Lipoprotein and apolipoprotein levels among Mexican-Americans in Starr County, Texas

Impaired anti-inflammatory function of apolipoprotein A-II concentrations predicts metabolic syndrome and diabetes at 4 years follow-up in elderly Turks

BACKGROUND

We evaluated prospectively the predictive value of serum apolipoprotein (apo) A-II, the second major apolipoprotein of high-density lipoprotein (HDL), for cardiometabolic risk in Turkish adults showing abnormalities in other proteins that normally confer protection.

METHODS

Determinants of apoA-II and its associations with coronary heart disease (CHD), metabolic syndrome (MetS) and diabetes were investigated at 4 years follow-up in 193 elderly men and women.

RESULTS

ApoA-II concentrations at baseline, in addition to being significantly related to HDL-cholesterol, were directly associated with complement C3 in multivariate linear regression analyses comprising nine variables. Following adjustment for gender, age and HDL-cholesterol (>30/>33 g/L, in men and women, respectively), low serum apoA-II concentrations predicted incident MetS [relative risk (RR) 3.5 (95% CI 1.4; 8.6)] and type 2 diabetes [RR 4.5 (95% CI 1.3; 15.6)] in both genders at an increment of 1 SD. Increased apoA-II values were not associated with prevalent or incident CHD, and tended to be marginally atheroprotective only in males.

CONCLUSIONS

Serum apoA-II concentrations confer risk for MetS and diabetes and exhibit evidence of anti-inflammatory properties among Turks. These findings support the effects seen for several other HDL protein constituents. This finding may explain the increased cardiometabolic risk among Turks.

Application of national screening criteria for blood pressure and cholesterol to perimenopausal women: prevalence of hypertension and hypercholesterolemia in the Study of Women's Health Across the Nation

National screening guidelines for hypertension and cholesterol were applied to the multiethnic sample of perimenopausal women (N = 1349) in the Study of Women's Health Across the Nation (SWAN). To reduce low-density lipoprotein, lifestyle modification was indicated in 9.5% of patients and drug therapy in 5%. Chinese and Japanese women were least likely and African Americans were most likely to require interventions. Among all women, 27% were prehypertensive, 23% were hypertensive (blood pressure >140/90 mm Hg or treated), and 9.1% were untreated hypertensive. Untreated hypertension was lowest among Japanese and Chinese and highest among Hispanic and African-American women. Among all hypertensives, 60.5% were treated and only 58.5% of those treated were controlled. Control rates were lowest among African Americans and Hispanics. In this relatively low-risk population, a significant proportion of women with hypertension or hypercholesterolemia were either not treated, not treated adequately, or had borderline risk factors that would benefit from lifestyle interventions to prevent the need for future drug treatment.

Plasma lipoprotein concentrations in ethnic populations

There is a complex interplay between genetic and environmental factors that influences the expression of plasma lipoprotein levels. It is therefore not surprising that differences in lipid levels have been reported between ethnic groups. There are conflicting data on racial and ethnic variations in lipids, and also limited data on the relationship between lipoprotein levels and coronary heart disease risk in specific populations. This review summarizes available data on ethnic variations in plasma lipoproteins and the potential impact on coronary morbidity and mortality.

Association Between Serum Concentration of Apolipoproteins A-I and B with Gallbladder Disease

BACKGROUND

A total of 1,255 subjects attending a private health care facility in Mexico City were studied to evaluate the association of serum concentration of Apo A-I and Apo B with presence of gallbladder disease (gallstones or cholecystectomy).

METHODS

A cross-sectional study was carried out. All participants provided data on sociodemographic status and previous diagnoses of type 2 diabetes, hypertension, cardiovascular events, alcohol consumption, and smoking habits. Women additionally reported their obstetric-gynecologic history. Weight and height were measured; liver and biliary tract ultrasound assessed gallbladder disease. Plasma levels of total cholesterol, triglycerides, high-density lipoproteins (HDL) cholesterol, and apolipoproteins A-I (Apo A-I) and B (Apo B) were determined after a 12-h fasting period.

RESULTS

In multivariate models, Apo A-I > or = 120 mg/dL was positively associated with gallbladder disease with odds ratio (OR) = 1.64, 95% confidence interval (95% CI) = 1.03-2.62, whereas Apo B > or = 120 mg/dL showed an inverse association (OR = 0.71, 95% CI = 0.48-1.05). Ratio of Apo B/Apo A-I > or = 1 was inversely associated with risk of gallbladder disease (OR = 0.54, 95% CI = 0.37-0.80). All models were adjusted for age, gender, body mass index (BMI), previous diagnosis of type 2 diabetes, triglycerides, alcohol consumption, tobacco, and contraceptive use, as well as for total cholesterol in HDL-cholesterol and Apo A-I models.

CONCLUSIONS

Our results suggested the relationship between serum concentration of apolipoproteins and gallbladder disease. These findings support the hypothesis of increased biliary catabolism of cholesterol in subjects with gallbladder disease characterized by lower Apo B and higher Apo A-I serum concentrations.

The effects of genotype and infant weight on adult plasma levels of fibrinogen, factor VII, and LDL cholesterol are additive

High circulating levels of cholesterol, particularly low density lipoprotein (LDL) cholesterol and the clotting factors fibrinogen and factor VII, are associated with increased risk of myocardial infarction. Variations in the plasma levels of these factors are determined in part by polymorphisms in the genes concerned and also by weight at 1 year (infant weight). We have looked at the possibility of interactions between these genetic factors and infant weight in a sample of 290 men and 192 women from Hertfordshire using the beta-fibrinogen G/A-455, factor VII R353Q, and ApoE polymorphisms. The rare allele frequencies of the three polymorphisms were 0.19 for beta-fibrinogen, 0.10 for factor VII, and 0.07 and 0.13 for the 2 and 4 alleles of ApoE, and these frequencies were not different in subjects of different infant weight. In this sample, the polymorphisms showed the expected effects on plasma levels of fibrinogen, factor VII, and LDL cholesterol. The A-455 allele was associated with higher fibrinogen levels but the effect was only statistically significant in women (p = 0.003). The R353 allele was associated with higher factor VII activity in both men and women (p < 0.0001 for both). The ApoE2 allele was associated with lower levels of LDL cholesterol (p = 0.03 in men, p = 0.006 in women), while the ApoE4 allele was associated with higher levels (p < 0.001 in men, not significant in women). In this sample of men and women the effect of low infant weight was only associated with significant effects on fibrinogen and LDL cholesterol in the group of men (p = 0.005 and p = 0.008 respectively). Compared with the E3E3 subjects, the LDL lowering effect of the E2 allele and the raising effect of the E4 allele was greater in those with low infant weight compared with those with high infant weight (low v high infant weight for E2: 12.7% v 9.4%; for E4 12.7% v 8.5%). Although in this sample the interactive effect did not reach statistical significance, the additive effect of ApoE genotype and low infant weight on determining plasma LDL cholesterol levels, if confirmed, may be of relevance in determining a person's future risk of atherosclerosis.

Food-frequency questionnaire validation among Mexican-Americans: Starr County, Texas

A food-frequency questionnaire (FFQ) for low-income Mexican-Americans in Starr County, Texas, was developed as part of an epidemiologic study of gallbladder disease during 1985 and 1986. The FFQ was developed from 7-day food records collected from the first sample. In the validity study, using the second sample, correlations between nutrients calculated from 3-day food records and the FFQ were 0.77, 0.76, and 0.61 for energy, total fat, and saturated fat, respectively. In the reliability study, using the third sample, for the 1-month interval between baseline and a repeat FFQ measurement correlations ranged from 0.90 for energy to 0.85 for total fat and for the 2-month interval they were 0.84 for energy and 0.70 for total fat. The high correlations are largely explained by the lack of diversity in the diets of Starr County individuals which facilitated the high agreement between the FFQ and the food records for estimates of energy, fats, and cholesterol.

Lipids, lipoproteins and coronary heart disease in minority populations

Despite recent advances in both prevention and treatment, cardiovascular disease (CVD) remains the leading cause of mortality in the US. The Framingham Study was a landmark in defining CHD-related risk factors; unfortunately, very few minorities were included. A major preventable risk factor for CHD continues to be lipid abnormalities, but its association within minority populations is unclear. The few studies that have examined the association of hyperlipidemia with CHD in minorities have shown that total cholesterol was a predictor of CHD risk (e.g., black men aged 35-64). Several researchers have reported higher levels of HDL for black men and women compared to white men and women. Since HDL was shown to be inversely related to CHD, this discrepancy in HDL is hypothesized to account for the lower than expected mortality rate. Lipoprotein(a) has been identified as an independent risk factor for CHD; blacks have considerably higher levels than whites. Data also indicate the following: Hispanics have lower CVD mortality rates than the general population despite having known risk factors (e.g., obesity, diabetes, low socioeconomic status); Hispanic women have lower levels of HDL cholesterol; Native-American populations have lower prevalence of CHD associated with lower LDL-cholesterol and higher HDL-cholesterol. Understanding epidemiologic and pathophysiologic data regarding differences between various racial groups should help reduce CVD-related morbidity and mortality in minority populations.

Juxtaposed short sequence repeat types and haplotypes near exon 3 of the insulin receptor locus among Mexican Americans

The insulin receptor has been sequenced on numerous occasions and reports suggest several potential polymorphisms, as do a number of reports of single base changes. Examining these reports identifies five potential polymorphisms at or near exon 3. Three of these--codon 233 (CTG to CCG), codon 234 (GAC to GAT), and codon 276 (CAG to CAA)--predict restriction site differences. Just 5' of exon 3, the sequence suggests the presence of two short sequence repeats (SSRs), one with ATTT repeats and one with TC dinucleotide repeats. Amplification of exon 3 using the polymerase chain reaction followed by appropriate restriction digestion demonstrated no variation in a sample of 50 Mexican Americans. The codon 276 results were surprising given several reports showing the putative differences. An additional 91 mixed samples were examined and no variation was detected, suggesting that the reported differences likely resulted from sequencing artifacts. Amplification of a smaller fragment demonstrated 10 phenotypes and 7 alleles for the SSR region. Digestion with MnlI permitted scoring each motif separately and when coupled with the uncut results permits unequivocal classification of haplotypes without familial data. These juxtaposed SSRs should be useful for linkage analysis and investigations of gene structure and evolution.

Effects of the apolipoprotein E polymorphism on levels of lipids, lipoproteins, and apolipoproteins among Mexican-Americans in Starr County, Texas

Genetic variability has been implicated as a significant contributor to the variation in levels of lipids, lipoproteins, and apolipoproteins (apos) through a variety of direct and indirect investigations. Among the direct investigations, apo E has been shown to be polymorphic and to explain a small but statistically significant proportion of the variability in cholesterol. The apo E polymorphism was typed in 964 randomly selected Mexican-Americans from Starr County, Tex., and its effects determined on levels of cholesterol, triglycerides, total high density lipoprotein (HDL) cholesterol, subfractions (HDL2 and HDL3), alpha- and beta-lipoprotein cholesterol, low density lipoprotein (LDL) cholesterol, and apos A-I, A-II, B, C-II, C-III, and E. Effects are reported for the entire sample and in each of three groups, namely, premenopausal females, postmenopausal women, and males. In the entire sample, significant effects were observed on cholesterol, beta-lipoprotein cholesterol, LDL, apo B, and apo E. There is evidence for significant physiological interaction of the apo E polymorphism effect in females by menopausal status. This is most evident for apo E levels, in which 5.9% of the variability in the entire sample is explained by the apo E polymorphism. In premenopausal females, however, the polymorphism accounts for 27.5% of the variability. In postmenopausal women and males, there is no significant effect. It is shown that the apo E polymorphism can be treated as a two-locus, two-allele system. Doing so identifies substitutions in amino acid position 158 as the mediators of most of the observed effects of this polymorphism.