Factors associated with high density lipoprotein cholesterol in a population with high high density lipoprotein cholesterol levels

Prevalence of High HDL Cholesterol and Its Associated Factors Among Tunisian Women of Childbearing Age: A Cross-Sectional Study

The protective role of high high-density lipoprotein cholesterol (HDL-C) against cardiovascular risk has been questioned recently. Due to the increasing trend of cardiovascular diseases (CVD) in Tunisia, this study aimed to determine the prevalence of high HDL-C and its associated factors in Tunisian women of childbearing age. A cross-sectional survey was conducted among a subsample of 1689 women, aged 20 to 49 years, in the Great Tunis region. Data on socio-demographic and lifestyle factors were collected by a questionnaire. Overall adiposity was assessed by body mass index (BMI). All biological variables were assayed in blood samples coated with anticoagulant ethylene diamine tetra acetic acid (EDTA) by enzymatic methods. Stata software (2015) was used for data management and statistical analysis. High HDL-C values were recorded in 26.6% of selected women. After adjustment for all socio-demographic and lifestyle factors, age, hypertension, and smoking were negatively associated with high HDL-C levels, while family history of cancer was positively associated with high HDL-C in women. An additional investigation on the relationship between high HDL-C and cancer risk should be performed due to controversial results.

Changes in High-Density Lipoprotein Cholesterol Levels in Relation to Coffee Consumption Among Taiwanese Adults

Purpose

High-density lipoprotein cholesterol (HDL-C) is essential for cardiometabolic health. Coffee consumption influences the body’s ability to regulate serum lipid profile. Although there is extensive information on coffee and cholesterol, not much is known whether changes in HDL-C concentrations are affected by coffee with or without flavoring substances.

Materials and Methods

Using historical data collected from 1272 participants in Li-Shin (Landseed) International Hospital in Northern Taiwan, we examined the relationship between HDL-C and consumption of plain black coffee with and without additives. Data on coffee consumption between 2006 and 2019 were collected based on self-reported questionnaires while HDL-C measurements were obtained from the electronic medical records of the hospital. t-test, chi-square test and multivariate linear regression analysis were used for analysis.

Results

In our primary analysis, we found that coffee consumption of ≥5 cups per week was positively associated with HDL-C (β = 1.9586, p=0.0442) compared with the lowest level (<1 cup/week) of consumption. We found in a separate model that higher (≥5 cups/week) or lower (1–4 cups/week) consumption of plain black coffee without additives was associated with higher HDL-C. The corresponding β values were 4.0674 (p = 0.0007) and 4.1253 (p = 0.0008), respectively. However, HDL-C levels were not affected by coffee with additives.

Conclusion

We found that consumption of black coffee without additives was associated with higher concentrations of HDL-C among Taiwanese adults over the age of 30. However, HDL-C levels did not change significantly among individuals who consumed black coffee with additives.

Association of rheumatoid arthritis susceptibility gene with lipid profiles in patients with rheumatoid arthritis

OBJECTIVE

RA patients have an increased risk of cardiovascular (CV) disease, although the mechanisms are unclear. As RA and CV disease may be associated through lipid profiles, we examined whether single nucleotide polymorphisms (SNPs) associated with RA susceptibility were associated with low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride (TG) levels in RA subjects.

METHODS

Patients (n = 763) enrolled in the Veterans Affairs RA registry who were not on hydroxymethylglutaryl-CoA reductase inhibitor were genotyped for human leukocyte antigen shared epitope (HLA-DRB1-SE) and SNPs in the following genes: CTLA-4 (cytotoxic T-lymphocyte antigen 4), IL-10, PTPN22 (protein tyrosine phosphatase, non-receptor type 22), REL (c-Rel), STAT4 (signal transducer and activator of transcription protein), TNF- and TRAF1 (TNF receptor-associated factor 1). Other covariates included patient characteristics (age, gender, race, smoking status, education, BMI, modified CharlsonDeyo comorbidity index), CV characteristics (hypertension, diabetes, alcohol abuse), pharmacologic exposures (MTX, anti-TNF, glucocorticoids) and RA severity/activity markers (RA disease duration, mean DAS, CRP, RF positivity, anti-CCP positivity). Multivariate linear regression was performed to determine the factors associated with LDL, HDL and TG levels.

RESULTS

The REL SNP rs9309331 homozygous minor allele was associated with higher LDL levels. Caucasian race and increasing BMI were associated with lower HDL. Factors associated with higher TG were diabetes, Caucasian race and higher BMI.

CONCLUSION

The REL SNP rs9309331 was associated with LDL levels in our study. This association is a possible explanation of the increased risk of RA patients for CV disease and requires further inquiry.

Development and validation of a short questionnaire to assess sodium intake

Objectives

To develop and validate a short food-frequency questionnaire to assess habitual dietary salt intake in South Africans and to allow classification of individuals according to intakes above or below the maximum recommended intake of 6 g salt day−1.

Design

Cross-sectional validation study in 324 conveniently sampled men and women.

Methods

Repeated 24-hour urinary Na values and 24-hour dietary recalls were obtained on three occasions. Food items consumed by >5% of the sample and which contributed ≥50 mg Na serving−1 were included in the questionnaire in 42 categories. A scoring system was devised, based on Na content of one index food per category and frequency of consumption.

Results

Positive correlations were found between Na content of 35 of the 42 food categories in the questionnaire and total Na intake, calculated from 24-hour recall data. Total Na content of the questionnaire was associated with Na estimations from 24-hour recall data (r = 0.750; P < 0.0001; n = 328) and urinary Na (r = 0.152; P = 0.0105; n = 284). Urinary Na was higher for subjects in tertile 3 than tertile 1 of questionnaire Na content (P < 0.05). Questionnaire Na content of <2400 and ≥2400 mg day−1 equated to a reference cut-off score of 48 and corresponded to mean (standard deviation) urinary Na values of 145 (68) and 176 (99) mmol day−1, respectively (P < 0.05). Sensitivity and specificity against urinary Na ≥100 and <100 mmol day−1 was 12.4% and 93.9%, respectively.

Conclusion

A 42-item food-frequency questionnaire has been shown to have content-, construct- and criterion-related validity, as well as internal consistency, with regard to categorising individuals according to their habitual salt intake; however, the devised scoring system needs to show improved sensitivity.

Cytochrome P450--physiological key factor against cholesterol accumulation and the atherosclerotic vascular process

In the early 1960s liver cytochrome P450 (P450) was known as an enzyme in drug metabolism. By the late 1970s, P450 induction was associated with elevation of plasma high-density lipoprotein cholesterol and apolipoprotein AI indicating a reduced risk of atherosclerotic disease. Later on, 57 human P450 genes have been identified. One P450 enzyme participates in cholesterol synthesis, and several others catabolize it to oxysterols and other metabolites. Oxysterols are physiological ligands specific for liver X receptors (LXRs) in the activation of ATP-binding cassette (ABC) transporter and other cholesterol-lowering genes. Elevation of cholesterol leads to an endogenous induction of P450 and consequently to enhanced generation of oxysterols and activation of genes coding proteins which efflux cholesterol out of cells, transport it to the liver, catabolize and excrete cholesterol into bile, and prevent absorption of cholesterol in the intestine in the processes that maintain cellular cholesterol homeostasis and protect arteries from atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) co-operate with LXRs and ABC transporters in cholesterol regulation. Secretion of oxysterol is a direct pathway for cellular cholesterol elimination. Several compounds induce P450 and other genes regulating cholesterol balance and prevent or regress atherosclerosis, whereas inhibition of P450 blocks oxidative reactions, promotes cholesterol accumulation, and enhances the atherosclerotic vascular process.

Secondary data analyses of dietary surveys undertaken in South Africa to determine usual food consumption of the population

Objective:

The primary objective of this study was to generate a reference table of food items and average amounts of these items consumed by South Africans, for the Department of Health. The reference table was required to be representative of foods and beverages eaten frequently by children and adults from all age and ethnic groups in order for the Department of Health to test for contaminants in these foods.

Design:

The National Food Consumption Survey (NFCS) served as a framework for compiling data on children since this was a national representative survey of 1–9-year-old children undertaken in South Africa in 1999. However, there has never been a national dietary survey on adults in South Africa. Consequently the data had to be extrapolated from existing isolated surveys on adults. Secondary data analysis was conducted on existing dietary databases (raw data) obtained from surveys undertaken on adults in South Africa between 1983 and 2000. Available datasets were regional and independent, and were not individually representative of the South African diet. It was therefore necessary to use different statistical methods, including factor analyses, weighting and correlations, to generate ethnic and geographic representative data for adults. Two methods were used: Method 1, which corresponded with results of the NFCS (over-sampled for low socio-economic status), and Method 2, which was based on ethnic proportions of the population.

Results:

The secondary data analyses generated food items most commonly consumed by the South African adult population (Method 1) in descending frequency of usage and average (mean) amount per day: maize porridge (78%/848 g), white sugar (77%/27 g), tea (68%/456 g), brown bread (55%/165 g), white bread (28%/163 g), non-dairy creamer (25%/6 g), brick margarine (21%/19 g), chicken meat (19%/111 g), full-cream milk (19%/204 g) and green leaves (17%/182 g). In 6–9-year-olds, maize porridge (72%/426 g), sugar (76%/23 g), tea (51%/258 g), full-cream milk (35%/171 g) and white bread (33%/119 g) were eaten most frequently. Similarly, in 1–5-year-olds, the foods consumed most frequently were maize porridge (80%/426 g), sugar (76%/21 g), tea (44%/224 g), full-cream milk (39%/186 g) and white bread (24%/83 g). In order to evaluate the validity of the adult data generated, kilojoule values of the individual food items (per capita) were compared with food balance sheets (FBSs). The comparison was favourable except that the FBSs had a higher overall energy intake per capita of between 22 and 28%.

Conclusion:

Reference tables of commonly consumed foods and beverages were generated at minimal cost based on secondary data analyses of past dietary surveys in different South African populations.

Characteristics predicting dyslipidemia in drug-naïve type 2 diabetes patients

BACKGROUND

Plasma lipid concentrations are related to a variety of attributes in obese subjects, but these relationships have not been extensively examined in type 2 diabetes patients.

METHODS

A cross-sectional survey was conducted on type 2 diabetes patients who had never been treated with antihypertensives, lipid-lowering agents, and oral antidiabetic drugs other than sulfonylureas. Statistical analysis was performed to search for the correlation between lipid profiles and various parameters.

RESULTS

Among diabetic men, the plasma triglyceride (TG) level was positively correlated with the waist-to-hip ratio (WHR) and alcohol consumption, whereas high-density lipoprotein cholesterol (HDL-C) was negatively correlated with age and body mass index (BMI). Obese persons and alcohol drinkers were more likely to need pharmacologic treatment for dyslipidemia. Among diabetic women, the plasma TG level was positively correlated with WHR and the duration of diabetes since diagnosis, while HDL-C was negatively correlated with WHR and BMI. The necessity of treatment for dyslipidemia increased with the duration of diabetes.

CONCLUSION

We recommend a more intensive monitoring of lipid levels in drug-naive diabetic patients who possess the characteristics of alcohol consumption or older age (men), long duration of diabetes (women), and higher BMI or WHR (both genders).

Diet and blood pressure in South Africa: Intake of foods containing sodium, potassium, calcium, and magnesium in three ethnic groups

OBJECTIVES

We investigated whether habitual intakes of sodium (Na), potassium, magnesium, and calcium differ across South African ethnic groups, assessed the proportion of Na intake, which is discretionary, and identified which food sources were the major contributors to Na intake.

METHODS

This was a cross-sectional study of 325 black, white, and mixed ancestry hypertensive and normotensive subjects. Three repeated 24-h urine samples were collected for assessment of urinary Na, and three corresponding 24-h dietary recalls were administered by trained fieldworkers. Blood pressure and weight were measured at each visit. Secondary analyses were performed on existing dietary databases obtained from four regional surveys undertaken in South African adults.

RESULTS

Mean urinary Na excretion values equated to daily salt (NaCl) intakes of 7.8, 8.5, and 9.5 g in black, mixed ancestry, and white subjects, respectively (P < 0.05). Between 33% and 46% of total Na intake was discretionary, and, of the non-discretionary sources, bread was the single greatest contributor to Na intake in all groups. Ethnic differences in calcium intake were evident, with black subjects having particularly low intakes. Urban versus rural differences existed with respect to sources of dietary Na, with greater than 70% of total non-discretionary Na being provided by bread and cereals in rural black South Africans compared with 49% to 54% in urban dwellers.

CONCLUSION

White South Africans have higher habitual intakes of Na, but also higher calcium intakes, than their black and mixed ancestry counterparts. All ethnic groups had Na intakes in excess of 6 g/d of salt, whereas potassium intakes in all groups were below the recommended level of 90 mM/d. Dietary differences may contribute to ethnically related differences in blood pressure.

Correlations between lipid levels and age, gender, glycemia, obesity, diabetes, and smoking

A low level of high-density lipoprotein cholesterol (HDL-C) is an important cardiovascular risk factor. Dietary measures and pharmacological agents are often not sufficient to reach the HDL-C target level of 40 mg/dl in patients with low baseline HDL-C. This study assesses the association between lipid levels and age, gender, body mass index (BMI), glycemia, diabetes and smoking and focuses on the parameters influencing HDL-C. In the town of Lede (Belgium) all patients aged between 45 and 64 years were invited during 1999 for a free of charge health check-up and blood test. Blood pressure, weight, length and smoking habits were recorded. Serum levels for glycemia and lipoproteins were determined. In total, 629 subjects attended for the check-up. In a logistic regression analysis age above 50 years was correlated with low HDL-C (OR = 2.27 CI = 1.10-4.68). Male gender was correlated with low HDL-C (OR = 3.85 CI = 1.77-8.43) and with high triglycerides (TG) (OR = 1.94 CI = 1.14-3.30). From the level of 90 mg/dl glycemia was correlated with low HDL-C (OR = 2.56 CI = 1.02-6.39) and high TG (OR = 2.12 CI = 1.16-4.06). Obesity was correlated with low HDL-C (OR = 2.36 CI = 1.18-4.71) and high TG (OR = 2.17 CI = 1.88-5.23). This study provides some evidence to sharpen the target levels for glycemia and BMI among patients with low HDL-C and high TG. For these patients, the target glycemia should be around 90 mg/dl and BMI around 25 kg/m2. Physical activity and diet are also important in the achievement of these target levels.

Effects of menopause and hormone replacement therapy on plasma lipids, lipoproteins and LDL-receptor activity

A cross-sectional study of ninety six women was conducted to examine the effect of menopause and hormone replacement therapy (HRT) on plasma lipids, lipoproteins and oxidation of low density lipoproteins. The sample consisted of 26 premenopausal women, 26 postmenopausal women taking no replacement hormones and 43 postmenopausal women on hormone replacement therapy. Postmenopausal women not taking replacement hormones had significantly higher plasma cholesterol, low density lipoprotein (LDL) cholesterol and lipoprotein[a] (Lp[a]) levels compared to premenopausal women or postmenopausal women on HRT [6.00 +/- 0.15, 5.36 +/- 0.17 (P < 0.01), 5.63 +/- 0.13 (P < 0.05) mmol/l, respectively for total cholesterol; 4.13 +/- 0.15, 3.64 +/- 0.15 (P < 0.05), 3.82 +/- 0.12 (P < 0.05) mmol/l, respectively for LDL-cholesterol; 48.19 +/- 9.90, 26.59 +/- 5.53 (P < 0.03), 25.12 +/- 4.62 (P < 0.03) mg/dl, respectively for Lp[a]]. The differences in LDL cholesterol concentrations were inversely related to changes in LDL receptor activity (r = -0.27, P < 0.01). HRT use was found to be associated with a significantly smaller LDL particle size. Plasma triglyceride was significantly higher in women on HRT (1.16 +/- 0.07 mmol/l) than in the premenopausal group (0.96 +/- 0.07) or postmenopausal group not using HRT (0.87 +/- 0.06). There were no differences in LDL oxidation between the groups when LDL was oxidised in the presence of copper. Nor was there any difference in the uptake of copper-oxidised or macrophage-modified LDL into J774 macrophages. These results confirm the effect of menopause and exogenous hormones on plasma lipids and lipoproteins, and suggest that HRT modifies the activity of the LDL receptor. Hormone replacement did not appear to protect LDL from oxidation.

Body fat distribution is a determinant of the high-density lipoprotein response to dietary fat and cholesterol in women

We have conducted a dietary trial that addressed the factors influencing the variability in plasma lipids in response to dietary fat and cholesterol with a focus on the effects of gender and body fat distribution. Sixty-seven women and 53 men were selected so that overall men and women had a similar mean age, LDL cholesterol, and body mass index. After a 2-week low-fat period subjects were given two liquid supplements for 3 weeks each, one that contained 31 to 40 g fat and 650 to 845 mg cholesterol, and one that was fat free. Measurements included plasma lipids and lipoproteins, glucose, insulin, hepatic triglyceride lipase activity, apolipoprotein E polymorphism, and three indexes of body fat (body mass index, waist girth, and waist-hip ratio). In response to dietary fat and cholesterol supplementation only the changes in HDL cholesterol, especially in HDL2, differed between the sexes. Although on univariate analysis lipoprotein changes were predicted by baseline lipoprotein levels, body mass index, waist girth, waist-hip ratio, hepatic triglyceride lipase activity, and insulin, multiple regression showed only waist-hip ratio to predict changes in HDL2 cholesterol in women and body mass index and baseline HDL2 cholesterol in men. Changes in LDL were predicted by baseline LDL cholesterol in women and apolipoprotein E phenotype and age in men. These studies explain much of the variability that individuals show in lipoprotein changes, especially in the more desirable changes in cholesterol transport in HDL2, in response to eating saturated fat and cholesterol.