ApoE polymorphism in a small Mediterranean island: relationships with plasma lipids, lipoproteins and LDL particle size

APOE polymorphism is associated with blood lipid and serum uric acid metabolism in hypertension or coronary heart disease in a Chinese population

Aim: To explore the association of APOE polymorphism (rs7412:526C>T and rs429358:388T>C) with glucose, lipid and serum uric acid (UA) metabolism in patients with hypertension or coronary heart disease (CHD). Methods: A total of 544 patients with hypertension or CHD were selected for this study from March 2017 to January 2018. According to the APOE genotypes (excluding the E2/E4 genotype), the subjects were divided into three groups (E2/E2+E2/E3 genotypes, E3/E3 genotype [the wild-type] and E3/E4+E4/E4 genotypes) and the difference of metabolism among the three groups was compared. Results: There were significant differences in total cholesterol (TC), triglycerides, low-density lipoprotein (LDL), high-density lipoprotein and serum UA levels among the three groups. Compared with APOE E3 homozygote, APOE E4 carriers possessed higher TC, triglycerides and LDL levels, whereas APOE E2 carriers had higher high-density lipoprotein level, lower TC and LDL levels. Furthermore, multivariate logistic regression analysis found that setting E3/E3 genotype as the reference group, the carriers of APOE E4 allele (E3/E4+E4/E4 genotypes) were significantly related to hypertriglyceridemia, and APOE E2 allele (E2/E2+E2/E3 genotypes) was significantly correlated with hyperuricemia. Conclusion: APOE polymorphism was associated with blood lipid and serum UA metabolism in patients with hypertension or CHD. Compared with APOE E3 homozygote, APOE E4 allele was related to elevated triglycerides, and APOE E2 allele was correlated with increased serum UA level.

Relationship Between the Apolipoprotein E Genotype and LDL Particle Size in Patients With Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with dyslipidemia and increased cardiovascular risk. We assessed the effects of apolipoprotein E ( APOE) genotype on low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle size and lipid subclasses (separated by gradient gel electrophoresis) in patients with OSA. Stable patients (n = 181) prospectively recruited underwent full polysomnography. Both LDL particle size and LDL I proportion were reduced from ∊3∊3 homozygotes to ∊2 carriers and to ∊4 carriers (analysis of variance: P = .024; P = .040, respectively); carriers of the ∊4 allele of the APOE genotype had significantly lower LDL particle size and LDL I proportion compared to ∊3∊3 homozygotes ( P < .05 for both comparisons). Insulin resistance increased from patients with no OSA to those with mild–moderate and to those with severe OSA ( P < .001). In multivariate analysis, LDL size was independently predicted by APOE genotype, male gender, and the presence of metabolic syndrome (MetS; P = .001, P = .020, P = .027, respectively). The HDL particle size was not affected by APOE genotype. Our data demonstrate that both the ∊4 APOE genotype and MetS are independently related to smaller LDL size in patients with OSA.

No change of the lipid profile under the control of ApoE gene polymorphism in schizophrenics under paliperidone treatment

The present study tried to explore the effects of Paliperidone on the lipid profiles of schizophrenia patients. One hundred twenty-nine subjects diagnosed with schizophrenia were enrolled into this study and completed the lipid profile evaluation. Their blood samples were obtained on the morning following a 12-hours fast. Cholesterol and triglyceride (TG) levels in plasma were determined, and lipoproteins were determined by enzymatic methods. All participants provided written informed consent, and underwent additional venous blood withdrawal for DNA extraction for genetic study of the ApoE gene polymorphism. Under T test, TC, TG and HDL levels all declined after Paliperidone treatment although with no statistically significant difference. The ratios of TC/HDL declined after Paliperidone treatment, but without statistically significant difference. After GEE-I analysis, we found that ApoE4 genotype (β = 34.471; p < 0.001) had a positive effect on the total cholesterol (TC) level; female had positive effect on the high-density lipoprotein (HDL) level (β = 15.361; p = 0.003); and age had a positive effect on the TG level (β = 1.317; p = 0.030). Smoking (β = 0.961; p = 0.016) had a positive effect on the ratio of TC/HDL change. Lipid profiles were not increased after Paliperidone treatment under the control of ApoE gene polymorphism.

New insights into the distribution of APOE polymorphism in the Iberian Peninsula. The case of Andalusia (Spain)

BACKGROUND

The APOE gene has received much attention due to the remarkable spatial variation patterns of some of its genotypes and alleles in human populations and to its relevance in biomedicine.

AIM

This work was addressed to investigate the extent of APOE polymorphism between autochthonous Andalusians originating from Huelva and Granada provinces. No data on this marker in these southern Spanish coastal populations are available up to date.

SUBJECTS AND METHODS

This study used genomic DNA from healthy, unrelated Andalusians of both sexes (n = 322). All samples were genotyped for two SNPs, rs429358 and rs7412, which determine the three APOE alleles: ε2, ε3 and ε4. For analyses, a TaqMan-based technique was applied using a RT-PCR. Comparisons with other Mediterranean populations were performed based on multivariate analysis.

RESULTS

A relatively high frequency of ε4 in Granada (eastern Andalusia), as well as a low ε2 frequency in Huelva (western Andalusia) were observed. The finding that ε4 allele in Southern Spain and Portugal is higher than expected given its geographical location poses an interesting question for this study, given the well-established APOE-ε4 gradient in Europe.

CONCLUSION

This population study may represent useful information for further prospective anthropological and molecular genetic studies focused on unravelling the relationship between population genetic composition and specific human diseases.

Impact of APOE gene polymorphisms on the lipid profile in an Algerian population

Background

The importance of apolipoprotein E (APOE) in lipid and lipoprotein metabolism is well established. However, the impact of APOE polymorphisms has never been investigated in an Algerian population. This study assessed, for the fist time, the relationships between three APOE polymorphisms (epsilon, rs439401, rs4420638) and plasma lipid concentrations in a general population sample from Algeria.

Methods

The association analysis was performed in the ISOR study, a representative sample of the population living in Oran (787 subjects aged between 30 and 64). Polymorphisms were considered both individually and as haplotypes.

Results

In the ISOR sample, APOE ϵ4 allele carriers had higher plasma triglyceride (p=0.0002), total cholesterol (p=0.009) and LDL-cholesterol (p=0.003) levels than ϵ3 allele carriers. No significant associations were detected for the rs4420638 and rs439401 SNPs. Linkage disequilibrium and haplotype analyses confirmed the respectively deleterious and protective impacts of the ϵ4 and ϵ2 alleles on LDL-cholesterol levels and showed that the G allele of the rs4420638 polymorphism may exert a protective effect on LDL-cholesterol levels in subjects bearing the APOE epsilon 4 allele.

Conclusion

Our results showed that (i) the APOE epsilon polymorphism has the expected impact on the plasma lipid profile and (ii) the rs4420638 G allele may counterbalance the deleterious effect of the ϵ4 allele on LDL-cholesterol levels in an Algerian population.

Oxidative stress and small, dense low-density lipoproteins: current and future perspectives

Small, dense low-density lipoproteins (LDLs) are more susceptible to oxidation than their larger, more buoyant counterparts and therefore the biological modification of these LDL particles may, in part, be responsible for their atherogenic properties. Kotani et al. found that at multiple regression analysis there was an independent and significant inverse correlation between the mean LDL particle size and the oxidative stress status; notably, the authors adjusted not only for the traditional cardiovascular risk factors, but also for drug treatments. Higher levels of small, dense LDL concentrations significantly contribute to atherosclerosis, and lipoprotein size and subfractions may refine cardiovascular disease risk assessment.

Apolipoprotein E genotype and mortality in Southern European and Anglo-Celt patients with type 2 diabetes: the Fremantle Diabetes Study

OBJECTIVE

To determine whether cardiac and all-cause mortality are lower in Southern European (SE) patients than in Anglo-Celt (AC) patients with type 2 diabetes in an urban Australian setting, and, if so, whether ethnicity-specific differences in apolipoprotein E (APOE) genotypes are contributory.

DESIGN

Longitudinal observational cohort study.

METHODS

We analysed detailed data from 1057 patients from the community-based Fremantle Diabetes Study, 238 were of an SE migrant background and 819 of AC ethnicity. Cox proportional hazards modelling was used to identify independent predictors of cardiac and all-cause mortality.

RESULTS

During 9.8±3.5 years of follow-up, 411 (38.9%) participants died, 161 (39.2%) from cardiac causes. Significant positive baseline independent predictors of cardiac death were age, male gender, coronary heart disease, cerebrovascular disease, peripheral arterial disease, retinopathy and peripheral neuropathy (P≤0.004), while maternal history of diabetes was protective (P=0.014). After adjusting for these variables, APOE4 carriage was predictive (hazard ratio (95% confidence interval) 1.61 (1.01-2.58); P=0.048). SE ethnicity did not add significantly to the model either as a single variable or as an interaction term with APOE4 carriage (P≥0.86). Significant independent predictors of all-cause mortality were age, male gender, smoking, coronary heart disease, cerebrovascular disease, peripheral arterial disease, retinopathy, peripheral neuropathy and microalbuminuria (P≤0.047), while overweight/obesity, lipid-lowering therapy and recent exercise were protective (P≤0.008). APOE4 carriage, SE ethnicity and their interaction did not add to the model (P≥0.32).

CONCLUSIONS

SE ethnicity does not confer an independent survival advantage in community-based Australian type 2 diabetic patients, but APOE4 carriers are at higher risk of cardiac death.

Comparative study of apolipoprotein-E polymorphism and plasma lipid levels in dyslipidemic and asymptomatic subjects, and their implication in cardio/cerebro-vascular disorders

Polymorphisms in the apolipoprotein-E (apoE) gene may modulate lipoprotein metabolism at different steps and influence total and low density lipoprotein (LDL) cholesterol (LDLc) levels, as well as other lipid features. Population studies have documented significant differences in the frequency of apoE alleles which are related to the prevalence of various cardio-vascular and neuro-psychiatric diseases. In this study, the apoE genotypes and allele frequencies were analyzed in 216 individuals (109 dyslipidemic and 107 normo-lipidic subjects), and the relative contribution of apoE polymorphism on plasma lipid and lipoprotein levels, as well as risk factors was evaluated. In normo-lipidic volunteers, the frequencies of epsilon2, epsilon3 and epsilon4 alleles were 0.042, 0.832 and 0.126, while in dyslipidemic subjects 0.046, 0.835 and 0.119, respectively. No significant difference was observed among epsilon2, epsilon3 or epsilon4 and plasma lipid-lipoprotein levels in the dyslipidemic group. In normo-lipidemics, however, total cholesterol, LDLc and non-HDLc plasma levels were significantly lower in epsilon2 subjects when compared to epsilon3 and epsilon4 individuals. The allelic frequencies of apoE epsilon2, epsilon3 and epsilon4 were similar in dyslipidemic and normo-lipemic subjects, suggesting that apoE polymorphisms have no effect on plasma lipid-lipoprotein levels in dyslipidemic subjects. In contrast, in normo-lipemic subjects the epsilon2 allele showed to be associated with lower total cholesterol and LDLc levels, the mark of a better lipid profile. Depending on other co-existing factors, the epsilon2 allele, therefore, may play either a protective or pathogenic role. This elementary knowledge is a fundamental prerequisite for a possible diagnostic application of these lipoproteins as biomarkers to predict adverse cardio-vascular and/or neuro-psychiatric maladies.

Gender-related effect of apo E polymorphism on lipoprotein particle sizes in the middle-aged subjects

OBJECTIVES

We determined the frequencies of apolipoprotein E (apo E) alleles and examined the effect of apo E polymorphism on lipoprotein particle sizes in Serbian healthy, middle-aged individuals.

DESIGN AND METHODS

We performed apo E phenotype by immunobloting method in 183 men and 143 women (mean years: 56.3+/-10.60 and 54.9+/-10.31, respectively). Plasma lipid and apolipoprotein levels were measured by routine laboratory methods. LDL and HDL particle sizes were determined by nondenaturing polyacrylamide gradient (3-31%) gel electrophoresis.

RESULTS

The apo E allele frequencies were epsilon2--4.9%, epsilon3--86.5%, and epsilon4--8.6%. Men with epsilon4 allele had lower HDL-C and Apo AI concentrations than epsilon3 men. The epsilon2 allele men had the smallest LDL particles, highest percent of subjects with LDL phenotype B and highest TG/HDL-C ratio. Women with epsilon2 allele had lowest concentration of apo B. The epsilon4 allele women had smallest HDL particles and highest percent of the subjects with small-sized HDL phenotype.

CONCLUSIONS

This study showed gender-related effect of apo E polymorphism on lipoprotein particle size. In men, possession of the epsilon2 allele is associated with small LDL particles, whereas in women, epsilon4 allele is associated with small HDL particles. Differences in gender-related influence of apo E polymorphism on LDL and HDL particle sizes could be clinically useful in strategy for reduction of coronary disease risk in middle-aged men and women.

Apolipoprotein E Genotypic Frequencies Among Down Syndrome Patients Imply Early Unsuccessful Aging for ApoE4 Carriers

Down syndrome (DS) might be considered a model for unsuccessful and early aging, possibly accelerated for those who carry the APOE4 allele associated with common age-related diseases, e.g., Alzheimer's disease and a poor prognosis after acute myocardial infarction, causing lower ApoE4 frequencies among the very old in general populations. We compared ApoE genotypic frequencies found for healthy adults (n = 211, age < 40; n = 79, ages 70-79; n = 71, ages > 90) to those found for DS patients (n = 106, mean age 9 years), all living in western Sicily. We found that the frequency of the ApoE23 genotype increased with age among the healthy adults (8.5%, 6.4%, 19.7%; p = 0.024) while ApoE34 frequency decreased (16.1%, 12.6%, 4.1%; p = 0.012). DS patients had APOE34 genotypic frequencies very similar to those found in septuagenarians (9%; p = 0.005). Analyzing results according to surviving rate of persons with DS, an age-related reduction of ApoE3/4 genotype frequency was found comparing =5 years old to >5 years old DS subjects. These results highlight DS as a model to understand the role of APOE4 allele in unsuccessful ageing considering that a number of proinflammatory supernumerary genes (Cu/Zn superoxide dismutase, Ets-2 transcription factors, Down syndrome critical region 1, stress-inducible factor, interferon-alpha receptor and the amyloid precursor protein) are located on chromosome 21 and are implied in the pathologic processes of DS.

Ethnicity may be a reason for lipid changes and high Lp(a) levels in rheumatoid arthritis

There are so many studies that suggest the changes in lipid profiles and lipoprotein (a) [Lp(a)] are associated with early atherosclerosis in rheumatoid arthritis (RA). But there are some opposite studies also. Because of marked ethnicity differences in the distribution of Lp(a), we aimed to investigate the associations of Lp(a) levels and lipid changes in Turkish RA patients. There were 30 women and 20 men, a total of 50 patients with RA (mean age 47.6 +/- 13.2 years), included and 21 healthy women and 14 healthy men (mean age 45.7 +/- 14.5 years) were recruited as a control (C) group. Serum Lp(a), total cholesterol (TC), triglyceride (TG), HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) levels were analysed for each group. Analysis of six different studies was performed. In the RA and C groups, mean serum Lp(a) levels were 39.7 +/- 64.4 and 10.5 +/- 13.4 mg/dl, respectively (P=0.001). Mean TC levels were 189.2 +/- 142.5 and 174.0 +/- 29.3 mg/dl (P=0.294), mean TG levels were 121.4 +/- 65.4 and 106.5 +/- 80.0 mg/dl (P=0.030), mean HDL-C levels were 44.5 +/- 10.0 and 47.7 +/- 4.8 mg/dl (P=0.014) and mean LDL-C levels were 94.3 +/- 35.3 and 102.0 +/- 24.6 mg/dl (P=0.98), respectively. Analysis of the six studies showed Lp(a) level was higher and HDL level was lower in RA patients than in healthy controls. Patients with RA may have altered lipid profiles from one country to another one. Especially in Turkey, higher serum Lp(a), lower HDL-C and higher TG levels may be found in RA patients instead of some findings of other countries showing different results. Ethnicity may be a reason for these findings.

A Module Map Showing Interaction between Apolipoprotein E and Phospholipase A2 Polymorphism in Lipid Profiles

OBJECTIVE

Establish a possible conceptual relationship among Apo E and PLA2 polymorphism and lipid profiles.

METHODS

Five hundred subjects aged 65 to 74 years were randomly selected from a community in southern Taiwan to assess the relationship between Apo E and PLA2 polymorphisms and lipid profiles. Two hundred fifty-six participants agreed to have venous blood drawn for DNA studies.

RESULTS

By multiple linear regression, the PLA2 A2 allele showed a statistically significant influence on LDL-C (p = 0.0097), and the Apo epsilon2 allele showed a statistically significant influence on HDL-C (p = 0.0004), however, the interaction between the PLA2 A2 allele and the Apo epsilon2 allele was found to be significant in the blood fraction of HDL-C (p = 0.0388) and LDL-C (p = 0.0002). Decreasing HDL-C and increasing LDL-C were found when the PLA2 A2 and Apo epsilon2 allele co-existed.

CONCLUSION

The presence of a physiologic balance contributes significantly to homeostatic and compensatory responses regulating blood HDL-C and LDL-C profiles. A module map of the generation-control cycle and conditional activity among Apo E, PLA2, and lipid levels is presented, and both behaviours and biological perspectives under the consilience model may suggest a new approach to many kinds of complex disorders.

Allele ɛ4 of APOE is a stronger predictor of Alzheimer risk in Sicily than in continental South Italy

The genotype of apolipoprotein E was examined in 173 sporadic Alzheimer's disease (AD) patients, 132 with late onset (LOAD) and 41 with early onset (EOAD), and in 174 healthy matched controls from Sicily. Despite a low frequency of the epsilon 4 allele (6.3%, 95% CI: 4.2--9.4) in controls, epsilon 4 allele was a stronger predictor of AD risk (odds ratio: 5.8, 95% CI: 3.5--9.4; p<0.0001) than in most of the studies performed in other regions of Italy, and it has no influence on age at onset. epsilon 4/epsilon 4 and epsilon 4/epsilon 3 genotypes were similar predictors of AD risk. Conversely, a decreased risk was found in epsilon 3 allele carriers (odds ratio: 0.3, 95% CI: 0.2--0.4; p<0.0001), which remained significant when considering EOAD cases only (odds ratio: 0.2, 95% CI: 0.1--0.4, p<0.0001). In conclusion, differences in association strength of epsilon 4 allele with AD between Sicily and other regions of Italy suggest an influence of complex gene-gene and gene-environment interactions.

The effect of dietary fat on LDL size is influenced by apolipoprotein E genotype in healthy subjects

LDL particle size is dependent on both genetic factors and environmental factors such as dietary fat composition. The apolipoprotein E (apoE) genotype is a major genetic determinant of LDL size. Thus, the aim of this work was to study whether the apoE genotype interacts with the quantity and quality of dietary fat, modifying LDL size in young healthy subjects. Healthy subjects (n = 84; 66 apoE 3/3, 8 apoE 4/3, 10 apoE 3/2) were subjected to 3 dietary periods, each lasting 4 wk. The first was an SFA-enriched diet (38% fat, 20% SFA), which was followed by a carbohydrate (CHO)-rich diet (30% fat, < 10% SFA, 55% carbohydrate) or a monounsaturated fatty acid (MUFA) olive oil-rich diet (38% fat, 22% MUFA) following a randomized crossover design. At the end of each diet period, LDL particle size and plasma levels of total cholesterol, LDL cholesterol (LDL-C), HDL-C, apoB, apoA-I, and triacylglycerols were determined. LDL particle size was significantly higher (P < 0.04) in subjects with the apoE 4/3 genotype compared with those with apoE 3/3 and apoE 3/2 in the basal state. LDL size was smaller (P < 0.02) after the CHO diet than after the MUFA or SFA diets. After the CHO diet, a significant increase in LDL particle size (P < 0.035) was noted with respect to the MUFA diet in apoE 4/3 subjects, whereas a significant decrease was observed in the apoE 3/3 individuals (P < 0.043). In conclusion, a Mediterranean diet, high in MUFA-fat increases LDL particle size compared with a CHO diet, and this effect is dependent of apoE genotypes.

Genetics of LDL particle heterogeneity

Substantial evidence exists suggesting that small, dense LDL particles are associated with an increased risk of coronary heart disease. This disease-related risk factor is recognized to be under both genetic and environmental influences. Several studies have been conducted to elucidate the genetic architecture underlying this trait, and a review of this literature seems timely. The methods and strategies used to determine its genetic component and to identify the genes have greatly changed throughout the years owing to the progress made in genetic epidemiology and the influence of the Human Genome Project. Heritability studies, complex segregation analyses, candidate gene linkage and association studies, genome-wide linkage scans, and animal models are all part of the arsenal to determine the susceptibility genes. The compilation of these studies clearly revealed the complex genetic nature of LDL particles. This work is an attempt to summarize the growing evidence of genetic control on LDL particle heterogeneity with the aim of providing a concise overview in one read.

Association between HFE mutations and acute myocardial infarction: a study in patients from Northern and Southern Italy

There is interest in the role of iron in age-related diseases such as atherosclerosis. Tissue iron deposition could be harmful, because Fe(2+) can react with H(2)O(2) to form OH(-) radicals and Fe(2+) can react with O(2) to form reactive oxygen species. Free radicals react with cell membranes and cell organelles and could lead to the development of atherosclerosis by initiating lipid peroxidation. Hereditary hemochromatosis provides an opportunity for studying the effects of iron on cardiovascular disease. Some studies have shown that individuals who carried HFE mutations may be at greater risk of developing coronary heart disease than those without the mutations. In contrast, a large number of studies have reported no association between HFE mutations and coronary heart disease. These studies have possible confounding factors, such as the homogeneity of the population in term of geographical origin among others. We studied the relation between HFE mutations and acute myocardial infarction in two case-control studies involving two sets of subjects representing different age groups from different geographic regions in Italy. The first one was composed of 172 older patients (139 males and 33 females; mean age 67) and 207 healthy controls (91 males and 116 females; mean age 46) from Emilia-Romagna. The second one was composed of younger 77 patients (75 males and 2 females; mean age 41) and 172 healthy controls (75 males and 97 females, mean age: 38) from Sicily. All patients were genotyped for ApoE alleles, since the ApoE- epsilon 4 allele is considered a risk factor for cardiovascular diseases and can interfere with other genetic and environmental factors by modifying susceptibility to this disease. DNA typing for C282Y and H63D HFE alleles was performed also. There were no significant differences in frequencies of the different HFE alleles between acute myocardial infarction patients and controls in cohorts of both old and young patients. Also taking into account the presence or absence of the ApoE- epsilon 4 allele, no significant differences in H63D allele frequencies were observed. Thus, our study, performed in two samples of genetically homogeneous patients and controls, does not support the suggestion that HFE mutations may be associated with acute myocardial infarction in susceptible individuals.

Evidence for a major quantitative trait locus on chromosome 17q21 affecting low-density lipoprotein peak particle diameter

BACKGROUND

Several lines of evidence suggest that small dense LDL particles are associated with the risk of coronary heart disease. Heritability and segregation studies suggest that LDL particle size is characterized by a large genetic contribution and the presence of a putative major genetic locus. However, association and linkage analyses have thus far been inconclusive in identifying the underlying gene(s).

METHODS AND RESULTS

An autosomal genome-wide scan for LDL peak particle diameter (LDL-PPD) was performed in the Québec Family Study. A total of 442 markers were genotyped, with an average intermarker distance of 7.2 cM. LDL-PPD was measured by gradient gel electrophoresis in 681 subjects from 236 nuclear families. Linkage was tested by both sib-pair-based and variance components-based linkage methods. The strongest evidence of linkage was found on chromosome 17q21.33 at marker D17S1301, with an LOD score of 6.76 by the variance-components method for the phenotype adjusted for age, body mass index, and triglyceride levels. Similar results were obtained with the sib-pair method (P<0.0001). Other chromosomal regions harboring markers with highly suggestive evidence of linkage (P< or =0.0023; LOD > or =1.75) include 1p31, 2q33.2, 4p15.2, 5q12.3, and 14q31. Several candidate genes are localized under the peak linkages, including apolipoprotein H on chromosome 17q, the apolipoprotein E receptor 2, and members of the phospholipase A2 family on chromosome 1p as well as HMG-CoA reductase on chromosome 5q.

CONCLUSIONS

This genome-wide scan for LDL-PPD indicates the presence of a major quantitative trait locus located on chromosome 17q and others interesting loci influencing the phenotype.

Low-density-lipoprotein peak particle size in a Mediterranean population

BACKGROUND

The predominance of small, dense low-density lipoprotein (LDL) particles ('LDL phenotype B') has been associated with a three-fold increased risk of myocardial infarction, but the feasibility of the identification of small, dense LDL as independent predictors of coronary artery disease risk in population studies remains questioned. Design We evaluated the LDL peak particle size and its relation with other established risk factors for coronary heart disease in a group of 156 randomized subjects living on the Mediterranean island of Ustica (71 males and 85 women, range of age 20-69 years), representing approximately 30% of the total population.

RESULTS

The prevalence of LDL phenotype B subjects was low (approximately 15% in both men and women) and there was a clear trend for both genders in reducing the LDL peak particle size with age. Moreover, LDL phenotype B subjects had higher BMI values, prevalence of diabetes and plasma triglyceride (TG) levels and lower plasma HDL-C concentrations in comparison with LDL phenotype A individuals; in a multivariate analysis, plasma TG levels were the only variable independently associated with LDL peak particle size.

CONCLUSIONS

In this population, which appears to be somewhat protected by premature coronary artery disease, a low prevalence of the LDL pattern B was found in both men and women, and plasma TG could have a key role in regulating the LDL peak particle size. The follow up, still ongoing, will provide useful information on the predictive role of LDL peak particle size on cardiovascular risk, at least in a low-risk population.