Association of apolipoprotein E phenotype with hypertension in Japanese-Americans: data from the Hawaii-Los Angeles-Hiroshima Study

Association between ApoE polymorphism and hypertension: A meta-analysis of 28 studies including 5898 cases and 7518 controls

Hypertension is one of the most common chronic diseases, constituting an independent risk factor for many diseases. Our study aimed to evaluate the association between apolipoprotein E (ApoE) genetic polymorphism and hypertension, and to provide evidence for the etiology of hypertension. Case-control studies of ApoE polymorphism and hypertension, which were included in PubMed, Embase, Web of Science, Medline, WanFang, Vip, and CNKI information databases, were selected and evaluated according to criteria of inclusion and exclusion. Eligible data were extracted and pooled, and were analyzed and assessed using Stata 12.0. Random-effect models were used when heterogeneity existed in between-study, and fixed-effect models were applied otherwise. A total of 28 studies that consisted of 5898 cases with hypertension and 7518 controls were selected. Alleles and genotypes of ApoE between cases and controls were compared. For ApoE alleles, we observed the contrast of ApoE ε2 versus ε3 allele yielded a pooled OR of 0.99 (95% CI: 0.87-1.11; P = 0.823), whereas the contrast of ε4 versus ε3 allele yielded a pooled OR of 1.95 (95% CI: 1.50-2.54; P < 0.001). For ApoE genotypes, compared with ε3/ε3 genotype, genotypes (ε2/ε2 and ε2/ε3) showed a possible association with hypertension (OR = 0.88; 95% CI: 0.79-0.99; P = 0.033), and genotypes (ε3/ε4 and ε4/ε4) had a 2.08-fold risk of developing hypertension (OR = 2.08; 95% CI: 1.58-2.74; P < 0.001). There is the association between ApoE polymorphism and hypertension: the genotypes carrying ε2 allele may be a protective factor, and the ApoE ε4 allele and the genotypes carrying ε4 allele may be risk factors for hypertension.

Age-related trends of blood pressure levels by apolipoprotein E genotype: the Bambuì Cohort Study of Ageing (1997-2008)

The role of apolipoprotein E (apoE) polymorphisms in regulating blood pressure (BP) is still not clear. The aim of this study was to examine longitudinal changes in BP levels by apoE genotypes in a population-based prospective cohort of elderly subjects, and explore interactions with plasma lipids and uric acid. Subjects whose apoE genes had been genotyped at baseline (1408, representing 80.8% of all the elderly residents in Bambuì city, south-eastern Brazil; age range 60-95 years) were included in the analysis. Repeated BP measurements were obtained in four waves. Multi-level random-effects pattern-mixture models were used to evaluate the age-related BP trajectories, accounting for non-ignorable dropouts/deaths and handling heterogeneities as random parameter variations. Subjects with the ɛ4/4 genotype and high levels of low-density lipoprotein cholesterol had higher systolic BP levels at 60 years of age than those with the other genotypes (154.5 vs. 133.2 mm Hg, P=0.020), but this was not the case among the older subjects. Systolic BP increased more rapidly with age in the ɛ2 carriers, leading to significantly higher levels among the oldest. This relationship seemed to be modulated by uric acid levels, as it was present in the subjects with the ɛ2/3 genotype and high uric acid levels, and in those with the ɛ2/4 genotype and low or normal uric acid levels. The differences in systolic BP between the genotypes were age dependent, and the shift between the ɛ4 and ɛ2 alleles suggest that these alleles are involved in the different mechanisms leading to increased BP in middle-aged and elderly subjects.

The association between apolipoprotein E gene polymorphisms and essential hypertension: a meta-analysis of 45 studies including 13,940 cases and 16,364 controls

The apolipoprotein E single-nucleotide polymorphisms are among the potential candidate genes that may serve as modulators in susceptibility to essential hypertension. In an effort to clarify earlier inconclusive results, we performed a meta-analysis of population-based case-control genetic association studies. Random-effects methods were applied on summary data in order to combine the results of the individual studies. We identified in total 45 studies, including 13 940 hypertensive cases and 16 364 controls. The contrast of E4 carriers versus non-carriers yielded an overall odds ratio (OR) of 1.16 (95% confidence interval (CI): 1.02, 1.31), whereas the contrast of E4 allele versus the others in a subtotal of 6617 cases and 7330 controls, yielded an OR of 1.39 (95% CI: 1.12, 1.72). There was moderate evidence of publication bias in both contrasts, which was eliminated after excluding studies not in Hardy-Weinberg equilibrium. Subgroup analyses revealed that significant estimates arose from studies on Asian populations, as opposed to the Caucasian ones. Furthermore, no evidence of publication bias was demonstrated in the comparisons within this subgroup. Our results are consistent with recent meta-analyses but show that the association is weaker than that has been previously demonstrated. Further studies are needed in order to fully address questions about the etiological mechanism of the particular association, as well as to study the effect in populations of African descent.

Association of ApoE polymorphisms with prevalent hypertension in 1406 older adults: the Bambuí Health Aging Study (BHAS)

Apolipoprotein E (ApoE) polymorphism influences lipid metabolism, but its association with arterial hypertension is controversial. The objective of this study was to examine the association between ApoE polymorphism and prevalent hypertension in a large unselected population of older adults. Participants from the baseline of the Bambuí Health Aging Study whose ApoE genes had been genotyped were selected for this study (N = 1406, aged 60-95 years). These subjects represented 80.7% of the total elderly residents in Bambuí city, MG, Brazil. Hypertension was defined as a systolic blood pressure > or =140 mmHg and/or a diastolic blood pressure > or =90 mmHg, or the use of anti-hypertensive medication. The exposure variable was the ApoE genotype as follows: epsilon3 carriers, epsilon3epsilon3; epsilon2 carriers, epsilon2epsilon2 or epsilon2epsilon3, and epsilon4 carriers, epsilon3epsilon4 or epsilon4epsilon4. Potential confounding variables were age, gender, traditional cardiovascular risk factors, uric acid, and creatinine levels. The prevalence of hypertension was 61.3%. Compared with the epsilon3 homozygotes, neither the epsilon2 nor the epsilon4 carrier status was associated with hypertension (adjusted prevalence ratios = 0.94, 95%CI = 0.83-1.07 and 0.98, 0.89-1.07, respectively). On the other hand, the epsilon2 allele carriers had lower LDL cholesterol levels (P < 0.001) and the epsilon4 carriers had higher LDL cholesterol levels (P = 0.036). This study provides epidemiologic evidence that the ApoE genotype is not associated with prevalent hypertension in old age.