Apolipoprotein E polymorphisms and mortality in Italian type 2 diabetic patients

Role of the APOE polymorphism in carotid and lower limb revascularization: A prospective study from Southern Italy

BACKGROUND

Atherosclerosis is a complex multifactorial disease and the apolipoprotein E (APOE) polymorphism has been associated to vascular complications of atherosclerosis.

OBJECTIVES

To investigate the relationship between the APOE genotypes and advanced peripheral vascular disease.

MATERIALS AND METHODS

258 consecutive patients (201 males and 57 females, mean age 70.83 ± 7.89 years) with severe PVD were enrolled in a 42-months longitudinal study (mean 31.65 ± 21.11 months) for major adverse cardiovascular events. At follow-up genotypes of the APOE polymorphism were investigated in blinded fashion.

RESULTS

As compared with ε3/ε3, in ε4-carriers a significant higher incidence of major adverse cardiovascular events (35.58% vs. 20.79%; p = 0.025) and total peripheral revascularization (22.64% vs. 5.06%; p < 0.001) was observed. Prospective analysis, showed that ε4-carriers have an increased hazard ratio for major adverse cardiovascular events (adjusted HR 1.829, 95% CI 1.017-3.287; p = 0.044) and total peripheral revascularization (adjusted HR = 5.916, 95% CI 2.405-14.554, p <0.001).

CONCLUSIONS

The ε4 allele seems to be risk factor for major adverse cardiovascular events, and in particular for total peripheral revascularization in patients with advanced atherosclerotic vascular disease.

Apolipoprotein E ε4 allele interacts with sex and cognitive status to influence all-cause and cause-specific mortality in U.S. older adults

OBJECTIVES

To confirm associations of apolipoprotein E (ApoE) ε4 carrier status, sex, and time-dependent cognitive status with mortality risk and to investigate these joint effects of these associations in a cohort of community-dwelling U.S. adults.

DESIGN

Prospective cohort study.

SETTING

The Baltimore Longitudinal Study of Aging (BLSA).

PARTICIPANTS

Of 3,047 BLSA participants aged 17 to 98 at first visit (60.1% male), 1,704 with complete ApoE genotype data were included, of whom 1,461 aged 50 and older with one or more visits were eligible.

MEASUREMENTS

Time to death from all, cardiovascular, and noncardiovascular causes.

RESULTS

Probability of survival was lower for ApoE ε4 carriers, particularly those who were older. A Cox proportional hazards model for all-cause mortality yielded a hazard ratio (HR) for ApoE ε4 carrier versus noncarriers of 1.31 (95% confidence interval (CI) = 1.02-1.68). This association was also found for cardiovascular mortality. Time-dependent all-cause dementia (HR = 1.73, 95% CI = 1.33-2.26) and mild cognitive impairment (HR = 1.95, 95% CI = 1.42-2.67) increased all-cause mortality risk, associations that were also detected for noncardiovascular mortality. When individuals were free of cognitive impairment, a dose-response relationship with ε4 alleles was found for all-cause mortality (HR = 1.40, 95% CI = 0.94-2.07 for 1 ε4; HR = 2.61, 95% CI = 1.12-6.07 for 2 ε4). After onset of Alzheimer's disease (AD), carrying only one ε4 allele resulted in an approximately 77% greater all-cause mortality risk than in noncarriers. ApoE ε4 carrier status increased all-cause mortality risk in men and interacted with time-dependent AD to increase the risk of this outcome (relative excess risk due to interaction = 2.15, 95% CI = 1.22-3.07).

CONCLUSION

ApoE ε4 carrier status was found to increase all-cause and cardiovascular mortality risks and interacted with sex and time-dependent AD status to affect all-cause mortality.

Apolipoprotein E gene polymorphism and its effect on anthropometric measures in normoglycemic subjects and type 2 diabetes

Background

Apolipoprotein E (apo E) plays a major role in lipid metabolism, obesity and accordingly in development of diabetes and coronary heart disease (CHD). Our main objective was to evaluate the association between apo E gene polymorphism with anthropometric measures.

Methods

Participants were selected from zone 17 Tehran/Iran. We assessed height, weight, body mass index (BMI), waist circumference (WC), blood pressure, serum fasting blood sugar, total cholesterol and triglycerides. Genotyping for apo E gene polymorphism was carried out using PCR-RFLP technique.

Results

Among total study population (n=311), 156 subjects were diabetic. The apo E3/E3 was the most common genotype in our population while E2 and E4 alleles had lower frequencies, respectively. After adjustment for diabetes, the apo E2 and E4 alleles were significantly associated with hypercholesterolemia and WC, respectively (p= 0.009, 0.034). This association was also related to sex and age. The probability of having abdominal obesity in E4 allele carriers was increased from 0.22 to 8.12 in women and to 3.08 in age ≥ 50 years.

Conclusions

Apo E polymorphism had significant influences on WC and total cholesterol level in patients with type 2 diabetes. This study highlights the importance of lifestyle modifications which may be more beneficial in hypercholesterolemic women carriers of E2 and E4 alleles concomitant central obesity.

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.

Association between apolipoprotein E polymorphism, lipids, and coronary artery disease in Tunisian type 2 diabetes

BACKGROUND

The relationship between apolipoprotein E (ApoE) polymorphism, fasting lipid parameters, and coronary artery disease (CAD) is controversial.

METHODS

We studied this relationship, for the first time, in Tunisian type 2 diabetic patients. The studied population comprised 157 type 2 diabetic patients (145 of them were not on any lipid-lowering drugs). Fasting lipids were measured by enzymatic methods and ApoE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Our results showed that the alleles E2, E3, and E4 were found in 4%, 88%, and 8% of patients, respectively. In the total type 2 diabetic population, no association was found between ApoE polymorphism, lipid parameters, and CAD. However, the E4 allele was associated with elevated low-density lipoprotein cholesterol concentration and with CAD in type 2 diabetic men.

CONCLUSION

The effect of ApoE polymorphism on CAD is gender-dependent in the Tunisian type 2 diabetic population. ApoE 4 allele may enhance atherogenesis indirectly by a strong effect on low-density lipoprotein cholesterol.

Apolipoprotein E genotype and plasma lipid levels in Caucasian diabetic patients

OBJECTIVE

Apo E polymorphism has been shown to affect lipid profiles in non-diabetic and diabetic populations. We evaluated the relationship between Apo E phenotype and fasting lipid plasma levels in type 2 diabetes patients.

METHODS

Two hundred and ten French type 2 diabetic patients (115 men and 95 women) without any lipid lowering drugs were studied. Fasting lipids were measured by usual methods and Apo E genotype was established for each patient: PCR was followed by digestion of the amplification product with restriction enzymes and separation of the fragments by polyacrylamide gel.

RESULTS

Genotypes epsilon3/epsilon3, epsilon2/epsilon3 and epsilon3/epsilon4, epsilon2/epsilon2 and epsilon2/epsilon4 were found in 68.1%, 14.8%, 15.7%, 1.0% and 0.5%, respectively. No patient had the epsilon4/epsilon4 genotype. Lipid plasma levels were compared between E3 group (epsilon3/epsilon3) as a reference and E2 (epsilon2/epsilon2 or epsilon2/epsilon3) or E4 (epsilon3/epsilon4 or epsilon2/epsilon4). Total cholesterol, LDL cholesterol and Apo B levels were lower in the E2 group. Total cholesterol, LDL cholesterol and Apo B levels were higher in the E4 group. HDL cholesterol levels were increased in the E4 group, as only previously observed in Japanese populations.

CONCLUSION

These results agree with those already reported in diabetic patients of several western European countries. E4 allele carriers have a greater cardio-vascular risk and this could be partially explained by the metabolic variation in lipid metabolism induced by E4 with higher LDL cholesterol and Apo B levels. These results observed in French diabetic subjects without any lipid-lowering drugs may be used as a reference for other studies performed in France.