Interactions between lifestyle-related factors and the ApoE polymorphism on plasma lipids and apolipoproteins. The EARS Study. European Atherosclerosis Research Study

Exercise modulates APOE expression in brain cortex of female APOE3 and APOE4 targeted replacement mice

Apolipoprotein E (ApoE) is the main cholesterol carrier of the brain and the ε4 gene variant (APOE4) is the most prevalent genetic risk factor for Alzheimer's disease (AD), increasing risk up to 15-fold. Several studies indicate that APOE4 modulates critical factors for neuronal function, including brain-derived neurotrophic factor (BDNF) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). Both proteins show exercise-induced upregulation, which is presumed to mediate many of the beneficial effects of physical activity including improved cognition; however, there is variability in results between individuals potentially in-part due to genetic variations including APOE isoform. This study aimed to determine if the two most prevalent human APOE isoforms influence adaptive responses to exercise-training. Targeted replacement mice, homozygous for either APOE3 or APOE4 were randomized into exercised and sedentary groups. Baseline locomotor function and voluntary wheel-running behavior was reduced in APOE4 mice. Exercised groups were subjected to daily treadmill running for 8 weeks. ApoE protein in brain cortex was significantly increased by exercise in both genotypes. PGC-1α mRNA levels in brain cortex were significantly lower in APOE4 mice, and only tended to increase with exercise in both genotypes. Hippocampal BDNF protein were similar between genotypes and was not significantly modulated by treadmill running. Behavioral and biochemical variations between APOE3 and APOE4 mice likely contribute to the differential risk for neurological and vascular diseases and the exercise-induced increase in ApoE levels suggests an added feature of the potential efficacy of physical activity as a preventative and therapeutic strategy for neurogenerative processes in both genotypes.

Apolipoprotein E Genotype Moderation of the Association Between Physical Activity and Brain Health. A Systematic Review and Meta-Analysis

Introduction

Possession of one or two e4 alleles of the apolipoprotein E (APOE) gene is associated with cognitive decline and dementia risk. Some evidence suggests that physical activity may benefit carriers of the e4 allele differently.

Method

We conducted a systematic review and meta-analysis of studies which assessed APOE differences in the association between physical activity and: lipid profile, Alzheimer's disease pathology, brain structure and brain function in healthy adults. Searches were carried out in PubMed, SCOPUS, Web of Science and PsycInfo.

Results

Thirty studies were included from 4,896 papers screened. Carriers of the e4 allele gained the same benefit from physical activity as non-carriers on most outcomes. For brain activation, e4 carriers appeared to gain a greater benefit from physical activity on task-related and resting-state activation and resting-state functional connectivity compared to non-carriers. Post-hoc analysis identified possible compensatory mechanisms allowing e4 carriers to maintain cognitive function.

Discussion

Though there is evidence suggesting physical activity may benefit e4 carriers differently compared to non-carriers, this may vary by the specific brain health outcome, perhaps limited to brain activation. Further research is required to confirm these findings and elucidate the mechanisms.

Genetic variants related to physical activity or sedentary behaviour: a systematic review

BACKGROUND

Research shows that part of the variation in physical activity and sedentary behaviour may be explained by genetic factors. Identifying genetic variants associated with physical activity and sedentary behaviour can improve causal inference in physical activity research. The aim of this systematic review was to provide an updated overview of the evidence of genetic variants associated with physical activity or sedentary behaviour.

METHODS

We performed systematic literature searches in PubMed and Embase for studies published from 1990 to April 2020 using keywords relating to "physical activity", "exercise", "sedentariness" and "genetics". Physical activity phenotypes were either based on self-report (e.g., questionnaires, diaries) or objective measures (e.g., accelerometry, pedometer). We considered original studies aiming to i) identify new genetic variants associated with physical activity or sedentary behaviour (i.e., genome wide association studies [GWAS]), or ii) assess the association between known genetic variants and physical activity or sedentary behaviour (i.e., candidate gene studies). Study selection, data extraction, and critical appraisal were carried out by independent researchers, and risk of bias and methodological quality was assessed for all included studies.

RESULTS

Fifty-four out of 5420 identified records met the inclusion criteria. Six of the included studies were GWAS, whereas 48 used a candidate gene approach. Only one GWAS and three candidate gene studies were considered high-quality. The six GWAS discovered up to 10 single nucleotide polymorphisms (SNPs) associated with physical activity or sedentariness that reached genome-wide significance. In total, the candidate gene studies reported 30 different genes that were associated (p < 0.05) with physical activity or sedentary behaviour. SNPs in or close to nine candidate genes were associated with physical activity or sedentary behaviour in more than one study.

CONCLUSION

GWAS have reported up to 10 loci associated with physical activity or sedentary behaviour. Candidate gene studies have pointed to some interesting genetic variants, but few have been replicated. Our review highlights the need for high-quality GWAS in large population-based samples, and with objectively assessed phenotypes, in order to establish robust genetic instruments for physical activity and sedentary behaviour. Furthermore, consistent replications in GWAS are needed to improve credibility of genetic variants.

TRIAL REGISTRATION

Prospero CRD42019119456 .

Lack of association between genetic variants in the 19q13.32 region and CHD risk in the Algerian population: a population-based nested case-control study

BACKGROUND

Coronary Heart Disease (CHD) is a major cause of morbidity and mortality over the world; intermediate traits associated with CHD commonly studied can be influenced by a combination of genetic and environmental factors.

OBJECTIVE

We found previously significant association between three genetic polymorphisms, and the lipid profile variations in the Algerian population. Considering these findings, we therefore decided to assess the relationships between these polymorphisms and CHD risk.

METHODS

We performed a population-based, cross-sectional study, of 787 individuals recruited in the city of Oran, in which, a nested case-control study for MetS, T2D, HBP, obesity and CHD were performed. Subjects were genotyped for four SNP rs7412, rs429358 rs4420638 and rs439401 located in the 19q13.32 region.

RESULTS

The T allele of rs439401 confers a high risk of hypertension with an odds ratio (OR) of 1.46 (95% CI [1.12-1.9], p = 0.006) and the G allele of rs4420638 was significantly associated with a decreased risk of obesity, OR 0.48 (95% CI [0.29-0.81], p = 0.004). No associations were found for MetS, T2D and CHD.

CONCLUSION

Although the studied genetic variants were not associated with the risk of CHD, the 19q13.32 locus was associated with some of the cardiometabolic disorders in Algerian subjects.

Triglycerides Revisited to the Serial

This review discusses the role of triglycerides (TGs) in the normal cardiovascular system as well as in the development and clinical manifestation of cardiovascular diseases. Regulation of TGs at the enzymatic and genetic level, in addition to their possible relevance as preclinical and clinical biomarkers, is discussed, culminating with a description of available and emerging treatments. Due to the high complexity of the subject and the vast amount of material in the literature, the objective of this review was not to exhaust the subject, but rather to compile the information to facilitate and improve the understanding of those interested in this topic. The main publications on the topic were sought out, especially those from the last 5 years. The data in the literature still give reason to believe that there is room for doubt regarding the use of TG as disease biomarkers; however, there is increasing evidence for the role of hypertriglyceridemia on the atherosclerotic inflammatory process, cardiovascular outcomes, and mortality.

Influence of Abdominal Obesity on the Lipid-Lipoprotein Profile in Apoprotein E2/4 Carriers: The Effect of an Apparent Duality

Background. Apolipoprotein (Apo) E plays a key role in the handling of lipoprotein particles with ApoE2 and ApoE4 frequently having opposite effects compared to ApoE3. Some individuals simultaneously carry both E2 and E4 alleles. The impact of the ApoE2/4 genotype on lipid concentrations and its consequences on health remain poorly documented. Objective. This study compared the lipid profile between ApoE2/4 carriers and other ApoE genotypes in relation to the waist circumference. Methods. Cholesterol, triglyceride (TG), and ApoB concentrations were measured among 2,680 Caucasians. Multivariate logistic regression models were used to estimate the contribution of ApoE2/4 to various dyslipidemic profiles associated with abdominal obesity. Results. In presence of abdominal obesity, the lipid profile was as deteriorated in ApoE2/4 carriers as in carriers of other ApoE genotypes. There was a more pronounced effect on TG-rich lipoproteins, particularly in ApoE2/2 (a feature of type III dysbetalipoproteinemia), and non-high-density lipoprotein (HDL) cholesterol in ApoE4/4. Compared to ApoE2/2, ApoE2/4 carriers presented lower very-low-density lipoprotein (VLDL) cholesterol concentrations and VLDL-cholesterol/TG ratios, with or without obesity, and higher low-density lipoprotein (LDL) cholesterol concentrations. Conclusion. In presence of abdominal obesity, the influence of the ApoE2 allele could be less pronounced than that of ApoE4 among ApoE2/4 individuals.

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.

Cross-sectional and longitudinal associations between serum uric acid and metabolic syndrome

Research on the importance of serum uric acid (SUA) as a contributing metabolic factor to cardiovascular diseases has conducted to conflicting results, with most studies assuming a cross-sectional design. The aim of this study was to evaluate the association of SUA and metabolic syndrome (MetS) and its features. A representative sample of 2,485 individuals aged ≥18 years was randomly selected from the non-institutionalized resident population of Porto, Portugal. A total of 1,054 eligible subjects were included for the longitudinal analyses. Hyperuricemia was defined as SUA ≥70 mg/L in men and ≥60 mg/L in women. MetS was defined according the Joint Interim (2009) criteria. Associations were estimated using Poison regression and binomial models. In the cross-sectional analysis, subjects with hyperuricemia had a 2.10-fold increased risk of MetS as compared with normouricemic subjects (PR = 2.10, 95% CI: 1.68-2.63). Among MetS features, high triglycerides presented the strongest association with hyperuricemia (PR = 2.32, 95% CI: 1.84-2.91). The MetS crude incidence rate was 4.5/100 person-year (95% CI: 3.9-5.2) in normal uricemic and 13.0/100 person-year (95% CI: 8.5-20.0) in hyperuricemic participants. Using a multivariate longitudinal approach, hyperuricemia was positively associated with MetS incidence rate ratios (IRR = 1.73, 95% CI: 1.08-2.76). One standard deviation increase of SUA concentration was associated with a 1.22-fold increase in MetS risk (IRR = 1.22, 95% CI: 1.05-1.42). Elevated SUA presented the strongest association with high-triglycerides concentration (IRR = 1.44, 95%: 1.22-1.71) and waist circumference (IRR = 1.25, 95%: 1.05-1.49). The independent positive association between SUA and MetS suggested by this longitudinal study supports that SUA might be a risk factor for MetS.

Interaction of apolipoprotein E genotype with smoking and physical inactivity on coronary heart disease risk in men and women

OBJECTIVE

Apolipoprotein E genotype (APOE) polymorphism affects lipid levels and coronary heart disease (CHD) risk. However, these associations may be modified by lifestyle factors. Therefore, we studied whether smoking, physical inactivity or overweight interact with APOE on cholesterol levels and CHD risk.

METHODS

Combining two Swedish case-control studies yielded 1735 CHD cases and 4654 population controls (3747 men, 2642 women). Self-reported questionnaire lifestyle data included smoking (ever [current or former regular] or never) and physical inactivity (mainly sitting leisure time). We obtained LDL cholesterol levels and APOE genotypes. CHD risk was modelled using logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for relevant covariates.

RESULTS

Smoking interacted with APOE on CHD risk; adjusted ORs for ever versus never smoking were 1.45 (95% CI 1.00-2.10) in ɛ2 carriers, 2.25 (95% CI 1.90-2.68) in ɛ3 homozygotes and 2.37 (95% CI 1.85-3.04) in ɛ4 carriers. Female ɛ4 carriers had OR 3.62 (95% CI 2.32-5.63). The adjusted ORs for physical inactivity were 1.09 (95% CI 0.73-1.61), 1.34 (95% CI 1.12-1.61), and 1.79 (95% CI 1.38-2.30) in ɛ2, ɛ3ɛ3 and ɛ4 groups, respectively. No interaction was seen between overweight and APOE for CHD risk, or between any lifestyle factor and APOE for LDL cholesterol levels.

CONCLUSION

The APOE ɛ2 allele counteracted CHD risk from smoking in both genders, while the ɛ4 allele was seen to potentiate this risk mainly in women. Similar ɛ2 protection and ɛ4 potentiation was suggested for CHD risk from physical inactivity.

E2 allele of the apolipoprotein E gene polymorphism is predictive for obesity status in Roma minority population of Croatia

Background and Aims

The Roma (Gypsies) are a transnational minority, founder population characterized by unique genetic background modeled by culturally determined endogamy. The present study explores whether the widely found cardiovascular diseases (CVD) risk effects of ACE I/D, APOE (ε2, ε3, ε4), eNOS-VNTR and LEP G2548A polymorphisms can be replicated in this specific population.

Methods and Results

The community-based study was carried on 208 adult Bayash Roma living in rural settlements of eastern and northern Croatia. Risk effect of four CVD candidate polymorphisms are related to the most prominent classical CVD risk phenotypes: obesity indicators (body mass index and waist circumference), hypertension and hyperlipidemia (triglycerides, HDL and LDL cholesterol). For all of them the standard risk cut-offs were applied. The extent to which the phenotypic status is related to genotype was assessed by logistic regression analysis. The strongest associations were found for ε2 allele of the APOE as a predictor of waist circumference (OR 3.301; 95%CI 1.254-8.688; p = 0.016) as well as for BMI (OR 3.547; 95%CI 1.471-8.557; p = 0.005). It is notable that ε3 allele of APOE gene turned out to be a protective genetic factor determining low lipid levels.

Conclusion

The strength of the relation and the similarity of the results obtained for both tested indicators of obesity provide firm evidence that APOE plays an important role in obesity development in the Roma population.

Apolipoprotein E gene is related to mortality only in normal weight individuals: the Rotterdam Study

Objective To investigate the relationship between the apolipoprotein E (APOE) gene and the risk of mortality in normal weight, overweight and obese individuals. Methods and Results In a population-based study of 7,983 individuals aged 55 years and older, we compared the risks of all-cause and coronary heart disease (CHD) mortality by APOE genotype, both overall and in subgroups defined by body mass index (BMI). We found significant evidence for interaction between APOE and BMI in relation to total cholesterol (p = 0.04) and HDL cholesterol (p < 0.001). Overall, APOE*2 carriers showed a decreased risk of all-cause mortality. Analyses within BMI strata showed a beneficial effect of APOE*2 only in normal weight persons (adjusted hazard ratio (HR) 0.7[95% CI 0.5–0.9]). APOE*2 was not associated with a lower risk of all-cause mortality in overweight or obese persons. The effect of APOE*2 in normal weight individuals tended to be due to the risk of CHD mortality (adjusted HR 0.5 [95% CI 0.2–1.2]). Conclusion The APOE*2 allele confers a lower risk of all-cause mortality only to normal weight individuals.

Influencia de los factores genéticos y ambientales en el metabolismo lipídico y riesgo cardiovascular asociado al gen apoE

The apolipoprotein E (ApoE) plays an important role in lipid metabolism. This apoprotein presents three major isoforms (apoE2, apoE3 and apoE4) that modulate lipid levels. Carriers of the apoE4 allele have higher total and LDL-cholesterol plasma concentration and a greater coronary risk, particularly for myocardial infarction. Nevertheless, not all the people with this allele develop the disease, which suggests that other genetic or environmental factors are necessary for its total expression. In this review, we will analyze the importance of several polymorphisms in the apoE gene promoter region, as well as various environmental factors, including diet, in the association of this gene with lipid metabolism and cardiovascular risk.

The effect of the APOE polymorphism on HDL-C concentrations depends on the cholesterol ester transfer protein gene variation in a Southern European population

BACKGROUND

Apolipoprotein E (ApoE) locus has consistently shown a significant association with low-density lipoprotein cholesterol (LDL-C). However, its impact on high-density lipoprotein cholesterol (HDL-C) has been highly controversial suggesting that it may be context-dependent. We examined the gene-gene interaction between the common ApoE and the CETP polymorphisms in determining HDL-C concentrations in men and women from the general population.

METHODS

550 unrelated Caucasian subjects were randomly selected from a Mediterranean Region in Spain. Plasma lipids, anthropometric, clinical and lifestyle variables were measured. Common ApoE and CETP-TaqIB polymorphisms were determined.

RESULTS

We have found a gene-gene interaction between and ApoE and the CETP loci in determining HDL-C concentrations. Thus, after adjustment for gender, age, body mass index, tobacco smoking, alcohol consumption, physical exercise and medication, carriers of the E4 allele had lower HDL-C concentrations [mean and (standard error): 40.1 (2.6) mg/dL] than E2 subjects [47.7 (3.2) mg/dL; p=0.019], and even lower than those of the E3 subjects [44.7 (1.4) mg/dL; p=0.042], only if they had the B1B1 genotype. However, mean HDL-C concentrations were higher among those with E4 allele carrying the B2 allele at the CETP gene locus [50.5 (2.3) mg/dL], and lower among E2 subjects carrying the B2 allele [45.5 (2.6) mg/dL]. This interaction was observed in both men and women. This gene-gene interaction remained statistically significant even after additional adjustment for triglycerides.

CONCLUSIONS

The effect of the ApoE polymorphism on HDL-C concentrations depends on the CETP polymorphism, explaining some of the controversial results previously reported for this polymorphism.

Associations between apolipoprotein E genotype and circulating F2-isoprostane levels in humans

Apolipoprotein E (apoE), an important determinant of plasma lipoprotein metabolism, has three common alleles (epsilon2, epsilon3, and epsilon4). Population studies have shown that the risk of diseases characterized by oxidative damage, such as coronary heart disease and Alzheimer's disease, is significantly higher in epsilon4 carriers. We evaluated the association between apoE genotypes and plasma F2-isoprostane levels, an index of lipid peroxidation, in humans. Two hundred seventy-four healthy subjects (104 males, 170 females; 46.9 +/- 13.0 yr; 200 whites, 74 blacks; 81 nonsmokers, 64 passive smokers, and 129 active smokers) recruited for a randomized clinical antioxidant intervention trial were included in this analysis. ApoE genotype was determined by PCR and restriction enzyme digestion. Free plasma F2-isoprostane was measured by GC-MS. Genotype groups were compared using multiple regression analysis with adjustment for sex, age, race, smoking status, body mass index, plasma ascorbic acid, and beta-carotene. Subjects with epsilon3/epsilon4 and epsilon4/epsilon4 genotype (epsilon4-carriers) and with epsilon2/epsilon3 and epsilon3/epsilon3 (non-epsilon4-carriers) were pooled for analysis. In subjects with high cholesterol levels (total cholesterol above 200 mg/dl), plasma F2-isoprostane levels were 29% higher in epsilon4 carriers than in non-epsilon4-carriers (P= 0.0056). High-cholesterol subjects that are epsilon4 carriers have significantly higher levels of lipid peroxidation as assessed by circulating F2-isoprostane levels.

Obesity and alcohol modulate the effect of apolipoprotein E polymorphism on lipids and insulin

OBJECTIVE

To assess the interaction between apolipoprotein (apo) E polymorphism, alcohol consumption, and BMI on insulin, lipid, and lipoprotein levels in men.

RESEARCH METHODS AND PROCEDURES

Cross-sectional study of 266 healthy men without hypolipidemic or antidiabetic drug treatment. BMI, apo E polymorphisms, insulin, and lipid and lipoprotein levels were assessed. Alcohol consumption was assessed by questionnaire. epsilon2/epsilon4 carriers were excluded from the analysis.

RESULTS

On bivariate analysis, epsilon2 carriers had lower levels of total and low-density lipoprotein cholesterol and higher levels of apo E and lipoparticle B:E than epsilon3 carriers, the opposite being found for epsilon4 carriers compared with epsilon3 carriers; epsilon4 carriers also had significantly higher insulin levels. On multivariate analysis, significant interactions (p < 0.04) between apo E alleles and increased BMI were found for total and low-density lipoprotein cholesterol and insulin levels, the increase in those parameters with BMI being stronger among epsilon4 carriers than among epsilon3 or epsilon2 carriers. Significant interactions (p < 0.02) between apo E alleles and alcohol consumption were also found for apo B levels, which increased in epsilon2 carriers but remained relatively stable in epsilon3 and tended to decrease in epsilon4 carriers.

DISCUSSION

These data suggest that effects of apo E alleles on lipids and insulin levels are partly dependent on environmental variables such as BMI and alcohol intake. These findings highlight the importance of gene x environment interactions on the deleterious effect of obesity on cardiovascular risk factors.

Association of apolipoprotein E polymorphism with blood lipids and maximal oxygen uptake in the sedentary state and after exercise training in the HERITAGE family study

The relationship of apolipoprotein E (apo E) genotypes to plasma lipid and maximal oxygen uptake (Vo(2max)) was studied in the sedentary state and after a supervised exercise training program in black and white men and women. At baseline, the apo E 2/3 genotype was associated with the lowest, and apo E 3/4 and E4/4 with the highest low-density liporpotein (LDL) cholesterol and apo B levels in men and women of both races, while female (not male) carriers of apo E3 had higher high-density lipoprotein (HDL) cholesterol levels than carriers of other genotypes. Very-low-density lipoprotein (VLDL) cholesterol and triglyceride levels were significantly higher in carriers of both apo E2 and apo E4 in white men only. Racial and sex differences were noted in lipid responses to exercise training across genotypes with a significantly greater increase in HDL cholesterol observed only in white female carriers of apo E 2/3 and E3/3, as compared to apo E4/4. Apo E polymorphism was not found to be associated with Vo(2max) levels either in the sedentary state nor the Vo(2max) response to exercise training, contrary to previous reports.

Effect of the APOE-491A/T promoter polymorphism on apolipoprotein E levels and risk of Alzheimer disease: The Rotterdam Study

The apolipoprotein E (APOE) gene is involved in lipid transport. A common polymorphism in this gene with the APOE*2, APOE*3, and APOE*4 alleles influences plasma levels of apolipoprotein E and cholesterol. Besides its role in lipid transport, the APOE*4 allele is a genetic risk factor for Alzheimer disease (AD). Recently, a polymorphism in the APOE promoter region was found to be involved in plasma apolipoprotein E levels and was found associated with AD. We studied the effect of this -491A/T promoter polymorphism on plasma apolipoprotein E levels and risk for AD in a population-based case-control study. We found that there was a modest but statistically significant effect of the -491A/T polymorphism on plasma apolipoprotein E levels independent of the APOE genotype. The lowest plasma levels were measured for the AA genotype, highest levels for the TT genotype, and intermediate levels for the heterozygotes. There was a small effect of the -491 AA genotype on AD risk that disappeared after adjusting for APOE genotypes. Our data suggest that the -491A/T polymorphism has an APOE genotype-independent effect on plasma apolipoprotein E levels but no APOE-independent effect on AD risk.

Evidence of reduced coronary artery disease risk for apolipoprotein epsilon2/3 heterozygotes

BACKGROUND: Polymorphism in the gene for apolipoprotein E (apo E) influences lipid metabolism. Relative to the epsilon3 allele, the epsilon4 allele tends to increase and the epsilon2 allele tends to decrease total and serum cholesterol, but uncertainty remains concerning an influence on the risk of coronary artery disease (CAD). It is possible that the influence of apo E alleles on CAD risk is influenced by the age of subjects studied. In this study, we examine the influence of the epsilon2 and epsilon4 alleles on the risk of CAD in relatively young subjects. METHODS: We determined the apo E genotype of 564 Caucasian CAD subjects below 50 years of age presenting with symptomatic CAD, either with or without prior myocardial infarction, and documented by angiography, and 639 similarly aged Caucasian control subjects without symptomatic CAD randomly selected from the community. RESULTS: The frequency of subjects with the epsilon2/3 genotype was significantly lower in CAD subjects than controls (6 vs. 11%, P<0.01) and, relative to epsilon3/3, the epsilon2/3 genotype was associated with a significant reduction in total and LDL-cholesterol in male and female control subjects. In contrast, there was no difference in the frequency of epsilon4/4 or epsilon4/3 genotypes in CAD cases and controls (30 vs. 26%, NS), and the latter genotypes had little influence on total or LDL-cholesterol. CONCLUSION: The results indicate a beneficial effect of the epsilon2/3 genotype not only on LDL cholesterol but in decreasing the risk of CAD in Caucasians at a young age.

O componente genético da determinação dos lipídeos séricos

Os níveis de lipídeos séricos são características multifatoriais determinadas por um grande número de fatores genéticos e ambientais. A identificação do componente genético dessas características tem sido intensamente investigada nos últimos anos. Esses estudos têm enfocado principalmente polimorfismos nos genes que codificam proteínas estruturais e enzimas relacionadas com o metabolismo de lipídeos. Estudos mais recentes mostraram que o efeito desses polimorfismos depende em parte das interações dos diferentes genótipos com os fatores de risco clássicos tais como tabagismo, sobrepeso ou sedentarismo. A variabilidade encontrada nesses genes parece também influir na resposta a fármacos comumente utilizados no tratamento das hiperlipidemias.

APOE polymorphism and the hypertriglyceridemic effect of dietary sucrose

BACKGROUND

The E4 allele of the apolipoprotein gene (APOE) is associated with a greater serum cholesterol response to dietary changes in fat and cholesterol. However, less is known about the interaction between APOE polymorphism and other macronutrients in the diet.

OBJECTIVE

We evaluated the interaction between APOE polymorphism and dietary fat and carbohydrate, particularly sucrose, in relation to serum lipid concentrations.

DESIGN

A total of 284 men and 130 women with coronary artery disease (mean age: 61 y; range: 33-74 y) participated in the cross-sectional EUROASPIRE study. Serum lipids and fatty acids in cholesteryl esters (CEs) were measured and APOE genotypes were determined. Dietary intake was examined by using a 4-d food record.

RESULTS

Patients were grouped by APOE genotype: E2 (E2/E2 and E2/E3; n = 21), E3 (E3/E3; n = 245), and E4 (E4/E2, E4/E3, and E4/E4; n = 148). Patients with the E2 allele had lower LDL-cholesterol concentrations and tended to have higher triacylglycerol concentrations than did patients with the E3 or E4 allele; concentrations were not significantly different between the last 2 groups. In regression analysis, significant predictors of serum triacylglycerol were the interaction between sucrose intake and the E2 allele, proportion of n-3 fatty acids in CEs, body mass index, and diabetes. A high sucrose intake was associated with high triacylglycerol concentrations only in patients with the E2 allele. Interaction between saturated fat intake and the E2 allele, proportion of linoleic acid in CEs, and fiber intake predicted serum cholesterol.

CONCLUSION

Coronary artery disease patients with the E2 allele will likely have a greater triacylglycerol response to high dietary sucrose intakes than will patients with the E3 or E4 allele.

Apoprotein E genotype and the response of serum cholesterol to dietary fat, cholesterol and cafestol

Previous studies on the effect of apoprotein E (APOE) polymorphism on the response of serum lipids to diet showed inconsistent results. We therefore studied the effect of apoprotein E polymorphism on responses of serum cholesterol and lipoproteins to various dietary treatments. We combined data on responses of serum cholesterol and lipoproteins to saturated fat, to trans-fat, to dietary cholesterol, and to the coffee diterpene cafestol with newly obtained data on the apoprotein E polymorphism in 395 mostly normolipidemic subjects. The responses of low-density lipoprotein (LDL-) cholesterol to saturated fat were 0.08 mmol/l larger in subjects with the APOE3/4 or E4/4 genotype than in those with the APOE3/3 genotype (95% confidence interval: -0.01-0.18 mmol/l). In contrast, responses of LDL-cholesterol to cafestol were 0.11 mmol/l smaller in subjects with the APOE3/4 or E4/4 genotype than in those with the APOE3/3 genotype (95% confidence interval: -0.29-0.07 mmol/l). Responses to dietary cholesterol and trans-fat did not differ between subjects with the various APOE genotypes. In conclusion, the APOE genotype may affect the response of serum cholesterol to dietary saturated fat and cafestol in opposite directions. However, the effects are small. Therefore, knowledge of the APOE genotype by itself may be of little use in the identification of subjects who respond to diet.

Apolipoprotein E genotypes predict attendance rates at lipid clinic

Except for the rare epsilon22 genotype it remains largely unsettled whether apolipoprotein E genotype influences an individual's referral to lipid clinics. To test this hypothesis, we compared genotype distributions among 156 hypercholesterolemic and 83 hypertriglyceridemic patients attending a lipid clinic with that among 9241 individuals sampled from the Danish general population. The relative genotype frequencies of epsilon22, epsilon32, epsilon42, epsilon33, epsilon43, and epsilon44 were 0.005, 0.126, 0.026, 0.564, 0.251, and 0.027 in the general population, which differed from genotype frequencies in both hypercholesterolemic (chi2: P = 0.01) and hypertriglyceridemic patients (chi2: P < 0.001). By comparison with epsilon33, epsilon44 predicted a 2-fold increase whereas epsilon32 predicted a 2-fold decrease in the attendance rate at the lipid clinic for hypercholesterolemic patients (95% confidence intervals: 1.1-4.3 and 0.2-0.9). Among hypertriglyceridemic patients, epsilon22, epsilon42, epsilon43, and epsilon44 versus epsilon33 predicted 13-, 3-, 1 1/2-, and 3-fold attendance rates at the lipid clinic, respectively (95% confidence intervals: 4.5-39.9, 1.2-8.4, 1.0-2.8, and 1.1-7.6). These findings are in accordance with the fact that epsilon44 raises cholesterol levels, epsilon32 reduces cholesterol levels, and epsilon22, epsilon42, epsilon43, and epsilon44 raise triglyceride levels in comparison with epsilon33. These data suggest that hypercholesterolemic individuals carrying epsilon44 and hypertriglyceridemic individuals carrying epsilon22, epsilon42, epsilon43, or epsilon44 are relatively more often referred to lipid clinics than carriers of epsilon33.

Apolipoprotein E serum concentration and polymorphism in six European countries: the ApoEurope Project

As part of the ApoEurope Project, the apolipoprotein E (apo E) serum concentration and polymorphism were determined in 6934 healthy subjects aged 25-64 years recruited in six European countries: Finland; France; Greece; Northern Ireland; Portugal and Spain. Age and sex influenced apo E concentration with concentrations being significantly higher in men than in women for those aged between 25 and 44 years. The age effect differed between the sexes after the age of 44 years, displaying a linear increase in women and a plateau in men. As expected, the serum apo E concentration was highest in varepsilon2 carriers and lowest in varepsilon4 carriers in each country with a significantly higher frequency of the varepsilon4 allele in the northern regions. The main finding of this study was a clear increasing North-South gradient in serum apo E concentration independent of age, sex and apo E genotype. In subjects aged <45 years and with the varepsilon3/varepsilon3 genotype, apo E concentration was higher in the South-East (Greece) as compared to the North by 20% for men and 32% for women. In addition to the genetic polymorphism, the geographical area is an important factor to take into account when studying serum apo E concentration in multicentre studies and defining reference values.

Apolipoprotein epsilon2 allele is associated with an anti-atherogenic lipoprotein profile in children: The Columbia University BioMarkers Study

OBJECTIVE

We examined associations between allelic variation in the apo epsilon gene, which codes for apolipoprotein E, and plasma lipid levels in children.

MATERIALS AND METHODS

We analyzed genotype and fasting lipid levels, including lipid particle size by nuclear magnetic resonance spectroscopy, in 515 children from 297 families.

RESULTS

Children carrying the apo epsilon2 allele (1 or 2 epsilon2 alleles; n = 45) had higher mean high-density lipoprotein (HDL) cholesterol level (49.5 +/- 13.0 vs 42.4 +/- 8.9 mg/dL) and lower mean low-density lipoprotein (LDL) cholesterol level (82.2 +/- 48.6 vs 105.9 +/- 45.0 mg/dL) compared with apo epsilon3/epsilon3 children (n = 322). Mean HDL size was larger and mean level of the atheroprotective large HDL subpopulation was higher among apo epsilon2 carriers compared with epsilon3/epsilon3 children (9.5 +/- 0.4 vs 9.3 +/-.4 nm, and 32.8 +/- 9.9 vs 27.6 +/- 8.2 mg/dL). In multivariate models adjusting for age, sex, ethnicity, family history, body mass index, and fasting triglyceride level, the apo epsilon2 allele was independently predictive of higher levels of HDL cholesterol and the large HDL subpopulation and of lower level of LDL cholesterol.

CONCLUSION

The apo epsilon2 allele is associated with an anti-atherogenic lipid pattern in children.apolipoprotein epsilon, children, cholesterol.

Smoking influences the association between apolipoprotein E and lipids: the National Heart, Lung, and Blood Institute Family Heart Study

Apolipoprotein E allele 4 (apo epsilon4) and smoking each have been associated with an unfavorable lipid profile. We used data collected on 1,472 subjects in the National Heart, Lung, and Blood Institute Family Heart Study to assess whether smoking interacts with apo epsilon4 to influence the levels of plasma lipids. We dichotomized smoking and apo epsilon4 and used analysis of covariance to estimate the means of lipids. Smokers had lower body mass index, were younger, and consumed less fruits and vegetables. Among individuals without apo epsilon4, comparing nonsmokers with smokers, mean low density lipoprotein cholesterol (LDL) was 129.3 and 134.4 mg/dL, respectively, for women and 126.1 and 127.6 mg/dL, respectively, for men. Among subjects with an apo epsilon4 allele, corresponding means were 132.0, and 152.9 mg/dL, respectively, for women and 131.3 and 137.3 mg/dL, respectively, for men (Pfor interaction <0.001 for women and 0.11 for men). A similar interaction was observed for total cholesterol among women (P = 0.02). This study shows a statistically significant effect modification of the relation of apo epsilon4 to LDL and total cholesterol by smoking among women. Smoking may enhance genetic susceptibility to an unfavorable lipid profile among subjects with apo epsilon4.

[Apolipoprotein E gene polymorphism and risk of hypercholesterolemia: a case control study in a working population of Valencia]

BACKGROUND

The apolipoprotein E (apoE) gene is polymorphic with three common alleles (epsilon 2, epsilon 3, epsilon 4) whose allelic frequency and association with lipid levels varies from population to population. The aim of this study was to estimate the association between these genetic variants and the risk of hypercholesterolemia in a Mediterranean Spanish population.

PATIENTS AND METHODS

A case-control study in a working population from Valencia was carried out. A total of 330 cases (148 men and 182 women) with moderate hypercholesterolemia (total cholesterol > 200 mg/dl or with lipid lowering treatment) and age range 20 to 60 years, were identified. 330 normocholesterolemic controls matched by age and sex were selected. From all of them data of apoE genotype, body mass index, lipid and lipoprotein levels, socioeconomic and life-style variables were obtained.

RESULTS

The epsilon 2 allele frequency was statistically lower in cases (0.033) than in controls (0.086). The epsilon 4 allele frequency was higher in cases (0.115) than in controls (0.039). In the crude logistic regression analysis, the apoE polymorphism was related (p < 0.001) to the risk of hypercholesterolemia. After adjustment by age, body mass index, educational level, tobacco smoking, alcohol consumption and physical activity the epsilon 2 allele was associated with a lower risk of hypercholesterolemia (odds ratio [OR] = 0.36; 95% confidence interval (CI): 0.20-0.64), and the epsilon 4 allele was associated with a higher risk (OR = 3.04; 95% CI: 1.82-5.06).

CONCLUSIONS

The apoE genotype was significantly related to the risk of moderate hypercholesterolemia in the Mediterranean Spanish population.

Associations of apolipoprotein E concentration and polymorphism with lipids and apolipoprotein levels in Chinese from Beijing and Shanghai

The association of apolipoprotein E concentration and common polymorphism (codons 112/158) with lipid and apolipoprotein concentrations was studied in two Chinese healthy population samples from Beijing (n=99) and Shanghai (n=67). Body mass index and apolipoproteins E and AI and triglyceride concentrations were significantly different between the two populations (0.001<p<0.05), but apolipoprotein E common allele frequencies were not significantly different. Apolipoprotein E concentration was independently associated with apolipoproteins B and AI, total cholesterol and triglyceride concentrations in the Beijing group, but only with total cholesterol and apolipoprotein AI concentrations in the Shanghai group. Apolipoprotein E polymorphism was significantly associated with apolipoproteins E and AI, and triglyceride concentrations in the Beijing subjects (0.001<p<0.01), whereas apolipoprotein E polymorphism was significantly related only to apolipoprotein E concentration in the Shanghai group (p<0.001). This preliminary study with a limited number of subjects shows that the relations between both apolipoprotein E genotypes and concentration with lipid traits are not the same in the two studied Chinese populations.

Association of apolipoprotein E polymorphism with plasma lipids and Alzheimer's disease in a Southern Brazilian population

Apolipoprotein E (protein: apo E; gene: APOE) plays an important role in the multifactorial etiology of both Alzheimer's disease (AD) and lipid level concentrations. The polymerase chain reaction (PCR) was used to investigate the APOE gene polymorphism in 446 unrelated Caucasians, among them 23 AD patients, and 100 Afro-Brazilians living in Porto Alegre, Brazil. The frequencies of the APOE*2, APOE*3 and APOE*4 alleles were 0.075, 0.810 and 0.115 in Caucasians and 0.075, 0.700 and 0.225 in Afro-Brazilians, respectively (chi2 = 8.72, P = 0.013). A highly significant association was observed between the APOE*4 allele and AD in this population-based sample. The APOE*4 frequency in AD patients (39%) was about four times higher than in the general Caucasian population (11.5%). The influence of each of the three common APOE alleles on lipid traits was evaluated by the use of the average excess statistic. The E*2 allele is associated with lower levels of triglycerides and of total and non-HDL cholesterol in both men and women. Conversely, the E*4 allele is associated with higher levels of these traits in women only. The effect of APOE alleles was of greater magnitude in women.

Apolipoprotein E polymorphism in non-insulin-dependent diabetics of Mumbai, India and its effect on plasma lipids and lipoproteins

The role of apolipoproteinE (apoE) phenotypes in modulating the plasma lipid and lipoprotein levels was studied in a group of NIDDM patients and healthy individuals residing in Mumbai. The apoE phenotype frequencies were similar in the diabetic and healthy persons. The elevations in the lipid/lipoprotein levels were higher in diabetic subjects (53.3%) than in the controls (8%), showing the frequency of increase to be highest in the apoE4/4 group of diabetics, followed by apoE4/3 and apoE3/2 groups. In the controls as well, a similar trend was observed in different groups, indicating that the susceptibility to changes in lipid concentrations differs among apoE phenotypes. The apoE3/3 bearing individuals in both the categories showed close to normal lipid levels, suggesting it to be the wild type. The occurrence of apoE4 allele was higher than the apoE2 allele in diabetic individuals. Diabetic subjects with the apoE4 allele showed hypercholesterolemia, while those with apoE2 showed the presence of hypertriglyceridemia. One of the striking features of our work is a significant relationship between apoE4/3 phenotype in NIDDM persons and elevated levels of plasma triglyceride, thus suggesting a delayed catabolism of VLDL relative to production. In conclusion, the work suggests that the apoE2 and apoE4 alleles are associated with elevations in lipid levels and these changes are more pronounced in the diabetic individuals in whom most of the lipid levels were higher, indicating a gene environment/disease interaction.

Apolipoprotein E gene polymorphisms and serum cholesterol in healthy Irish adults: a proposed genetic marker for coronary artery disease risk

BACKGROUND

The apolipoprotein (Apo) E gene, and thus its gene product, plays a central and pervasive role in lipid metabolism by serving as a ligand for lipoprotein receptors. Polymorphisms of this gene have been associated with variation in lipid phenotypes in some Caucasian and Asian populations, but not in others. No such study has been carried out in a resident Irish population.

AIM

A study was designed to examine the relationship between serum cholesterols and Apo E genotype in a cohort of healthy Irish adults.

METHODS

One hundred healthy Irish adults, aged 19-65 years, were recruited from the Cork City area. Two fasting blood samples were collected from each subject. One was assayed for serum cholesterols--total and low-density lipoprotein (LDL), and high-density lipoprotein (HDL)--while the other sample was used for isolation of genomic DNA and determination of Apo E genotype.

RESULTS

While the E2 (12%) was the least prevalent, E3 was the most prevalent Apo E genotype (66%) in this group of healthy Irish adults. A significant Apo E gene-dosage effect was evident, whereby individuals with the Apo E2 genotype had a lower level of total cholesterol, E3 had intermediate levels, and E4 had a higher level. Moreover, those with the Apo E4 genotype had a significantly higher level of LDL cholesterol compared to E2 or E3 genotypes. There was no significant difference in mean serum adjusted HDL-cholesterol levels between the three Apo E genotypes.

CONCLUSION

These findings suggest that healthy Irish adults with the Apo E4 genotype have higher serum total and LDL-cholesterol levels than those with E2 or E3 Apo E genotypes and therefore may have a higher risk of atherosclerotic coronary artery disease and coronary heart disease in later life.

Apolipoprotein E and atherosclerosis: insight from animal and human studies

Major advances have been made in our understanding of the role of apolipoprotein E (apoE) in the onset and development of atherosclerosis. Increasing evidence from both animal and human studies suggests that apoE is able to protect against atherosclerosis by: a) promoting efficient uptake of triglyceride-rich lipoproteins from the circulation; b) maintaining normal macrophage lipid homeostasis; c) playing a role in cellular cholesterol efflux and reverse cholesterol transport; d) acting as an antioxidant; e) inhibiting platelet aggregation; and f) modulating immune function. In humans, apoE is polymorphic, and this genetic variation has a strong effect on its antiatherogenic characteristics. Thus, compared to the epsilon3 allele, the epsilon4 allele promotes atherosclerosis, whereas the epsilon2 allele is either pro- or anti-atherogenic, depending on the influence of both environmental and genetic factors. ApoE and its gene are prime targets for therapeutic intervention aimed at preventing or treating atherosclerotic vascular disease.

Influence of apolipoprotein E polymorphism on serum lipids and lipoprotein changes from childhood to adulthood: the Bogalusa Heart Study

The influence of apolipoprotein (apo) E polymorphism on serum lipoproteins from childhood to adulthood was examined in 1520 individuals, aged 5-14 years at baseline, followed over a 16-year period. At both times, the e2 allele associated with lower LDL cholesterol (P < 0.001) and higher HDL cholesterol (P < 0.05-0.01), the e4 allele with higher LDL cholesterol (P < 0.001). The e2 allele lowered the adulthood LDL cholesterol level to a greater extent than the childhood level (P < 0.05). With respect to tracking, at the lowest quartile of LDL cholesterol distribution, the persistence in ranks over time was higher in the apoE2 group with E2/3 and E2/2 phenotypes compared with the apoE3 group with E3/3 phenotype and the apoE4 group with E3/4 and E4/4 phenotypes (P = 0.001). Longitudinal increases in the ponderal index (weight/height3) lowered the adulthood HDL cholesterol to a larger extent in e2 carriers (P = 0.017). The interindividual variability in LDL cholesterol due to childhood and adulthood ponderal index was 1.8- to 2.3-fold greater in the apoE2 group versus the apoE3 group. Likewise, cigarette smoking, alcohol use and oral contraceptive use in adulthood explained greater variability in triglycerides (5.3-fold), VLDL cholesterol (7.8-fold) and HDL cholesterol (2.9-fold) in the apoE2 group versus the apoE3 group. Thus, the apoE locus influences not only the levels and tracking of certain lipoproteins from childhood to adulthood but also modulates the association between lifestyle-related factors and lipoproteins.

The apolipoprotein E4 allele is not associated with an abnormal lipid profile in a Native American population following its traditional lifestyle

The apolipoprotein E4 allele is associated in industrialized countries with an elevated LDL cholesterol concentration and an increased cardiovascular risk. Our purpose in this study was to assess the influence of the genetic variation at the APOE gene locus on the lipid profile of a Native American rural population. We examined plasma lipid levels and the common apo E alleles in 142 healthy randomly selected adults living in their native communities in western Mexico. Their age was 38+/-17 years and the BMI 25.7+/-4.5 kg/m2. Plasma cholesterol, triglycerides, LDL C and HDL C were 165+/-29.6, 126+/-83, 98+/-26 and 42+/-12.7 mg/dl respectively. Ninety-one per cent of the subjects had Lp(a) concentrations below 20 mg/dl and 30% had levels lower than 2 mg/dl. The most common APOE genotype was E3/3 (63%), followed by E3/4 (30.1%). The prevalence of the E2 allele was very low (2.3%). No difference was observed in LDL C concentrations between the E3/E3 and E3/E4 subjects; however carriers of the E2/3 genotype had lower LDL C levels. Similar results were obtained for cholesterol and apo B levels. In summary, the increased LDL C levels associated with the E4 allele in previous studies were not observed in a population with non-westernized habits. Environmental factors, such as diet and lifestyle, could outweigh the hypercholesterolemic predisposition resulting from the presence of the apo E4 allele.

Association of apolipoprotein E polymorphism and concentration with serum lipids and apolipoprotein level in the Chinese from Shanghai

The influence of apolipoprotein E polymorphism and apoE level on serum lipids and apolipoproteins was investigated in 71 healthy people and 43 patients with coronary artery disease from Shanghai. The frequency of apoE alleles was 0.06 for epsilon2, 0.86 for epsilon3, and 0.07 for epsilon4 in the healthy group, and 0.14 for epsilon2, 0.77 for epsilon3, and 0.09 for epsilon4 in the coronary artery disease group. There was no significant difference in the frequency of apoE alleles between these two groups. Serum levels of triglyceride and apo AI did not differ according to apoE genotypes, whereas serum level of apoB was significantly different according to apoE genotypes (p<0.05) both in healthy and coronary artery disease groups. However, in the healthy group, apo epsilon2 allele carriers had significantly higher level of apoE than apo epsilon3 and epsilon4 allele carriers (p<0.001) and apo epsilon4 allele carriers had significantly higher level of total cholesterol than apo epsilon3 and epsilon2 allele carriers. These were not observed in the coronary artery disease group. ApoE concentration was positively correlated with cholesterol, apoAI, and apoB levels in the control subjects and no significant correlation was observed with triglyceride level. In contrast, apoE level was positively related only to triglyceride level in the coronary artery disease group. In the control group, apoE genotypes and apoE level explained together 19.3% and 26.6% of the variability of apoB and cholesterol level, respectively, apoE polymorphism explained 23% of the variability of apoE level and apoE level explained 13.2% of the variability of apoAI level. In the coronary artery disease group, only apoE level explained 41.7% of triglyceride variability. Finally we compared our results with those previously obtained in a French healthy population, the Stanislas cohort. Results suggested that there were some difference between the Chinese control and the French subjects.

Lipid profiles reflecting high and low risk for coronary heart disease: contribution of apolipoprotein E polymorphism and lifestyle

To elucidate the role of modifiable factors and the apolipoprotein E polymorphism in explaining lipid profiles reflecting low, average and high risk for coronary heart disease, we selected subjects from a large population-based study. Subjects with low total cholesterol (TC) (< 15th percentile) and high HDL-cholesterol levels (> 85th percentile) were randomly selected (n = 99) and represent subjects with a low risk lipid profile. Additionally, 95 subjects with total and HDL-cholesterol levels in the 15% around the population-median (median risk lipid profile) and 100 subjects with high TC (> 85th percentile) and low HDL-cholesterol levels (< 15th percentile) (high risk lipid profile) were selected. Compared with E3/3 subjects, the likelihood for a low risk lipid profile was considerably higher (odds ratio 14.3; 2.6-79) in female, but not in male E2-carriers (1.5; 0.3-6.7). Smoking and alcohol consumption were independently associated with a low risk lipid profile in both genders, physical inactivity only in women. The odds ratio for a high risk lipid profile was elevated in male E4-carriers (4.9; 1.1-23) only. In addition to the E4 isoform, smoking and physical inactivity, overweight was the main determinant for a high risk lipid profile (odds ratio 16.8; 3.4-82). Male overweight E4-carriers had a 50 times higher likelihood of a high risk lipid profile than E3/3 men of normal weight. In women, only overweight was independently associated with a high risk lipid profile. Our results suggest that both modifiable factors and the apolipoprotein E polymorphism contribute to a lipid profile, reflecting low, average and high risk for coronary heart disease, but effects may be gender-specific.