachment level (CAL) were measured. After selecting subjects for each body mass index (BMI) level, the prevalence rate ratio (PRR) by multiple Poisson regression analysis was calculated to evaluate the relationship between periodontal disease and beta-3 adrenergic receptor polymorphism. The number of sites with CAL≥6 mm was used as a dependent variable, and beta-3 adrenergic receptor genotype [categorized as Arg non-carriers (reference) or Arg carriers], age (y) and HbA1C (%) were adopted as independent variables. We converted the number of probing sites (n) to an offset variable.

RESULTS

The PRR of the beta-3 adrenergic receptor genotype for the number of sites of CAL≥6 mm showed a positive association in subjects with BMI≥25.0 and increased markedly with BMI. The PRR in subjects with BMI≥30 was 3.10 (p < 0.0001).

CONCLUSION

This study indicates a positive association between periodontal disease and the beta-3 adrenergic receptor genotype in obese individuals.

Non-high-density lipoprotein cholesterol changes in middle-aged obese men with and without metabolic syndrome during weight loss

Non-high-density lipoprotein (non-HDL-C) is the best predictor of coronary artery disease and stroke. Studies have shown that weight loss decreases non-HDL-C levels. However, whether diet-induced weight loss in individuals with and without metabolic syndrome causes a reduction in non-HDL-C levels remains unclear. We investigated the effects of weight loss on non-HDL-C levels in 34 middle-aged obese men with and without metabolic syndrome classified using National Cholesterol Education Panel Adult Treatment Panel III criteria (metabolic syndrome, n = 17; non-metabolic syndrome, n = 17). We conducted a 12-week dietary intervention using a low-carbohydrate, -fat, and -protein diet to reduce body weight. A significant decrease in body weight and body mass index in both groups was observed. However, the non-HDL-C level after weight loss was significantly decreased in the metabolic syndrome group (151.9 ± 6.8 to 131.4 ± 6.2 mg/dL, P < 0.01) but not in the non-metabolic syndrome group (152.1 ± 8.2 to 141.2 ± 8.1 mg/dL, P > 0.05). Levels of apolipoprotein AII and B, but not AI, were similarly decreased in both groups (P > 0.05). Pearson correlation analysis showed that the change in non-HDL-C levels in the metabolic syndrome group was strongly associated with levels of total cholesterol, fasting insulin, and alanine and aspartate transaminase, as well as homeostatic model assessment index, diastolic blood pressure, and maximal oxygen uptake (P < 0.05). These results demonstrated that diet-induced weight loss without physical activity decreases non-HDL-C levels, an important factor associated with changes in cardiorespiratory fitness and insulin sensitivity, in obese individuals with metabolic syndrome.

Association of CETP and LIPC Gene Polymorphisms with HDL and LDL Sub-fraction Levels in a Group of Indian Subjects: A Cross-Sectional Study

There is an increasing interest to understand the molecular basis of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) subfractions and their association with coronary artery disease (CAD). The formation of these subfractions is greatly influenced by hepatic lipase (HL) and cholesteryl ester transfer protein (CETP) enzymes. To identify genetic markers influencing LDL and HDL subfractions and their role in CAD we performed a case-control genetic association study on 117 healthy controls and 119 angiographically verified CAD patients. Biochemical analysis was performed using standard assays. HDL-C and LDL-C subfractions were estimated using precipitation methods. Genotyping of C-514T (rs1800588) in the LIPC gene for HL and I405V (rs5882) in the CETP gene was done using PCR-based restriction enzyme analysis and sequencing. Both the polymorphisms were not associated with CAD. The C-514T was associated with increased HDL3-C levels in controls (P = 0.049). The I405V polymorphism was found to be associated with low levels of small dense, LDL (P = 0.038). A multiple regression analysis showed that the effects were dependent on gender and triglyceride levels. We conclude that these polymorphisms are not associated with CAD but are important determinants of HDL-C and small dense LDL particles in our population.

Prevalence of dyslipidemia and associated factors in the Yi farmers and migrants of Southwestern China

There are scant data on serum lipid profile in the Yi people in China. The Yi farmers and migrants provide an unusual opportunity to estimate effects of environmental factors on serum lipid levels. We conducted a cross-sectional study in the Yi people to estimate prevalence of dyslipidemia and associated factors. It was found that prevalence of high total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), abnormal ratio of TC/HDL-C and low high-density lipoprotein-cholesterol (HDL-C) were 1.82%, 5.07%, 1.56%, 9.30% and 39.47%, respectively in the Yi farmers. And those in the Yi migrants were 4.81%, 22.21%, 3.24%, 26.56% and 40.53%. Prevalence of dyslipidemia increased with time period in the Yi farmers after their emigrating to urban areas for less than 25 years, except high TC. It was also found that prevalence of dyslipidemia of the Yi migrants increased with time period before their emigration, including hypertriglyceridemia, low HDL-C and high ratio of TC/HDL-C. Their body mass index (BMI), history of type 2 diabetes mellitus (T2DM), gender, ever alcohol drinking and physical activity all were associated with dyslipidemia, but no factors associated with high LDL-C was found. In conclusion, all these results suggest that the Yi migrants have a higher prevalence of dyslipidemia than the Yi farmers do, which possibly can attribute to their urbanized lifestyles.

Sex and race differences in the prevalence of fatty liver disease as measured by computed tomography liver attenuation in European American and African American participants of the NHLBI family heart study

BACKGROUND AND AIMS

Liver attenuation (LA) [Hounsfield Units (HU)] by computed tomography is a validated quantitative measure that is inversely related to liver fat burden. We examined race and sex differences on the distribution of LA [one of the first stages of fatty liver disease (FLD)] and the predictors of these mean differences in European American (EA) and African American (AA) participants of the Family Heart Study.

MATERIALS AND METHODS

A total of 1242 (1064 EA, 178 AA) and 1477 (1150 EA, 327 AA) men and women, respectively, underwent computed tomography examination from which LA and abdominal adipose volume were measured. LA (adjusted for phantom and field center) was the dependent variable in linear mixed models (to control for family relatedness) that tested for mean differences by race and by sex. Independent explanatory variables included age, BMI, visceral adipose tissue volume (VAT), subcutaneous adipose tissue volume, alcohol consumption, triglyceride, HDL-cholesterol, and insulin resistance.

RESULTS

Mean LA varied significantly by sex, [(men) 57.76±10.03 HU and (women) 60.03±10.91 HU, P=0.0002], but not by race. Higher LA was associated with older age, whereas higher values of VAT, triglycerides, and insulin resistance were associated with lower LA in men and women. In contrast, alcohol consumption and BMI were associated with lower LA only among men. In analyses stratified by race, LA was associated with alcohol consumption, VAT, and insulin resistance in both EA and AA and with age, BMI, and HDL-cholesterol in EA participants only.

CONCLUSIONS

Our study findings confirm that there are important sex differences and race by sex interaction effects on the distribution of LA, the prevalence of FLD, and on the influence of metabolic risk factors on LA and FLD.

Case series of type III hyperlipoproteinemia in children

Type III hyperlipoproteinemia (type III HLP) rarely manifests in childhood. Long-term follow-up (37 years) of the first patient revealed hypothyroidism at diagnosis requiring thyroxine replacement, palmar xanthomas requiring surgical removal, splenomegaly requiring splenectomy, 18 episodes of pancreatitis and premature coronary artery disease. Investigation revealed an apolipoprotein E phenotype of E2/E2 and partial lipoprotein lipase deficiency. Investigation of the second patient revealed a combination of apoE2/E2 phenotype and heterozygous familial hypercholesterolaemia. The third patient had a complete deficiency of lipoprotein lipase activity, an abnormal thyroid stimulating hormone on diagnosis (with subsequent normalisation without treatment), and apoE2/E2 phenotype. Type III HLP is a serious disorder with lifelong consequences of premature vascular disease and recurrent pancreatitis. Early presentation of disease in our patients was associated with additional precipitating factors. Drug treatment of paediatric type III HLP is indicated if dietary modifications alone are insufficient in managing the dyslipidaemia.

Influence of body mass index, gender, and Hispanic ethnicity on physical activity in urban children

PURPOSE

This community-based participatory research study examined the association between overweight status and activity among Hispanic urban, school-age children.

DESIGN AND METHODS

In a sample of 140 children, activities were assessed using the Youth Risk Behavior Survey's questions about physical activity (PA) and team sports.

RESULTS

Thirty-nine percent were overweight (body mass index [BMI] >85%). Normal-weight children had higher levels of PA and team sports. Females had lower levels of PA and team sports. Significant associations included BMI and sports team participation, and BMI and Hispanic ethnicity.

PRACTICE IMPLICATIONS

Nurses should be aware that Hispanic urban children are at risk for lower activity.

Ethnicity/race, use of pharmacotherapy, scope of physician-ordered cholesterol screening, and provision of diet/nutrition or exercise counseling during US office-based visits by patients with hyperlipidemia

BACKGROUND

Elevation of serum cholesterol, or hyperlipidemia, is recognized as one of the major modifiable risk factors in the development of atherosclerosis and cardiovascular disease. On a US population basis, there has been a downward trend in total- and LDL-cholesterol levels, and an increase in cholesterol screening. Nevertheless, previous research suggests that there remain racial/ethnic disparities in the access to and quality of care for hyperlipidemia.

OBJECTIVE

The aim of this study was to examine the extent of racial/ethnic disparities in the provision of pharmacotherapy, cholesterol screening and diet/nutrition or exercise counseling during US office-based physician-patient encounters (visits) by patients with hyperlipidemia.

METHODS

We examined data from the 2005 US National Ambulatory Medical Care Survey for office-based visits for hyperlipidemia for patients aged > or =20 years in terms of prescribing for hyperlipidemia, and the ordering/provision of cholesterol testing, diet/nutrition counseling, and exercise counseling.

RESULTS

Use of pharmacotherapy for hyperlipidemia varied by ethnicity/race (chi2, p < 0.05). Physician-ordered/provided cholesterol screening occurred in 44.2% of all office-based visits; 46.5% for Whites, 35.4% for Blacks, and 30.3% for Hispanics (chi2, p < 0.05). Diet/nutrition counseling was ordered/provided in 39.7% of office-based visits; 40.4% for Whites, 32.6% for Blacks, and 39.0% for Hispanics (chi2, p < 0.05). Exercise counseling was ordered/provided in 32.1% of office-based visits; 32.7% for Whites, 27.2% for Blacks, and 30.6% for Hispanics (chi2, p < 0.05).

CONCLUSIONS

These findings reveal a disparity in use of pharmacotherapy for hyperlipidemia, physician-ordered/provided cholesterol screening, diet/nutrition counseling, and exercise counseling by ethnicity/race. Further research is required to discern, in greater detail, reasons for the observed differences reported, and to ensure equitable access to established standards of care.

Associations between dietary macronutrient intake and plasma lipids demonstrate criterion performance of the Multi-Ethnic Study of Atherosclerosis (MESA) food-frequency questionnaire

The validity of self-reported dietary intake is critical to the design and interpretation of diet-disease investigations. For many nutrients, there are no ideal methods to establish validity, given correlated error between reference and assessment tools, and constraints on time and resources available to perform such studies. Therefore, we quantified associations between macronutrient intakes and plasma HDL-cholesterol and TAG, relying on known associations between these factors to test the criterion validity of the FFQ used in the Multi-Ethnic Study of Atherosclerosis (MESA). Baseline dietary macronutrient intakes (derived from 120-item FFQ), and fasting plasma HDL and TAG were measured in 4510 MESA participants, aged 45-84 years. After adjusting for non-dietary factors known to affect plasma lipid concentrations, greater carbohydrate intake was associated with lower HDL and higher TAG (beta per 5-unit change in percentage energy intake from carbohydrate = - 5 (se 1) mg/l (P < 0.001) for HDL and 15 (se 6) mg/l (P = 0.008) for TAG), whereas higher energy intake from fat was associated with higher HDL and lower TAG (beta per 5-unit change in percentage energy from fat = 3.7 (se 2) mg/l (P = 0.01) for HDL and beta = 19 (se 7) mg/l (P = 0.004) for TAG). Associations of dietary carbohydrate and fat intakes with HDL and TAG concentrations were consistent with previous studies, demonstrating criterion validity of these dietary measures in the MESA.

LIPC variants in the promoter and intron 1 modify HDL-C levels in a sex-specific fashion

We previously reported linkage for plasma levels of high-density lipoprotein cholesterol (HDL-C) on 15q21 in Caucasian families from the National Heart, Lung, and Blood Institute Family Heart Study (NHLBI FHS). Hepatic lipase gene (LIPC), which has a major role in lipoprotein metabolism, resides within the linkage region and constitutes an obvious candidate gene. While hepatic lipase is a known player in HDL metabolism, the relationship between common LIPC variants and HDL-C levels remains unclear. In the current study, we employed population-based and family-based tests of association with both quantitative HDL-C levels and a dichotomous dyslipidemia trait (affected men: HDL<40 mg/dL and women: HDL<50 mg/dL, denoted as low HDL). We genotyped 19 tag-SNPs spanning 139.9 kb around the LIPC in the 591 families (2238 subjects). Strong association in a proxy-promoter 5' SNP (rs261342) and HDL-C levels was detected in women, but not in men. The less common allele was associated with an increase of approximately 14% in HDL-C levels, and a decrease of approximately 30% in risk of low HDL. In addition, strong association in women of an intron 1 SNP (rs12593008) and low HDL and moderate association in men (rs8028759) with both HDL-C levels and low HDL phenotype were found and may represent either functional single nucleotide polymorphisms (SNPs), or more likely, SNPs in linkage disequilibrium with functional variants. Because of the association of lipid abnormalities with diabetes, and other lifestyle parameters, we also performed association analyses using different covariate adjustments as well as strategically selected sub-samples. The sex-specific association of rs261342, rs12593008 or rs8028759 remained substantially the same through these analyses. Finally, we found that a common haplotype was overtransmitted to offspring with low HDL-C. The sex-specific associations found in our study could be due to the interactions with the endogenous hormonal environment, lifestyle and/or genetic factors, although the underlying physiologic mechanisms are not understood.

High density lipoprotein-cholesterol levels increase with age in American women but not in Hong Kong Chinese women

OBJECTIVES

High-density lipoprotein (HDL) cholesterol is a powerful cardiovascular risk factor. Important gender and ethnic differences in plasma HDL levels exist and warrant investigation.

DESIGN

Cross-sectional survey in two different general populations. Patients 7700 participants of the National Health and Nutrition Examination Survey (NHANES) 1999-2002 and 1944 participants of the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2) 2000-2004.

MEASUREMENTS

Plasma HDL levels.

RESULTS

Plasma HDL levels were higher in women than in men in both populations. In the United States women, it increased with age, whereas in Chinese women, it declined with age and converged with male HDL levels. In the United States, 37.1 +/- 1.2% men and 38.9 +/- 1.1% women had low HDL levels. In Hong Kong, 34.3 +/- 1.6% men and 34.5 +/- 1.5% women had low HDL levels. In Americans, the independent predictors of low HDL levels were lower age, being non-Mexican Hispanic, waist circumference, triglycerides and not drinking alcohol in men, and lower age, being Hispanic, waist circumference, triglycerides, current smoking and not drinking alcohol in women. In Hong Kong Chinese, the independent predictors of low HDL levels were body mass index, triglycerides, current smoking and not drinking alcohol in men, and lower age, waist circumference, triglycerides, diabetes and former smoking in women.

CONCLUSIONS

The decline in plasma HDL with age in Chinese women is opposite to that seen in American women. The increased cardiovascular risk in elderly Chinese women requires further study.

A novel method for measuring human lipoprotein lipase and hepatic lipase activities in postheparin plasma

The objective of this study was to establish a new lipoprotein lipase (LPL) and hepatic lipase (HL) activity assay method. Seventy normal volunteers were recruited. Lipase activities were assayed by measuring the increase in absorbance at 546 nm due to the quinoneine dye. Reaction mixture-1 (R-1) contained dioleoylglycerol solubilized with lauryldimethylaminobetaine, monoacylglycerol-specific lipase, glycerolkinase, glycerol-3-phosphate oxidase, peroxidase, ascorbic acid oxidase, and apolipoprotein C-II (apoC-II). R-2 contained Tris-HCl (pH 8.7) and 4-aminoantipyrine. Automated assay of lipase activities was performed with an automatic clinical analyzer. In the assay for HL + LPL activity, 160 microl R-1 was incubated at 37 degrees C with 2 microl of sample for 5 min, and 80 microl R-2 was added. HL activities were measured under the same conditions without apoC-II. HL and LPL activities were also measured by the conventional isotope method and for HL mass by ELISA. Lipase activity detected in a 1.6 M NaCl-eluted fraction from a heparin-Sepharose column was enhanced by adding purified apoC-II in a dose-dependent manner, whereas that eluted by 0.8 M NaCl was not. Postheparin plasma-LPL and HL activities measured in the present automated method had high correlations with those measured by conventional activity and mass methods. This automated assay method for LPL and HL activities is simple and reliable and can be applied to an automatic clinical analyzer.

Lower HDL-cholesterol among healthy middle-aged Japanese-Brazilians in São Paulo compared to Natives and Japanese-Brazilians in Japan

Blood lipid levels are determined by a combination of genetic and environmental factors. Higher than average values of high-density lipoprotein cholesterol (HDL-cholesterol) have been observed in people of Japanese ethnicity. The aim of this study was to investigate whether Japanese immigrants to Brazil and subsequent generations maintain the protective benefits associated with higher levels of HDL-cholesterol, and to examine the potential associations between HDL-cholesterol and a variety of other blood lipids, anthropometric and lifestyle factors. Healthy men and women aged 35 years and older who were Native Japanese (n = 198) or Japanese-Brazilians (JB) living in São Paulo, Brazil (n = 198) and in some Japanese cities (n = 246) were investigated. Anthropometric variables, blood lipids including HDL-cholesterol, and lifestyle factors were assessed. Serum HDL-cholesterol was observed to be lower for JB in São Paulo (both women and men) compared with Natives and JB in Japan. Among the groups, triglycerides, waist circumference, LDL-cholesterol, meat intake, stress, and smoking were observed to be independently negatively associated with HDL-cholesterol, whereas total cholesterol, fish intake, and physical activity were positively associated. Lower levels of HDL-cholesterol among both men and women of JB in São Paulo compared with both other groups were confirmed even after lifestyle adjustments. Our findings highlight the significantly lower levels of HDL-cholesterol among Japanese-Brazilians living in São Paulo city compared to Japanese-Brazilians and Native Japanese residing in Japan. Although several lifestyle factors were found to be significantly associated with HDL-cholesterol, they cannot adequately explain the role of the Brazilian cultural environment on HDL-cholesterol levels.

CETP (cholesteryl ester transfer protein) promoter −1337 C>T polymorphism protects against coronary atherosclerosis in Japanese patients with heterozygous familial hypercholesterolaemia

CETP (cholesteryl ester transfer protein) and HL (hepatic lipase) play a role in the metabolism of plasma lipoproteins, but the effects of CETP and LIPC (gene encoding HL) genotypes on coronary atherosclerosis may be dependent on LDL (low-density lipoprotein)-receptor activity. Recently, the −1337 C>T polymorphism in the CETP gene has been reported in REGRESS (Regression Growth Evaluation Statin Study) to be a major determinant of promoter activity and plasma CETP concentration. In the present study, we have investigated the effects of the CETP promoter −1337 C>T and LIPC promoter −514 C>T polymorphisms on serum lipid profiles and risk of coronary atherosclerosis in 206 patients (154 males) with heterozygous FH (familial hypercholesterolaemia). To evaluate coronary atherosclerosis, we used CSI (coronary stenosis index) calculated from coronary angiograms. The CETP −1337 T allele was less frequent in subjects with a CSI ≥14 (mean value) in the group with coronary artery disease (P=0.04, as determined by χ2 test). ANOVA revealed that HDL-C (high-density lipoprotein-cholesterol) and triacylglycerol (triglyceride) levels were not significantly higher in the presence of the CETP promoter −1337 T allele. Combined with LIPC promoter polymorphisms, HDL-C levels were highest and CSI were lowest with CETP −1337 CT+TT and LIPC −514 CC genotypes, but a significant interaction was not shown. A multiple logistic regression analysis revealed that, in patients with coronary atherosclerosis, the CETP− 1337 CC genotype was a significant genetic risk factor in FH (odds ratio=2.022; P=0.0256). These results indicate that the CETP promoter −1337C>T polymorphism is associated with the progression of coronary atherosclerosis in Japanese patients with FH, independent of HDL-C and triacylglycerol levels.

Lipoprotein subclass and particle size differences in Afro-Caribbeans, African Americans, and white Americans: associations with hepatic lipase gene variation

Despite a higher prevalence of coronary heart disease risk factors, men of African origin have less coronary atherosclerosis, as measured by coronary calcification, than whites. In part, this is thought to be because of the less atherogenic lipoprotein profile observed in men of African origin, characterized by lower triglycerides and higher high-density lipoprotein (HDL) cholesterol. We hypothesized that the -514C>T polymorphism in the hepatic lipase gene (LIPC) plays a significant role in determining a less atherogenic lipoprotein profile observed in men of African origin. Previously conducted studies of the LIPC -514C>T polymorphism in African Americans may have been confounded by a higher level of European admixture; in addition, the results from these studies do not necessarily apply to other African populations because gene-environment interactions may differ. Thus, we compared nuclear magnetic resonance spectroscopy-measured lipoprotein subclass patterns and LIPC -514C>T genotypes in population-based samples of older white American (n = 532) and African American (n = 97) men from the Cardiovascular Health Study to those among older, less admixed, Afro-Caribbean men (n = 205) from the Tobago Health Study. Men of African origin had a more favorable lipoprotein profile than whites. In addition, levels of low-density lipoprotein cholesterol, total cholesterol, and triglyceride, and large and small very low-density lipoprotein, small low-density lipoprotein, as well as very low-density lipoprotein particle size, were remarkably lower in Afro-Caribbean men than in either African American or white men. The frequency of the LIPC -514T allele was much higher in Afro-Caribbeans (0.57) and in African Americans (0.49) than in whites (0.20). The -514T allele in both populations of African origin, but not in whites, was associated with elevated large HDL and greater HDL size. Our findings indicate that the higher frequency of the LIPC -514T allele found in men of African origin living in different environments significantly contributes to the more favorable distribution of HDL subclasses compared with whites.

Hepatic lipase gene variant -514C>T is associated with lipoprotein and insulin sensitivity response to regular exercise: the HERITAGE Family Study

We investigated the associations between the hepatic lipase gene (LIPC) -514C>T polymorphism and lipases, lipoproteins, and insulin sensitivity (Si) responses to exercise training. Hepatic lipase and lipoprotein lipase activities, plasma lipoprotein levels, and Si were measured in the sedentary state and post-exercise training in the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study (n=662). The LIPC -514C allele frequency was 0.516 (blacks) and 0.796 (whites). Baseline and post-exercise training hepatic lipase activities were 40% higher in CC homozygotes (P < 0.0001) in both races. Black CC homozygotes had lower baseline lipoprotein lipase activity, HDL cholesterol, HDL3, and apolipoprotein (apo)A-1 concentrations. White CC homozygotes had lower baseline HDL cholesterol, apoA-1, LDL cholesterol, and apoB levels that remained low post-exercise training. Baseline Si was not associated with the LIPC genotypes. However, training-induced improvements in Si both in blacks and whites were greater in CC homozygotes (+1.25 +/- 0.2 and +0.22 +/- 0.2 microU.min(-1).ml(-1)) than in the TT genotype (+0.27 +/- 0.3 and -0.97 +/- 0.3 microU.min(-1).ml(-1)) (P = 0.008 and P = 0.002, respectively). The LIPC -514C allele was associated with higher hepatic lipase activity in sedentary and physically active states and better Si responses to regular exercise both in black and white individuals. The benefits from an exercise program on Si are likely to be substantial in the general population given the high frequency of the LIPC -514C allele, particularly in whites.

Interactions between the -514C->T polymorphism of the hepatic lipase gene and lifestyle factors in relation to HDL concentrations among US diabetic men

BACKGROUND

Low plasma HDL-cholesterol concentrations are a hallmark of diabetic dyslipidemia. A common polymorphism (-514C-->T) of the hepatic lipase gene (LIPC), which accounts for up to 30% of the variation in hepatic lipase activity, has been associated with low hepatic lipase activity and high HDL-cholesterol concentrations.

OBJECTIVE

We examined the association between this polymorphism and plasma HDL-cholesterol concentrations and evaluated whether this association was modified by adiposity and dietary fat intake.

DESIGN

We followed men aged 40-75 y who participated in the Health Professionals Follow-Up Study in 1986. Among 18 159 men who returned blood samples by 1994, 780 had confirmed type 2 diabetes at blood drawing or during follow-up to 1998 and were free of cardiovascular disease at blood drawing.

RESULTS

After adjustment for age, smoking, alcohol consumption, fasting status, glycated hemoglobin concentration, physical activity, and body mass index, HDL-cholesterol concentrations were significantly higher in men with the C/T or T/T genotype than in those with the C/C genotype (adjusted x: 40.9 and 38.8 mg/dL, respectively; P = 0.01). We observed significant LIPC -514 polymorphism x body mass index and LIPC -514 polymorphism x saturated fat intake interactions for HDL-cholesterol concentrations (P = 0.003 for both). The T allele was associated with higher HDL-cholesterol concentrations only in men who were not overweight or who had higher saturated fat intake.

CONCLUSION

Our study suggests that the effects of -514C-->T of the LIPC gene on HDL concentrations were modified by saturated fat intake and obesity.

Ethnic differences in the formation of small LDL particles in Asians: a comparison of Koreans, Japanese and Mongolians

BACKGROUND

The presence of small, dense LDL particles has been recognized as an independent risk factor for coronary heart disease (CHD) but is not directly representative of CHD mortality rate beyond any given population. We investigated whether such inconsistency between three Asian ethnic groups might have arisen from anthropometric and metabolic factors.

DESIGN

We conducted a cross-sectional survey among adult Koreans (412), Japanese (453) and Mongolians (253).

RESULTS

The prevalence of small LDL particles was 36% in the Koreans, 21% in the Japanese and 7% in the Mongolians. Multiple logistic regression analysis revealed plasma triglyceride (TG) levels to be the strongest determinant of small LDL particle size in all three groups, with sex, HDL-cholesterol and non-HDL-C being other ethnic-specific significant determinants. Body mass index (BMI), FFA and insulin resistance were not significant factors in the regression analysis. Of the subjects with low TG levels (< 133 mg dL(-1)), 25% of the Koreans and 10% of the Japanese, but no Mongolians, had small LDL particles.

CONCLUSIONS

Results of the present study suggest that traditionally, high-carbohydrate diets in Korea and Japan possibly contribute to higher TG-levels compared with BMI-matched Mongolians, and to the formation of small LDL particles, even in instances of low TG levels.

What is the contribution of obesity to the metabolic syndrome?

Many prospective studies show that obesity is accompanied by increased risk for cardiovascular disease. Obesity affects metabolism of lipids and glucose, regulation of blood pressure, thrombotic and fibrinolytic processes, and inflammatory reactions. Multiple aberrations exist in each of these systems; obesity acting alone probably is not sufficient to produce full-blown metabolic syndrome. There must be other factors, including genetic and aging factors. It is difficult to sort out all pathogenic factors that link obesity to cardiovascular disease risk. It is worthwhile to investigate individually the components of the obesity-induced metabolic syndrome for their atherogenic potential, because out of that investigation likely will come new targets for clinical or public health intervention to reduce the risk for cardiovascular disease.