Familial aggregation of coronary heart disease and its relation to known genetic risk factors

Research Progress and Clinical Translation Potential of Coronary Atherosclerosis Diagnostic Markers from a Genomic Perspective

Objective: Coronary atherosclerosis (CAD) is characterized by arterial intima lipid deposition, chronic inflammation, and fibrous tissue proliferation, leading to arterial wall thickening and lumen narrowing. As the primary cause of coronary heart disease and acute coronary syndrome, CAD significantly impacts global health. Recent genetic studies have demonstrated CAD's polygenic and multifactorial nature, providing molecular insights for early diagnosis and risk assessment. This review analyzes recent advances in CAD-related genetic markers and evaluates their diagnostic potential, focusing on their applications in diagnosis and risk stratification within precision medicine. Methods: We conducted a systematic review of CAD genomic studies from PubMed and Web of Science databases, analyzing findings from genome-wide association studies (GWASs), gene sequencing, transcriptomics, and epigenomics research. Results: GWASs and sequencing studies have identified key genetic variations associated with CAD, including JCAD/KIAA1462, GUCY1A3, PCSK9, and SORT1, which regulate inflammation, lipid metabolism, and vascular function. Transcriptomic and epigenomic analyses have revealed disease-specific gene expression patterns, DNA methylation signatures, and regulatory non-coding RNAs (miRNAs and lncRNAs), providing new approaches for early detection. Conclusions: While genetic marker research in CAD has advanced significantly, clinical implementation faces challenges including marker dynamics, a lack of standardization, and integration with conventional diagnostics. Future research should prioritize developing standardized guidelines, conducting large-scale prospective studies, and enhancing multi-omics data integration to advance genomic diagnostics in CAD, ultimately improving patient outcomes through precision medicine.

The Risk Factors of Acute Coronary Syndrome in Young Women: A Systematic Review and Meta-Analysis

BACKGROUND

Acute coronary syndrome (ACS) has been one of the leading causes of mortality in the world. Despite common understanding regarding ACS as an older population's or man's disease, the number of young women affected by this condition is increasing. Many studies have assessed the risk factors of ACS, but only a few studies focused on this subpopulation. Therefore, this systematic review and meta-analysis aim to evaluate the risk factors predisposing to ACS in the young women population.

METHODS

Nine online databases were screened from the date of inception to September 2021, where the acquired studies were evaluated using the PRISMA statement. The inclusion criteria were a case control study with women age cut-off of <50 years. The risk factors of acute coronary syndrome were analyzed using a random-effect model, expressed as summary statistics of odds ratio (OR) for categorical variable and standard mean difference (SMD) for continuous data with normal distribution, with 95% confidence interval (CI). Quality assessment was conducted using the STROBE statement.

RESULTS

Seven studies with the total of 7042 patients met the inclusion criteria of this metaanalysis. Diabetes mellitus, high BMI, obesity, hypercholestrolemia, hypertension, smoking, and family history significantly increased acute coronary syndrome risk in young women. Other risks such as heavy alcohol consumption, oral contraceptive use, and postmenopausal state were associated with higher risk of ACS.

CONCLUSION

The independent risk factors which are strongly related to ACS in young women were diabetes mellitus, hypertension, and hypercholesterolemia with odd ratios of 6.21, 5.32, and 4.07. Other risk factors which may be associated with an increased risk of ACS in young women were heavy alcohol consumption, oral contraceptive use, and postmenopausal state. Health promotion and effective intervention on this specific population regarding these risk factors can decrease young female cardiovascular morbidity and mortality as well as improved quality of life of women.

Monogenic and Polygenic Models of Coronary Artery Disease

PURPOSE OF THE REVIEW

Coronary artery disease (CAD) is a common disease globally attributable to the interplay of complex genetic and lifestyle factors. Here, we review how genomic sequencing advances have broadened the fundamental understanding of the monogenic and polygenic contributions to CAD and how these insights can be utilized, in part by creating polygenic risk estimates, for improved disease risk stratification at the individual patient level.

RECENT FINDINGS

Initial studies linking premature CAD with rare familial cases of elevated blood lipids highlighted high-risk monogenic contributions, predominantly presenting as familial hypercholesterolemia (FH). More commonly CAD genetic risk is a function of multiple, higher frequency variants each imparting lower magnitude of risk, which can be combined to form polygenic risk scores (PRS) conveying significant risk to individuals at the extremes. However, gaps remain in clinical validation of PRSs, most notably in non-European populations. With improved and more broadly utilized genomic sequencing technologies, the genetic underpinnings of coronary artery disease are being unraveled. As a result, polygenic risk estimation is poised to become a widely used and powerful tool in the clinical setting. While the use of PRSs to augment current clinical risk stratification for optimization of cardiovascular disease risk by lifestyle change or therapeutic targeting is promising, we await adequately powered, prospective studies, demonstrating the clinical utility of polygenic risk estimation in practice.

The Impact of Kidney Development on the Life Course: A Consensus Document for Action

Hypertension and chronic kidney disease (CKD) have a significant impact on global morbidity and mortality. The Low Birth Weight and Nephron Number Working Group has prepared a consensus document aimed to address the relatively neglected issue for the developmental programming of hypertension and CKD. It emerged from a workshop held on April 2, 2016, including eminent internationally recognized experts in the field of obstetrics, neonatology, and nephrology. Through multidisciplinary engagement, the goal of the workshop was to highlight the association between fetal and childhood development and an increased risk of adult diseases, focusing on hypertension and CKD, and to suggest possible practical solutions for the future. The recommendations for action of the consensus workshop are the results of combined clinical experience, shared research expertise, and a review of the literature. They highlight the need to act early to prevent CKD and other related noncommunicable diseases later in life by reducing low birth weight, small for gestational age, prematurity, and low nephron numbers at birth through coordinated interventions. Meeting the current unmet needs would help to define the most cost-effective strategies and to optimize interventions to limit or interrupt the developmental programming cycle of CKD later in life, especially in the poorest part of the world.

Detecting Familial Aggregation

In addition to characterizing the distribution of genetic features of populations (mutation and allele frequencies; measures of Hardy-Weinberg equilibrium), genetic epidemiology and statistical genetics aim to explore and define the role of genomic variation in risk of disease or variation in traits of interest. To facilitate this kind of exploration, genetic epidemiology and statistical genetics address a series of questions: 1. Does the disease tend to cluster in families more than expected by chance alone? 2. Does the disease appear to follow a particular genetic model of transmission in families? 3. Does variation at a particular genomic position tend to cosegregate with disease in families? 4. Do specific genetic variants tend to be carried more frequently by those with disease than by those without these variants in a given population (or across families)? The first question can be examined using studies of familial aggregation or correlation. An ancillary question: "how much of the susceptibility to disease (or variation in disease-related traits) might be accounted for by genetic factors?" is typically answered by estimating heritability, the proportion of variance in a trait or in risk to a disease attributable to genetics. The second question can be formally tested using pedigrees for which disease affection status or trait values are available through a modeling approach known as segregation analysis. The third question can be answered with data on genomic markers in pedigrees with affected members informative for linkage, where meiotic cross-over events are estimated or assessed. The fourth question is answerable using genotype data on genomic markers on unrelated affected and unaffected individuals and/or families with affected members and unaffected members. All of these questions can also be explored for quantitative (or continuously distributed) traits by examining variation in trait values between family members or between unrelated individuals. While each of these questions and the analytical approaches for answering them is explored extensively in subsequent chapters (heritability in Chapters 8 and 9 ; segregation in Chapter 12 ; linkage in Chapters 13 - 17 ; and association in Chapters 18 - 20 ), this chapter focuses on statistical methods to address questions of familial aggregation of qualitative phenotypes (e.g., disease status) or quantitative phenotypes.While studies exploring genotype-phenotype correlations are arguably the most important and common type of statistical genetic study performed, these studies are performed under the assumption that genetic contributors at least partially explain risk of a disease or a trait of interest. This may not always be the case, especially with diseases or traits known to be strongly influenced by environmental factors. For this reason, before any of the last three questions described above can be answered, it is important to ask first whether the disease clusters among family members more than unrelated persons, as this constitutes evidence of a possible heritable contribution to disease, justifying the pursuit of studies answering the other questions. In this chapter, the underlying principles of familial aggregation studies are addressed to provide an understanding and set of analytical tools to help answer the question if diseases or traits of interest are likely to be heritable and therefore justify subsequent statistical genetic studies to identify specific genetic causes.

Familial Factors, Low Birth Weight, and Development of ESRD: A Nationwide Registry Study

BACKGROUND

Previous studies have demonstrated that low birth weight (LBW) is associated with higher risk for end-stage renal disease (ESRD). However, both LBW and ESRD cluster in families. The present study investigates whether familial factors explain the association between LBW and ESRD.

STUDY DESIGN

Retrospective registry-based cohort study.

SETTING & PARTICIPANTS

Since 1967, the Medical Birth Registry of Norway has recorded medical data for all births in the country. Sibling data are available through the Norwegian Population Registry. Since 1980, all patients with ESRD in Norway have been registered in the Norwegian Renal Registry. Individuals registered in the Medical Birth Registry with at least 1 registered sibling were included.

PREDICTOR

LBW in the participant and/or LBW in at least 1 sibling.

OUTCOME

ESRD.

RESULTS

Of 1,852,080 included individuals, 527 developed ESRD. Compared with individuals without LBW and with no siblings with LBW, individuals without LBW but with a sibling with LBW had an HR for ESRD of 1.20 (95% CI, 0.91-1.59), individuals with LBW but no siblings with LBW had an HR of 1.59 (95% CI, 1.18-2.14), and individuals with LBW and a sibling with LBW had an HR of 1.78 (95% CI, 1.26-2.53). Similar results were observed for individuals who were small for gestational age (SGA). Separate analyses for the association of age 18 to 42 years and noncongenital ESRD showed stronger associations for SGA than for LBW, and the associations were not statistically significant for age 18 to 42 years for LBW.

LIMITATIONS

Follow-up only until 42 years of age.

CONCLUSIONS

LBW and SGA are associated with higher risk for ESRD during the first 40 years of life, and the associations were not explained by familial factors. Our results support the hypothesis that impaired intrauterine nephron development may be a causal risk factor for progressive kidney disease.

The relation between the presence of cardiovascular disease and vascular risk factors in offspring and the occurrence of new vascular events in their parents already at high vascular risk

BACKGROUND

For parents at high risk for cardiovascular events, presence of cardiovascular disease or risk factors in their offspring may be an indicator of their genetic load or exposure to (unknown) risk factors and might be related to the development of new or recurrent vascular events.

METHODS

In 4,267 patients with vascular disease, hypertension, diabetes, or hypercholesterolemia enrolled in the SMART cohort, the presence of cardiovascular risk factors (hypertension, diabetes, hypercholesterolemia, smoking, or overweight) and cardiovascular disease (coronary artery disease, cerebrovascular disease, peripheral artery disease, or abdominal aortic aneurysm) was assessed in their 10,564 children. The relation between presence of cardiovascular disease or cardiovascular risk factors in their offspring and new or recurrent vascular events was determined by Cox proportional hazard analyses.

RESULTS

Of the patients, 506 (12%) had offspring with cardiovascular disease, hypertension, hypercholesterolemia, or diabetes. Smoking in offspring was present in 1,972 patients (46%), and overweight in 845 patients (20%). During a median follow-up of 7.0 years (interquartile range 3.7-10.4), the composite outcome of myocardial infarction (MI), stroke, or vascular mortality occurred in 251 patients. Patients with offspring with cardiovascular disease, hypertension, hypercholesterolemia, or diabetes had an increased risk of vascular mortality (hazard ratio [HR] 2.9, 95% CI 1.2-7.1), MI (HR 1.6, 95% CI 1.1-2.5), and the composite outcome (HR 1.5, 95% CI 1.1-2.2). Diabetes in offspring was related to an increased risk of the composite outcome (HR 2.7, 95% CI 1.5-5.0), MI (HR 3.3, 95% CI 1.7-6.6), and vascular mortality (HR 3.4, 95% CI 0.8-14.8). Smoking and overweight in offspring were not related to increased vascular risk in parents.

CONCLUSIONS

Presence of cardiovascular disease, hypertension, hypercholesterolemia, and diabetes in offspring, with diabetes mellitus being the most contributing cardiovascular risk factor, is related to an increased risk of developing new or subsequent vascular events in patients already at high vascular risk.

KALRN Rare and Common Variants and Susceptibility to Ischemic Stroke in Chinese Han Population

Stroke is the second most common cause of mortality worldwide, and it is a major cause of physical disability. Several genome-wide association studies have yielded numerous common variants which increase the risk of ischemic stroke, including the Kalirin-coding gene, KALRN. KALRN strongly associates with early-onset coronary artery disease and atherosclerosis and plays an important role in stroke in the European population. In this study, we analyzed four KALRN gene SNPs in 503 ischemic stroke patients and 493 control subjects, separating the patients into separate research groups based on comorbidity with hypertension or diabetes and stroke type (atherosis or lacunar and combination type). We found a rare variant of KALRN, rs11712619, that associated with lacunar stroke in the northern Chinese Han population with an average-risk allele frequency 0.009 (OR 2.95, 95 % CI 1.08-8.01, p = 0.028). However, after adjusting for relevant factors, including sex, age, body mass index, dyslipidemia, alcohol consumption, and smoking, this association was not evident. Additionally, the KALRN variant rs6438833 was associated with ischemic stroke, ischemic stroke comorbid with diabetes, and lacunar stroke after adjusting for the relevant factors (p = 0.046, p = 0.019 and p = 0.046, respectively), which remained significant after 10,000 permutation procedure test (p' = 0.047, p' = 0.018 and p' = 0.048, respectively). The association of these rare and common variants of KALRN with ischemic stroke in northern Chinese Han population offers insight for potential therapeutic research.

Should your family history of coronary heart disease scare you?

Traditional risk factors explain most of the risk associated with coronary heart disease, and after adjustment for risk factors family history was believed to contribute very little to population-attributable risk of coronary heart disease. However, the INTERHEART study demonstrated an independent association of family history of coronary heart disease with acute myocardial infarction. To assess this relationship more comprehensively in multiple datasets in different populations, we carried out a detailed review of the available evidence. Case-control studies involving 17,202 cases and 30,088 controls yielded a pooled unadjusted odds ratio (random-effects model, overall I(2) = 64.6%, P = 0.000) of 2.03 (95% confidence interval: 1.79-2.30), whereas cohort studies that included 313,837 individuals yielded an unadjusted relative risk for future coronary heart disease (random-effects model, overall I(2) = 88.7%, P = 0.000) of 1.60 (95% confidence interval: 1.44-1.77). Although the presence of family history of coronary heart disease indicates a cumulative exposure of shared genes and environment, the risk estimates for family history did not attenuate significantly after adjustment for conventional coronary heart disease risk factors in several studies. It is probably an oversimplification to dichotomize the family history variable into a simple "yes" or "no" risk factor, as the significance of family history is influenced by several variables, such as age, sex, number of relatives, and age at onset of disease in the relatives. Moreover, a quantitative risk-assessment model for the family history variable, such as the "family risk score," has a positive linear relationship with coronary heart disease. More studies are warranted to assess the benefits and risks of intensive interventions, both targeted individually and at the family level, among individuals with a valid family history and borderline elevated risk factors.

Detecting familial aggregation

Beyond calculating parameter estimates to characterize the distribution of genetic features of populations (frequencies of mutations in various regions of the genome, allele frequencies, measures of Hardy-Weinberg disequilibrium), genetic epidemiology aims to identify correlations between genetic variants and phenotypic traits, with considerable emphasis placed on finding genetic variants that increase susceptibility to disease and disease-related traits. However, determining correlation alone does not suffice: genetic variants common in an isolated ethnic group with a high burden of a given disease may show relatively high correlation with disease but, as markers of ethnicity, these may not necessarily have any functional role in disease. To establish a causal relationship between genetic variants and disease (or disease-related traits), proper statistical analyses of human data must incorporate epidemiologic approaches to examining sets of families or unrelated individuals with information available on individuals' disease status or related traits.Through different analytical approaches, statistical analysis of human data can answer several important questions about the relationship between genes and disease: 1. Does the disease tend to cluster in families more than expected by chance alone? 2. Does the disease appear to follow a particular genetic model of transmission in families? 3. Do variants at a particular genetic marker tend to cosegregate with disease in families? 4. Do specific genetic markers tend to be carried more frequently by those with disease than by those without, in a given population (or across families)? The first question can be examined using studies of familial aggregation or correlation. An ancillary question: "how much of the susceptibility to disease (or variation in disease-related traits) might be accounted for by genetic factors?" is typically answered by estimating heritability, the proportion of disease susceptibility or trait variation attributable to genetics. The second question can be formally tested using pedigrees for which disease affection status or trait values are available through a modeling approach known as segregation analysis. The third question can be answered with data on pedigrees with affected members and genotype information at markers of interest, using linkage analysis. The fourth question is answerable using genotype information at markers on unrelated affected and unaffected individuals and/or families with affected and unaffected members. All of these questions can also be explored for quantitative (or continuously distributed) traits by examining variation in trait values between family members or between unrelated individuals. While each of these questions and the analytical approaches for answering them is explored extensively in subsequent chapters (heritability in Chapters 9 and 10, segregation in Chapter 12, linkage in Chapters 13-17, and association in Chapters 18-21 and 23), this chapter focuses on statistical methods to answer questions of familial aggregation.

The role of common variants of the cholesteryl ester transfer protein gene in left main coronary artery disease

BACKGROUND

The cholesteryl ester transfer protein (CETP) has a central role in the lipid metabolism and therefore may alter the susceptibility to atherosclerosis.

METHODS

The DNA of 471 subjects [133 subjects with angiographically documented left main coronary artery disease (LMCAD), 241 subjects with more peripheral coronary artery disease (MPCAD) and 97 subjects self reported healthy (Controls)] was analyzed for the frequency of TaqIB and I405V polymorphisms in the gene coding CETP.

RESULTS

There is no significant difference in CETP allele frequency or genotype distribution among LMCAD and MPCAD patients although there is statistical difference between LMCAD and Controls (p = 0.001). Specifically, patients with LMCAD and B1B1 genotype of TaqIB polymorphism were more frequent present compared to Controls (33.8% vs 22.9%, respectively). The frequency of B2B2 genotype was 3 times lower in the LMCAD group compared to Controls (10.5% vs 30.2%, respectively). In the LMCAD group the frequency of B1 allele compared to Controls was higher (62% vs 46%, respectively, p = 0.001). The relationship between TaqIB gene polymorphism and the LMCAD was independent of lipid profile, with the exception of apolipoprotein A.

CONCLUSIONS

These findings indicate that the TaqIB polymorphism may have potential importance in screening individuals at high risk for developing CAD. However, this polymorphism cannot distinguish between LMCAD and MPCAD. Further prospective investigations in larger populations are required to confirm these findings.

Sibling history of myocardial infarction or stroke and risk of cardiovascular disease in the elderly: the Cardiovascular Health Study

PURPOSE

To assess the relationship between sibling history of myocardial infarction (MI) or stroke with cardiovascular disease (CVD) and risk factors in older adults.

METHODS

Prospective cohort study of 5,888 older adults participating in the Cardiovascular Health Study (CHS). History of MI and stroke in siblings was obtained by self-report. Participants with positive sibling histories were compared to those with negative histories to determine if prevalent or incident disease (coronary heart disease [CHD], MI, stroke, angina), subclinical CVD (carotid wall thickness, left ventricular mass, hypertension, diabetes, ankle-brachial index), CVD risk factors differed between groups.

RESULTS

More than 91% (n = 5,383) of CHS participants reported at least one sibling. Sibling history of MI was associated with increased disease prevalence (CHD, MI, angina) and incidence (CHD, angina). Sibling history of stroke was associated with increased disease prevalence (CHD, angina). Sibling history of either MI or stroke was associated with increased disease prevalence and incidence for CHD, MI and angina, more subclinical disease, and a higher CVD risk profile.

CONCLUSIONS

Sibling history of MI and stroke were markers of higher CVD risk status even in older adults. Of clinical importance, participants with positive sibling history have numerous risk factors amenable to intervention.

The transcription factor GATA-2 does not associate with angiographic coronary artery disease in the Ottawa Heart Genomics and Cleveland Clinic GeneBank Studies

The transcription factor GATA2 was reported to associate with coronary artery disease (CAD) in the family-based Genecard sample (Connelly et al. in PLoS Genet 2:e139, 2006). We asked whether GATA2 associates with sporadic cases of CAD in the Ottawa Heart Genomics Study (OHGS) and Cleveland Clinic (CC) populations. We genotyped the lead single nucleotide polymorphism (SNP) from Genecard, rs2713604 which is located in intron 5-6 of GATA2 in 600 CAD cases and 625 controls, as well as a tag SNP rs1573949 (r (2) = 0.87 in Caucasians of European ancestry in Utah from HapMap) in 1,136 cases and 1,162 controls in the OHGS1 population. A further 1,838 CAD cases and 913 controls derived from an independent sample combining genotypes from CC and OHGS2 populations were genotyped for rs1573949. Neither of the genotyped SNPs associates with CAD in the OHGS1 or CC/OHGS2 populations. Our data suggest that GATA2 does not contribute to the development of angiographic CAD among sporadic cases.

A customized genetic approach to the number one killer: coronary artery disease

PURPOSE OF REVIEW

To review the evidence supporting genetic predisposition to coronary artery disease (CAD). Secondly, to elucidate the barriers precluding the identification of genes responsible for CAD. Thirdly, to indicate the new technology now available to overcome these barriers and summarize current progress.

RECENT FINDINGS

Evidence strongly supports that 50% of susceptibility to CAD is genetic. Prevention of CAD requires comprehensive genetic and risk factor modification. Technology to perform genome-wide association studies became available in 2005, namely, the microarrays with 500,000 and 1 million single nucleotide polymorphisms as DNA markers for high-throughput genotyping to determine gene frequencies in large datasets of cases and controls. The first genetic variant, 9p21, for CAD was identified in the Ottawa Heart Genomic study. This is not only a genetic risk factor but also independent of other known risk factors for CAD. 9p21 was subsequently confirmed as a risk variant in several other independent studies involving 64 000 Caucasians. 9p21 increases the risk of CAD by 40% and 20% in heterozygous or homozygous forms respectively. It occurs in 75% of Caucasians, and has recently been confirmed in several other ethnic groups.

SUMMARY

Thus, identification of predisposition to CAD is well underway with genome-wide association studies and the first common genetic risk variant, 9p21, has been identified.

Polymorphisms of the tumor suppressor gene LSAMP are associated with left main coronary artery disease

Previous association mapping on chromosome 3q13-21 detected evidence for association at the limbic system-associated membrane protein (LSAMP) gene in individuals with late-onset coronary artery disease (CAD). LSAMP has never been implicated in the pathogenesis of CAD. We sought to thoroughly characterize the association and the gene. Non-redundant single nucleotide polymorphisms (SNPs) across the gene were examined in an initial dataset (168 cases with late-onset CAD, 149 controls). Stratification analysis on left main CAD (N = 102) revealed stronger association, which was further validated in a validation dataset (141 cases with left main CAD, 215 controls), a third control dataset (N = 255), and a family-based dataset (N = 2954). A haplotype residing in a novel alternative transcript of the LSAMP gene was significant in all independent case-control datasets (p = 0.0001 to 0.0205) and highly significant in the joint analysis (p = 0.00004). Lower expression of the novel alternative transcript was associated with the risk haplotype (p = 0.0002) and atherosclerosis burden in human aortas (p = 0.0001). Furthermore, silencing LSAMP expression in human aortic smooth muscle cells (SMCs) substantially augmented SMC proliferation (p<0.01). Therefore, the risk conferred by the LSAMP haplotype appears to be mediated by LSAMP down-regulation, which may promote SMC proliferation in the arterial wall and progression of atherosclerosis.

Identifying genes for coronary artery disease: An idea whose time has come

BACKGROUND

Coronary artery disease (CAD) remains the number one killer in the western world. Genetics accounts for greater than 50% of the risk for CAD. Genetic screening and early prevention in individuals identified as being at increased risk could dramatically reduce the prevalence of CAD, thus necessitating the identification of genes predisposing to CAD. Studies of genes identified by the candidate gene approach have not been replicated due, in part, to inadequate sample size. Genome-wide scan association studies have been limited by the use of thousands of markers rather than the hundreds of thousands required, and by the use of hundreds of individuals rather than the thousands required. Replication of positive findings in an independent population is essential. To detect a minor allele frequency of 5% or greater with an odds ratio for risk of 1.3 or greater and 90% power, an estimated 14,000 (9000 affected and 5000 control) subjects are required.

METHODS

The Affymetrix GeneChip Human Mapping 500K Array Set (Affymetrix Inc, USA) provides a marker every 6000 base pairs as required, and is being used to genotype 1000 cases of premature CAD and 1000 normal subjects, followed by replication in 8000 affected individuals and 4000 control subjects. The phenotype is confirmed or excluded by coronary arteriograms by catheterization or multislice computed tomography.

RESULTS

Since 2005, more than 800 million genotypes have been performed and analyses performed on 500 control subjects and 500 affected individuals. Several thousand significant single nucleotide polymorphisms and 130 clusters associated with CAD have been identified.

CONCLUSIONS

This is the first genome-wide scan using the 500,000 marker set in a case-control association study for CAD genes. Several genes associated with CAD appear promising.

Familial premature coronary artery disease mortality and obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is linked to both coronary artery disease (CAD) and sudden death, but any causal role remains unclear. A family history of premature CAD and related mortality is an independent risk factor for the development of CAD. We hypothesized that OSA is associated with a family history of premature mortality from ischemic heart disease.

METHODS

We prospectively studied 588 subjects who underwent polysomnography from May 2000 to June 2004. Demographics, comorbidities, family history of cardiovascular disease, and the ages and causes of death for 10 strata of family members were recorded for all subjects. We excluded those subjects with known causes of premature cardiac death, such as hypertrophic cardiomyopathy and long-QT syndrome. OSA was defined by American Academy of Sleep Medicine criteria (ie, apnea-hypopnea index >or= 5). Premature CAD mortality was defined as death due to ischemic heart disease or sudden cardiac death before 55 years of age (men) or 65 years of age (women).

RESULTS

Polysomnography confirmed OSA in 316 subjects and excluded it in 202 subjects. The unadjusted odds ratio (OR) for OSA and a family history of premature CAD mortality was 2.11 (95% confidence interval [CI], 1.10 to 4.31; p = 0.031). After adjusting for each subject's sex, body mass index, and history of CAD, there was a significant and independent association between OSA and family history of premature CAD mortality (OR, 2.13; 95% CI, 1.04 to 4.66; p = 0.046).

CONCLUSIONS

Regardless of their own CAD status, people with OSA are more likely than those without OSA to have a family history of premature CAD mortality.

Families of patients with premature coronary heart disease: an obvious but neglected target for primary prevention

Risk of premature coronary heart disease is increased in the families of affected patients. C K Chow and colleagues argue that targeting relatives for primary prevention would be an effective policy

Polymorphisms in the paraoxonase and endothelial nitric oxide synthase genes and the risk of early-onset myocardial infarction

In young patients, the accumulative burden of traditional cardiovascular risk factors may not be as significant as in an older population. Genetic risk factors were suggested to have a role in the early development of myocardial infarction (MI). However, data about the association between polymorphisms in heart disease-related genes and the early onset of a first MI are limited. In the present study, age at onset of a first MI was related to individual single-nucleotide polymorphisms in each of 18 prespecified candidate genes in a cohort of 814 patients enrolled in the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) Study. Multivariate regression analysis showed in patients who had the high-risk genotypes of paraoxonase 1 (PON1) Q192R and endothelial nitric oxide synthase (eNOS) E298D that ages at onset of a first MI were 1.8 (p = 0.02) and 3.5 years (p = 0.02) earlier than in noncarriers of the genotypes, respectively. Consistently, high-risk genotypes of the PON1 Q192R and eNOS E298D polymorphisms were significantly associated with onset of a first MI at age <50 years (adjusted odds ratio 1.70, p = 0.005, adjusted odds ratio 2.15, p = 0.01, respectively). In conclusion, our findings suggest that high-risk genotypes of the PON1 Q192R and eNOS E298D polymorphisms are independently associated with a significantly earlier occurrence of coronary events.

Peakwide mapping on chromosome 3q13 identifies the kalirin gene as a novel candidate gene for coronary artery disease

A susceptibility locus for coronary artery disease (CAD) has been mapped to chromosome 3q13-21 in a linkage study of early-onset CAD. We completed an association-mapping study across the 1-LOD-unit-down supporting interval, using two independent white case-control data sets (CATHGEN, initial and validation) to evaluate association under the peak. Single-nucleotide polymorphisms (SNPs) evenly spaced at 100-kb intervals were screened in the initial data set (N=468). Promising SNPs (P<.1) were then examined in the validation data set (N=514). Significant findings (P<.05) in the combined initial and validation data sets were further evaluated in multiple independent data sets, including a family-based data set (N=2,954), an African American case-control data set (N=190), and an additional white control data set (N=255). The association between genotype and aortic atherosclerosis was examined in 145 human aortas. The peakwide survey found evidence of association in SNPs from multiple genes. The strongest associations were found in three SNPs from the kalirin (KALRN) gene, especially in patients with early-onset CAD (P=.00001-00028 in the combined CATHGEN data sets). In-depth investigation of the gene found that an intronic SNP, rs9289231, was associated with early-onset CAD in all white data sets examined (P<.05). In the joint analysis of all white early-onset CAD cases (N=332) and controls (N=546), rs9289231 was highly significant (P=.00008), with an odds-ratio estimate of 2.1. Furthermore, the risk allele of this SNP was associated with atherosclerosis burden (P=.03) in 145 human aortas. KALRN is a protein with many functions, including the inhibition of inducible nitric oxide synthase and guanine-exchange-factor activity. KALRN and two other associated genes identified in this study (CDGAP and MYLK) belong to the Rho GTPase-signaling pathway. Our data suggest the importance of the KALRN gene and the Rho GTPase-signaling pathway in the pathogenesis of CAD.

Personalized genomic medicine: a future prerequisite for the prevention of coronary artery disease

Within the next 10-15 years, medicine will be personalized in large part on the basis of the individual's genomic variants. Coronary artery disease remains the number one cause of morbidity and mortality in the Western world and is predicted to become the number one cause worldwide by 2010. It has been stated that treating the risk factors of coronary artery disease has made it a preventable disease that should be eliminated in the 21st century. It is postulated that about 50% of susceptibility to coronary artery disease is genetic, involving known and occult risk factors. Thus, comprehensive prevention will require identification of genetic susceptibility. The recent technology of a chip with 500,000 DNA markers makes genome-wide scanning to identify the genes contributing to coronary artery disease possible. Multislice CT will provide the high-throughput coronary arteriograms required for this research and for prevention in asymptomatic individuals with a family history of heart disease.

GATA2 is associated with familial early-onset coronary artery disease

The transcription factor GATA2 plays an essential role in the establishment and maintenance of adult hematopoiesis. It is expressed in hematopoietic stem cells, as well as the cells that make up the aortic vasculature, namely aortic endothelial cells and smooth muscle cells. We have shown that GATA2 expression is predictive of location within the thoracic aorta; location is suggested to be a surrogate for disease susceptibility. The GATA2 gene maps beneath the Chromosome 3q linkage peak from our family-based sample set (GENECARD) study of early-onset coronary artery disease. Given these observations, we investigated the relationship of several known and novel polymorphisms within GATA2 to coronary artery disease. We identified five single nucleotide polymorphisms that were significantly associated with early-onset coronary artery disease in GENECARD. These results were validated by identifying significant association of two of these single nucleotide polymorphisms in an independent case-control sample set that was phenotypically similar to the GENECARD families. These observations identify GATA2 as a novel susceptibility gene for coronary artery disease and suggest that the study of this transcription factor and its downstream targets may uncover a regulatory network important for coronary artery disease inheritance.

Coronary artery disease (CAD) is the most common form of heart disease in the Western world and is one of the leading causes of death in the United States. CAD is inherited and is a complex genetic disease because it results from changes to multiple genes acting in concert with one another and the environment. The authors locate CAD susceptibility genes by convergence of techniques and identify variation within a gene of interest in an early-onset CAD population. If a specific variant is found more often in affected individuals or families than in controls, this can suggest that this gene variant is associated with disease. The authors have identified a gene, GATA2, which is located in a genomic region suspected to contain genes for CAD and displays expression patterns predictive of location of disease within human donor aortas. They have identified several GATA2 variants that segregate with CAD in a family-based early-onset CAD population and have further validated two of these associations in a separate young case-control sample affected with CAD. These data imply that the transcription factor GATA2 may play a role in CAD susceptibility and suggest that the study of GATA2 targets may uncover a set of GATA2-regulated genes important to CAD inheritance.

Influence of selected lifestyle factors on risk of acute myocardial infarction in subjects with familial predisposition for the disease

BACKGROUND

The joint effect of family history of acute myocardial infarction (AMI) and selected adult life risk factors on the risk of the disease is not clear.

METHODS

We used the combined data set from three Italian case-control studies including 1737 cases of incident, nonfatal AMI and 2317 hospital controls, aged less than 75 years. An adult lifestyle risk score (ALRS) was computed, including tobacco, body mass index, physical activity, and consumption of coffee, alcohol, fish, and vegetables.

RESULTS

Compared to the reference category (subjects with no family history of AMI and low ALRS), the risk of AMI was 4.97 (95% confidence intervals, CI: 4.00-6.18) in subjects without family history and high ALRS, 2.19 (95% CI: 1.65-2.90) in subjects with family history and low ALRS, and 11.90 (95% CI: 8.94-15.84) in subjects with family history and high ALRS.

CONCLUSIONS

The risk of AMI in subjects with a familial predisposition to ischaemic heart disease might be substantially reduced by intervention on selected lifestyle risk factors for AMI. In absolute terms, any such intervention would be more effective than a comparable one on subjects without a familial predisposition.

Daytime triglyceridemia in normocholesterolemic patients with premature atherosclerosis and in their first-degree relatives

Postprandial hypertriglyceridemia tested under metabolic ward conditions with unphysiological high fat loads has been reported in CAD patients and their relatives even in the presence of normal fasting lipids. It is unclear whether this also occurs in the daytime situation. Twenty-seven normocholesterolemic, non-obese and nondiabetic patients with premature coronary artery disease (CAD) and 56 first-degree relatives without CAD measured daytime capillary triglyceride profiles (TGc-AUC) as an estimate of postprandial lipemia. Fasting capillary triglycerides (TGc) were not significantly different between CAD index patients and their relatives (1.68 +/- 0.63 and 1.54 +/- 0.71 mmol/L, respectively). In contrast, daytime triglyceridemia was significantly higher in CAD patients (30.7 +/- 13.6 mmol. h/L) compared to their relatives (24.4 +/- 9.4 mmol. h/L) and this was also the case after correction for fasting TGc (7.24 +/- 7.41 and 2.79 +/- 6.89 mmol. h/L; P <.05). The best predictors of TGc-AUC by multiple regression analysis in CAD families were fasting TGc, systolic blood pressure, and high-density lipoprotein cholesterol (HDL-C), which are all components of the metabolic syndrome, explaining 65% of the variation. Since there were no major differences in nutritional intake between index patients and their relatives, this could not explain the differences Daytime triglyceridemia, measured under physiological conditions, is increased in patients with premature atherosclerosis and normal fasting TG levels, when compared to their non-CAD relatives. This study confirms previous observations using standardized oral fat loading tests and underlines the importance of postprandial hyperlipidemia in CAD.

Familial Aggregation of Early-Onset Myocardial Infarction

Although ischemic heart disease tends to cluster in families, previous studies have reported a modest (2-fold increased risk) to strong (10-fold increased risk) contribution of family history to the explanation of disease occurrence. The authors assessed the familial aggregation of early-onset myocardial infarction in 11,307 adults aged <65 years who participated in the Third National Health and Nutrition Examination Survey. Logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs). A parental history was more common in those with (n = 237) than in those without (n = 11,070) a myocardial infarction (19.8 vs. 7.9%, p < or = 0.01). Adults with a parental history were also more likely to have multiple risk factors for cardiovascular disease (OR for four or five risk factors compared with none: 2.9, 95% CI: 1.4, 6.3). After multivariate adjustment, the likelihood of myocardial infarction was more than three times greater among adults with a parental history than among those without (95% CI: 1.7, 6.7). A maternal history of myocardial infarction was strongly associated (OR = 6.1, 95% CI: 2.1, 17.4) with an increased likelihood of myocardial infarction, and a paternal history was associated with a 3-fold (95% CI: 1.5, 6.3) increased likelihood of myocardial infarction after adjustment for cardiovascular disease risk factors. These results suggest a familial aggregation of early-onset myocardial infarction and show that family history is strongly associated with cardiovascular disease risk factors.

Cardiovascular risk factors associated with insulin resistance cluster in families with early-onset coronary heart disease

Coronary heart disease (CHD) is a multifactorial disease caused by environmental and genetic factors. CHD clusters in families, but it is not known whether susceptibility to early-onset CHD is associated with the clustering of cardiovascular risk factors. Therefore, we determined the levels of cardiovascular risk factors among siblings with and without severe early-onset CHD drawn from 101 Finnish families. Probands with CHD, compared with their siblings without CHD, had, respectively, higher 2-hour insulin levels (475.7 versus 331.8 pmol/L, P=0.011) and 2-hour insulin areas (796.2 versus 640.4 pmol/L per hour, P=0.031) in an oral glucose tolerance test, lower high density lipoprotein cholesterol levels (1.22 versus 1.42 mmol/L, P=0.001), higher total triglyceride levels (1.91 versus 1.68 mmol/L, P=0.018), higher very low density lipoprotein triglyceride levels (1.25 versus 1.06 mmol/L, P=0.011), and higher fibrinogen levels (3.8 versus 3.4 g/L, P= 0.008). No significant differences were found in cardiovascular risk factors between affected siblings and probands with CHD. Environmental or lifestyle factors did not differ between siblings with or without early-onset CHD. We conclude that cardiovascular risk factors associated with the insulin resistance syndrome (hyperinsulinemia, low high density lipoprotein cholesterol, high total and very low density lipoprotein triglycerides, and high fibrinogen) are likely to contribute indirectly to early-onset CHD.

Genetic predisposition to coronary artery disease

Understanding the genetic basis of coronary artery disease (CAD) can improve management and prevention. Family and twin studies, animal models and gene association studies support a genetic basis for CAD. Genes contribute to CAD development and progression, and response to risk factor modification and lifestyle choices. Family history is the best indicator of a predisposition to CAD and further refinement is possible with biochemical and DNA testing. Many inherited cardiovascular risk factors can be modified, such as LDL cholesterol, homocysteine and lipoprotein(a). Early detection of CAD might lead to earlier intervention for genetically susceptible individuals. However, data are lacking regarding the efficacy of this approach in preventing clinical events. Despite this lack of evidence, knowledge of genetic CAD susceptibility has value in providing risk information and guiding decision making. Further research that investigates outcomes regarding genetic risk assessment for CAD is necessary.

Family risk score of coronary heart disease (CHD) as a predictor of CHD: the Atherosclerosis Risk in Communities (ARIC) study and the NHLBI family heart study

Family history of coronary heart disease (CHD) has been found to be a risk factor for CHD in numerous studies. Few studies have addressed whether a quantitative measure of family history of CHD (family risk score, FRS) predicts CHD in African Americans. This study assessed the association between FRS and incident CHD of participants, and the variation of the association by gender and race. Participants in the study were a biracial population-based cohort with 3,958 African Americans and 10,580 Whites aged 45-64 years old in the ARIC baseline survey (1987-1989). They were randomly selected from four U. S. communities. During follow-up (1987-1993), 352 participants experienced the onset of CHD. Incidence density of CHD (per 1,000 person-years) was 7.8 and 3.6 among African-American men (AAM) and women (AAW), and 7.2 and 2.2 among White men (WM) and women (WW). The hazard rate ratio (HRR) of CHD associated with one standard deviation increase of FRS was 1.52 in AAW, 1.46 in AAM, 1.41 in WW, and 1.68 in WM. The HRRs decreased 4.6% in AAW, 1.4% in WW, 5.7% in AAM, and 3.0% in WM, but increased 2.1% in AAM after adjustment for selected covariates. FRS predicts incident CHD in African Americans and Whites, men and women. The relation of FRS to incident CHD can be only partially explained by the selected risk factors in the biological causal pathways: IMT, T-G, LDL, HDL, Lp(a), fibrinogen and hypertension. No significant difference by race has been found in this study.

Plasma homocysteine distribution and its association with parental history of coronary artery disease in black and white children: the Bogalusa Heart Study

BACKGROUND

Elevated homocysteine is associated with increased risk for coronary artery disease (CAD) in adults, but its distribution in children is not well documented. We examined the distribution of homocysteine in children and its relation to parental history of CAD.

METHODS AND RESULTS

A subsample of 1137 children (53% white, 47% black) aged 5 to 17 years in 1992 to 1994 examined in the Bogalusa Heart Study (n=3135), including all with a positive parental history of CAD (n=154), had plasma homocysteine levels measured. Homocysteine correlated positively with age (r=0.16, P=0.001). No race or sex differences in homocysteine levels were observed; geometric mean (GM) levels were 5.8 micromol/L (95% CI, 5.6 to 6.1) among white males, 5.8 micromol/L (95% CI, 5.5 to 6.0) among white females, 5.6 micromol/L (95% CI, 5.4 to 5.8) among black males, and 5.6 micromol/L (95% CI, 5.4 to 5.9) among black females. Children with a positive parental history of CAD had a significantly greater age-adjusted GM homocysteine level (GM, 6.7 micromol/L; 95% CI, 6.4 to 7.1) than those without a positive history (GM, 5.6 micromol/L; 95% CI, 5.4 to 5.7); this relation was observed in each race-sex group.

CONCLUSIONS

Higher homocysteine levels were observed among children with a positive family history of CAD. Additional studies should elucidate the contribution of genetic, dietary, and other factors to homocysteine levels in children.

Risk factors in the offspring of women with premature coronary heart disease

Some studies suggest that first-degree relatives of female patients with premature coronary heart disease (CHD) are at greater risk for early disease than if the proband is a male patient. To examine coronary risk factors, related knowledge, attitudes, and beliefs concerning CHD risk, we screened a sample of 87 apparently healthy offspring (56 female subjects and 31 male subjects) of women with documented premature CHD. More than half of the offspring had total and low-density lipoprotein cholesterol levels above the recommended levels for primary prevention, 31% were current smokers, and 56% exercised fewer than three times a week. A high proportion were overweight with a high prevalence of central obesity. A total of 13% had only one major risk factor, a family history of premature CHD, 10% had two risk factors, 23% had three, and 54% had four or more CHD risk factors. When compared with the Framingham cohort, 29% of sons and 30% of daughters exceeded their age- and sex-specific average risk for having CHD in 10 years. Only 28% identified heredity as a major cause of CHD, and 47% perceived their risk for future myocardial infarction as less than or equal to that of others their age. These findings suggest that adult children of women with premature CHD have a high prevalence of modifiable risk factors and do not perceive themselves to be at risk for CHD.

Family history as a risk factor for primary cardiac arrest

BACKGROUND

The hypothesis that a family history of myocardial infarction (MI) or primary cardiac arrest (PCA) is an independent risk factor for primary cardiac arrest was examined in a population-based case-control study. In addition, we investigated whether recognized risk factors account for the familial aggregation of these cardiovascular events.

METHODS AND RESULTS

PCA cases, 25 to 74 years old, attended by paramedics during the period 1988 to 1994 and population-based control subjects matched for age and sex were identified from the community by random digit dialing. All subjects were free of recognized clinical heart disease and major comorbidity. A detailed history of MI and PCA in first-degree relatives was collected in interviews with the spouses of case and control subjects by trained interviewers using a standardized questionnaire. For each familial relationship, there was a higher rate of MI or primary cardiac arrest (MI/PCA) in relatives of case compared with relatives of control subjects. Overall, the rate of MI/PCA among first-degree relatives of cardiac arrest patients was almost 50% higher than that in first-degree relatives of control subjects (rate ratio [RR]=1.46; 95% CI=1.23 to 1.72). In a multivariate logistic model, family history of MI/PCA was associated with PCA (RR=1.57; 95% CI=1.27 to 1.95) even after adjustment for other common risk factors.

CONCLUSIONS

Family history of MI or PCA is positively associated with the risk of primary cardiac arrest. This association is mostly independent of familial aggregation of other common risk factors.

The Family Atherosclerosis Risk Intervention Study (FARIS): risk factor profiles of patients and their relatives following an acute cardiac event

BACKGROUND

Relatives of patients with coronary heart disease have a heightened risk of cardiovascular disease. Attendance at a family-based screening clinic after an acute cardiac event could motivate patients and relatives to modify their lifestyles.

AIMS

The Family Atherosclerosis Risk Intervention Study (FARIS) aimed to determine (i) whether a high proportion of patients and relatives would attend a special screening and prevention programme; (ii) whether the risk factor profiles of relatives would be worse than those in the general community; and (iii) whether ongoing management of patients and families together in a special clinic would improve risk factor profiles.

METHODS

Consecutive patients, together with spouse, siblings and offspring, aged 18 to 69 years, were randomly allocated three months after an acute cardiac event to attend a special outpatient clinic, a screening and advice group, or a control group. Risk factor measures were total cholesterol, HDL cholesterol (HDLC), systolic blood pressure (SBP), body mass index (BMI) and smoking behaviour. This paper presents the risk factor profiles of all FARIS attenders and compares those of family members, age adjusted, with risk factors measured in a multicentre urban cross-sectional survey conducted in the same period. Differences between groups were compared using t-tests for numerical variables and ANOVA and chi-square for categorical variables.

RESULTS

Six hundred and twenty-eight patients and 1723 family members were enrolled, representing 85.9% and 82.7% of eligible patients and relatives respectively. Risk factors were significantly worse amongst family members than among those in the population survey.

The relationship of conjoint traits of dyslipidemias between young offspring and their parents in a community-based sample

BACKGROUND

The relationship of dyslipidemias between young offspring and their parents was examined to evaluate its usefulness in predicting lipid disorders among parents and children.

METHODS

Young offspring ages 5-17 years and their parents were studied in a community-based sample of 477 families. The dyslipidemias were defined as: (1) isolated high low-density lipoprotein cholesterol (LDL-C); (2) isolated high triglycerides (TG) and/or low high-density lipoprotein cholesterol (HDL-C); and (3) combined, involving both above.

RESULTS

Children of parents with a given dyslipidemia type had the highest frequency of the same disorder (P < 0.001 to P < 0.05). In discriminant analyses only the corresponding disorders in their parents were selected into the models as significant predictors after controlling parental obesity. In terms of sensitivity, 54.8, 50.0, 66.7, and 69.1% of offspring could be correctly predicted for isolated TG/HDL-C, isolated LDL-C, combined, and any type of disorder, respectively, by the corresponding disorders in both parents. Likewise, the predictability of parent's dyslipidemia from their children's disorder was also modest.

CONCLUSION

The conjoint dyslipidemias have familial basis to provide rationale for parents or children to determine their own risk status; however, sensitivity and positive predictive values are not high enough to be useful as a selective screening tool.

Serum bilirubin distribution and its relation to cardiovascular risk in children and young adults

There is evidence that bilirubin functions as an endogenous tissue protector by its antioxidant and anti-complement actions, properties that are relevant to atherogenesis. Serum bilirubin distribution and its relation to cardiovascular risk were examined in 4156 individuals aged 5-30 years from a biracial (black white) community. Bilirubin levels showed significant differences related to race (whites > blacks) and sex (males > females, except in 5-10 year olds). In males the levels increased with age up to 24 years, while in females the changes were less conspicuous. Both adiposity and cigarette smoking associated independently and inversely with bilirubin. In addition, serum bilirubin correlated positively with HDL cholesterol and inversely with triglycerides, VLDL cholesterol, LDL cholesterol, insulin, glucose and systolic blood pressure although these correlations were significant only in certain age-race-sex groups. Offspring with a parental history of heart attack or hypertension had consistently lower bilirubin levels than those without such parental history. Thus, bilirubin may be an inverse risk factor for cardiovascular disease.

Verification of parental history of coronary artery disease and associations with adult offspring risk factors in a community sample: the Bogalusa Heart Study

Positive parental history of coronary artery disease (CAD) (myocardial infarction, angina, angioplasty, bypass surgery) reported by 371 of 1,930 black and white adults aged 18 to 31 years in 1988 to 1991 in the Bogalusa Heart Study was verified by interviewing parents or next-of-kin. Error rates in reporting information concerning parental CAD and risk factors in offspring with a positive and negative parental history of CAD were examined. The 371 subjects who reported a positive parental history represented 304 families. Parental CAD could not be verified in 43 (14.1%) instances, and false-positive reports occurred in 45 (14.8%) cases. Among 216 families with confirmed CAD histories, the father had CAD in 175 (81.0%) cases and the mother in 70 (32.4%) cases. Both parents had CAD in 29 (13.4%) families. Of the parents with CAD, 46% of the fathers and 25% of the mothers died. The mean age at clinical onset of CAD was 51 years. Offspring with a confirmed positive parental history (n = 271) had significantly higher (P < 0.05) adjusted serum total and low-density lipoprotein cholesterol, plasma insulin and glucose, body mass index, and triceps and subscapular skinfolds than subjects with a negative parental history (n = 1,253). Those with an unconfirmed positive parental history (n = 51) had higher mean plasma insulin and serum high-density lipoprotein levels than those with a negative parental history; low-density lipoprotein levels were similar. Family history of CAD remains a useful indicator for screening adults at risk of developing CAD. An unverified family history may underestimate the importance of particular risk factors in epidemiologic studies.

Lack of association of angiotensin I-converting enzyme gene polymorphism and premature myocardial infarction in Mauritian Indians

Eighty-five young Mauritian Indians, male survivors of premature myocardial infarction (MI) and thus belonging to a high risk group, were compared with 108 stringently selected controls for a possible association between premature MI and an insertion/deletion (I/D) polymorphism in the gene encoding angiotensin I-converting enzyme (ACE). The frequency of the D allele was 0.42 in the MI group and 0.43 in the control group, and thus no association between I/D polymorphism of ACE with susceptibility to early-onset MI was found in this population group. Other gene components of the renin-angiotensin system and lipid metabolism need to be explored to understand the genetic factors involved in causing MI at an early age.

Parental history of premature coronary heart disease: an independent risk factor of myocardial infarction

We assessed the role of parental history of premature coronary heart disease (CHD) in the risk of acute myocardial infarction (AMI) and the extent to which the risk associated with positive parental history was independent of other risk factors: smoking, high serum cholesterol, elevated blood pressure, diabetes and obesity, and of socioeconomic status. The study is a prospective 12-year follow-up of 15,620 men and women aged from 30 to 59 years in eastern Finland. Parental history of premature CHD was defined as either fatal or nonfatal myocardial infarction or angina pectoris before the age of 60 years. The end point of the follow-up was either nonfatal AMI or coronary death. The risk ratio (RR) of AMI associated with positive family history of either parent was 1.61 in men and 1.85 in women. The risk decreased only slightly when an adjustment was made for other risk factors, and did not change at all when an adjustment was made for the indicators of socioeconomic status. The risk was slightly higher for early AMI (< 55 years) compared with later AMI (> or = 55 years), RR 1.71 versus 1.50, among men and markedly higher, RR 2.87 versus 1.49, among women. These results from this population with an exceptionally high risk of CHD support the hypothesis that positive family history is an independent risk factor of AMI.

Mengele Medicus: Medicine's Nazi Heritage

Nazi medicine is commonly considered to be an aberration that began and ended with the horrors of the Hitler regime. But its beginnings were more gradual and its legacy more pernicious. Data derived from research conducted on unknowing and unwitting subjects in death camps continue to be cited in authoritative contemporary medical literature. Nazi medicine has become a part of the professional genotype of modern medicine. This continuing influence of Nazi medicine raises profound questions for the epistemology and morality of medicine.

Public health, cardiovascular disease and molecular biology

Rapid developments in molecular biology provide the tools to search for genetic markers of coronary heart disease. Already the angiotensin converting enzyme and the angiotensinogen genes have been implicated in myocardial infarction and hypertension. However, common conditions such as coronary disease raise special problems for genetics both in selection of suitable subjects and the use of informative genetic methods. Traditionally genetics has focused on the family; now it must broaden that view to identify markers that are relevant to the general community. The magnitude and complexity of the problem demands collaboration between epidemiologists, physicians, geneticists and laboratory scientists. This paper proposes a two stage approach to the genetics of coronary heart disease, beginning with affected relative pair linkage studies using the new generation gene maps to define chromosomal regions of interest. The thorough and systematic search using gene maps also offers the possibility of defining genetic markers of "hidden" coronary risk factors. In the second stage, candidate genes within these regions are examined in case-control association studies to identify simple markers that divide the population into groups with contrasting risk of coronary disease. It is important that families and cases are representative of the general population, otherwise the predictive value of the new genetic markers will be in doubt. In particular, genetic analyses should avoid the potential bias resulting from the exclusion of cases of sudden and unexpected coronary death.

The importance of family history in cerebrovascular disease

BACKGROUND AND PURPOSE

The role of genetics in cerebrovascular disease remains controversial. The purpose of this study was to assess the influence of family history on atherothrombotic infarction or transient ischemic attack.

METHODS

Ninety patients with stroke or transient ischemic attack and 90 age- and sex-matched community control subjects were studied prospectively. Medical and family histories were obtained from all subjects, and a complete physical examination was performed.

RESULTS

Eighty-five patients and 86 control subjects knew their family history for ischemic heart disease and stroke. A positive history for ischemic heart disease was present in 62 (73%) of the patients and 46 (53%) of the control subjects (P = .019), and a positive family history for stroke was present in 38 (47%) of the patients and 21 (24%) of the control subjects (P = .014).

CONCLUSIONS

Although a positive vascular family history was not an independent risk factor in a multivariate analysis, it was an excellent marker of the presence of other established vascular risk factors. Personal histories of ischemic heart disease, hypertension, and hyperlipidemia were found to be significant independent risk factors for stroke.

Genetic susceptibility to death from coronary heart disease in a study of twins

BACKGROUND

A family history of premature coronary heart disease has long been thought to be a risk factor for coronary heart disease. Using data from 26 years of follow-up of 21,004 Swedish twins born between 1886 and 1925, we investigated this issue further by assessing the risk of death from coronary heart disease in pairs of monozygotic and dizygotic twins.

METHODS

The study population consisted of 3298 monozygotic and 5964 dizygotic male twins and 4012 monozygotic and 7730 dizygotic female twins. The age at which one twin died of coronary heart disease was used as the primary independent variable to predict the risk of death from coronary heart disease in the other twin. Information about other risk factors was obtained from questionnaires administered in 1961 and 1963. Actuarial life-table analysis was used to estimate the cumulative probability of death from coronary heart disease. Relative-hazard estimates were obtained from a multivariate survival analysis.

RESULTS

Among the men, the relative hazard of death from coronary heart disease when one's twin died of coronary heart disease before the age of 55 years, as compared with the hazard when one's twin did not die before 55, was 8.1 (95 percent confidence interval, 2.7 to 24.5) for monozygotic twins and 3.8 (1.4 to 10.5) for dizygotic twins. Among the women, when one's twin died of coronary heart disease before the age of 65 years, the relative hazard was 15.0 (95 percent confidence interval, 7.1 to 31.9) for monozygotic twins and 2.6 (1.0 to 7.1) for dizygotic twins. Among both the men and the women, whether monozygotic or dizygotic twins, the magnitude of the relative hazard decreased as the age at which one's twin died of coronary heart disease increased. The ratio of the relative-hazard estimate for the monozygotic twins to the estimate for the dizygotic twins approached 1 with increasing age. These relative hazards were little influenced by other risk factors for coronary heart disease.

CONCLUSIONS

Our findings suggest that at younger ages, death from coronary heart disease is influenced by genetic factors in both women and men. The results also imply that the genetic effect decreases at older ages.

The next generation: poor compliance with risk factor guidelines in the children of parents with premature coronary heart disease

OBJECTIVES

The offspring of individuals with premature coronary heart disease are themselves at increased risk for myocardial infarction before the age of 55. Consensus panels have recommended that all such offspring undergo an evaluation of cardiovascular risk, including cholesterol testing.

METHODS

To examine self-reported rates of cardiovascular risk factor assessment in this population, we conducted a telephone survey of 318 Canadian adults with premature coronary heart disease and of one offspring from 298 (94%) of the 318 families.

RESULTS

The median age of the offspring was 20 years (range 2 to 39 y). Among the 219 late adolescent and young adult offspring, only 97 (44%) reported having had a blood cholesterol measurement during the preceding 3 years. Thirty-seven percent reported being current smokers, 31% were overweight, and 30% exercised fewer than three times per week. Men were less likely than women to report having had their blood pressure measured in the preceding year (57% vs 80%).

CONCLUSION

These low rates of cardiac risk factor assessment families of patients with premature coronary heart disease represent missed opportunities for primary prevention. More effective strategies to prevent atherosclerosis in this population are needed.