New susceptibility alleles associated with severe coronary artery stenosis in the Lebanese population.

BACKGROUND: Coronary Artery Disease (CAD) is the narrowing or blockage of the coronary arteries. It is closely associated with numerous genetics and environmental factors that have been extensively evaluated in various populations. In recent studies, severe phenotypes have been strongly linked to genetic risk factors. METHODS: This study investigated the association of clinical, demographic, and genetic factors with severe coronary artery stenosis phenotypes in our population composed of 1734 individuals with severe coronary stenosis (≥ 50% in coronary vessels) and comparing them to 757 controls with no evidence of stenosis on angiography. We performed generalized linear model (GLM) genome-wide association studies to evaluate three stratification models and their associations to characteristics of the clinical disease. In model 1, patients were not stratified. In model 2, patients were stratified based on presence or absence of CAD family history (FxCAD). In model 3, patients were stratified by young age of CAD onset. RESULTS: Eight SNPs (single nucleotide polymorphism) were significantly associated with severe CAD phenotypes in the various models [Formula: see text], four of these SNPs were associated with severe CAD and the four others were specifically significant for young CAD patients. While these SNPs were not previously reported for association with CAD, six of them are present in genes that have already been linked to coronary disease. CONCLUSION: In conclusion, this study presents new genetic factors associated with severe stenosis and highlights different risk factors associated with a young age at diagnosis of CAD.

Correction: Genome-wide association analysis of HDL-C in a Lebanese cohort.

[This corrects the article DOI: 10.1371/journal.pone.0218443.].

Genome-wide association analysis of HDL-C in a Lebanese cohort.

Low serum levels of high-density lipoprotein cholesterol (HDL-C) have been shown to be a risk factor for coronary artery disease independent of low-density lipoprotein cholesterol (LDL-C) in different populations. In this study, we investigated genetic variants through genome-wide association studies to determine their association with HDL-C levels in a sample of 2,700 patients. We identified several SNPs associated with HDL-C levels in the Lebanese population using unadjusted and adjusted by biological factors models. We replicated the association of rs3764261 within CETP with HDL-C levels in the study population, and found other previously unidentified SNPs to be significant at the suggestive level, in both previously identified and unidentified genes. This paper reports the first genome-wide analysis of HDL-C in the Lebanese, Middle Eastern, population and supports the importance of genome-wide association studies across different and minor ethnicities to understand better the etiology of complex human diseases.

Gestational diabetes mellitus and macrosomia predispose to diabetes in the Lebanese population.

AIMS: The Middle East has the fastest rising rate of Type 2 Diabetes Mellitus (T2DM) worldwide, with Lebanon having 15.8% of its population affected. This study aims at studying Polycystic Ovarian Syndrome (PCOS), Gestational Diabetes Mellitus (GDM), and macrosomia as risk factors of T2DM in Lebanon. Such epidemiological and statistical study has never been conducted before in the Middle East region and would be useful for clinical diagnosis. METHODS: Our cohort is comprised of 1453 Lebanese individuals, with 897 controls and 556 patients. We tested the correlation between T2DM and the covariates GDM, PCOS, and macrosomia independently. We conducted multinomial logistic regression and cross tabulations with T2DM as an outcome. RESULTS: The results showed a significant association of the independent factors GDM and macrosomia with T2DM. The risk of having T2DM was increased by 4.192 times with the GDM, and by 2.315 times with macrosomia respectively. CONCLUSION: In conclusion, GDM and macrosomia, but not PCOS, are significant risk factors for T2DM in our Lebanese cohort. Our results, reported for the first time in the Middle East, present insights into risk factors management and disease prevention.

Caffeine Impact on Metabolic Syndrome Components Is Modulated by a CYP1A2 Variant.

Cultural, dietary, and lifestyle factors are the main modulators of type 2 diabetes mellitus (T2DM) disease risk. Coffee is one of the most popular worldwide beverages, and recent epidemiological studies have showed that coffee consumption is associated with a lower risk of T2DM. This study investigates the impact of coffee intake on T2DM risk and assesses the effect of CYP variants with caffeine exposures on T2DM. Data from 7,607 study subjects were analyzed by logistic regression models, among whom 3,290 GWAS data were available for CYP variants association studies using Plink analysis. These data suggest a protective relationship for women, but not for men; however, the results were not statistically significant in this dataset and there is a significant interaction in favor of women regarding heavy coffee consumption. The interaction between male gender and heavy coffee consumption becomes significant, thereby tending to cancel the protective effect of coffee for males. CYP rs2470890 allele 'C' increases the odds of T2DM by a factor of around 1.2 but decreases the odds of caffeine boosting T2DM of 1.7 by a factor of 0.77. rs2470890 showed an association with T2DM only when the interaction with coffee was considered, thereby setting an example of genetic activation by dietary changes associating with metabolic syndrome.

Association of coronary artery disease and chronic kidney disease in Lebanese population.

BACKGROUND: More evidence is emerging on the strong association between chronic kidney disease (CKD) and cardiovascular disease. We assessed the relationship between coronary artery disease (CAD) and renal dysfunction level (RDL) in a group of Lebanese patients. METHODS: A total of 1268 patients undergoing cardiac catheterization were sequentially enrolled in a multicenter cross sectional study. Angiograms were reviewed and CAD severity scores (CADSS) were determined. Estimated glomerular filtration rate (eGFR) was calculated and clinical and laboratory data were obtained. CKD was defined as eGFR < 60 ml/min. Logistic regression model was performed using multivariate analysis including all traditional risk factors associated with both diseases. ANOVA and the Tukeytestswere used to compare subgroups of patients and to assess the impact of each disease on the severity of the other. RESULTS: Among the 82% patients who exhibited variable degrees of CAD, 20.6% had an eGFR < 60 ml/min. Logistic regression analysis revealed a bidirectional independent association between CAD and CKD with an OR = 2.01 (P < 0.01) and an OR = 1.99 (P < 0.01) for CAD and CKD frequencies, respectively. We observed a steady increase in the CADSS mean as eGFR declined and a progressive reduction in renal function with the worsening of CAD (P < 0.05). This correlation remained highly significant despite considerable inter-patient variability and was at its highest at the most advanced stages of both diseases. CONCLUSIONS: Our results show a strong, independent and graded bidirectional relationship between CAD severity and RDL. We propose to add CAD to the list of risk factors for the development and progression of CKD.

Circulating lipid levels and risk of coronary artery disease in a large group of patients undergoing coronary angiography.

A main underlying pathology of coronary artery disease is the deposition of cholesterol in the arteries supplying blood to the heart that leads to stenosis and myocardial infarction. We tested if dyslipidemia is a risk factor for coronary artery disease in the Lebanese population, and studied the role of the total cholesterol/HDL cholesterol (TC/HDL-C) ratio as a biological marker of coronary artery disease. We recruited 6,180 Lebanese patients undergoing cardiac catheterization. We conducted a cross-sectional association study between TC/HDL-C ratio and the number and type of vessels occluded in catheterized patients by controlling for confounding effects. The TC/HDL-C ratio ≥4 significantly predicts ≥50 % stenosis in all vessels individually with the odds ratio (OR) ranging from 1.22 to 1.92. The OR increased with increasing number of ≥50 % stenotic vessels (1.39 for 2 vessels and 1.64 for 3-4 vessels), as did risk due to diabetes, CAD family history, gender, and age. The younger than average age of onset subgroup shows a pronounced increase in risk for occlusion of the left main coronary artery due to TC/HDL-C ≥4 (OR 3.26). In conclusion, low levels of HDL-cholesterol and high levels TC/HDL-C ratio are strong biological markers of disease occurrence and severity in the Lebanese population.

T2DM GWAS in the Lebanese population confirms the role of TCF7L2 and CDKAL1 in disease susceptibility.

Genome-wide association studies (GWAS) of multiple populations with distinctive genetic and lifestyle backgrounds are crucial to the understanding of Type 2 Diabetes Mellitus (T2DM) pathophysiology. We report a GWAS on the genetic basis of T2DM in a 3,286 Lebanese participants. More than 5,000,000 SNPs were directly genotyped or imputed using the 1000 Genomes Project reference panels. We identify genome-wide significant variants in two loci CDKAL1 and TCF7L2, independent of sex, age and BMI, with leading variants rs7766070 (OR = 1.39, P = 4.77 × 10(-9)) and rs34872471 (OR = 1.35, P = 1.01 × 10(-8)) respectively. The current study is the first GWAS to find genomic regions implicated in T2DM in the Lebanese population. The results support a central role of CDKAL1 and TCF7L2 in T2DM susceptibility in Southwest Asian populations and provide a plausible component for understanding molecular mechanisms involved in the disease.

Association of hypertension with coronary artery disease onset in the Lebanese population.

The onset of coronary artery disease (CAD) is influenced by cardiovascular risk factors that often occur in clusters and may build on one another. The objective of this study is to examine the relationship between hypertension and CAD age of onset in the Lebanese population. This retrospective analysis was performed on data extracted from Lebanese patients (n = 3,753). Logistic regression examined the association of hypertension with the age at CAD diagnosis after controlling for other traditional risk factors. The effect of antihypertensive drugs and lifestyle changes on the onset of CAD was also investigated. Results showed that hypertension is associated with late onset CAD (OR=0.656, 95% CI=0.504-0.853, p=0.001). Use of antihypertensive drugs showed a similar association with delayed CAD onset. When comparing age of onset in CAD patients with traditional risk factors such as hypertension, diabetes, hyperlipidemia, obesity, smoking and family history of CAD, the age of onset was significantly higher for patients with hypertension compared to those with any of the other risk factors studied (p < 0.001). In conclusion, hypertension and its treatment are associated with late coronary atherosclerotic manifestations in Lebanese population. This observation is currently under investigation to clarify its genetic and/or environmental mechanisms.

Multivariate epidemiologic analysis of type 2 diabetes mellitus risks in the Lebanese population.

BACKGROUND: The burden of diabetes in Lebanon requires well-targeted interventions for screening type 2 diabetes mellitus (T2DM) and prediabetes and prevention of risk factors. Newly recruited 998 Lebanese individuals, in addition to 7,292 already available, were studied to investigate the prevalence of diabetes, prediabetes and their associated risk factors. METHODS: Participants had fasting blood sugar and glycohemoglobin tests in addition to a lipid profile. Clinical and demographic information were obtained from a detailed questionnaire. The relationship between T2DM, its risk factors, and its complications were tested. Comparisons of these risk factors among diabetics, healthy, and coronary artery disease (CAD) patients were performed. RESULTS: The prevalence of T2DM significantly increased with increasing BMI (p < 0.0001). Exercise activity level negatively correlated with the disease (p = 0.002), whereas the prevalence of T2DM (p < 0.0001) and CAD family history (p = 0.006) positively correlated with the affection status. The mean levels of triglycerides and LDL-C were significantly higher in diabetics (1.87; 1.35) compared to individuals with prediabetes (1.63; 1.26) and unaffected controls (1.49; 1.19). People with T2DM showed a significant decrease in HDL-C levels. A strong correlation of overall hyperlipidemia with the diabetes affection status was shown (p < 0.0001). Other comorbid factors such as hypertension (p < 0.0001) and self-reported obesity (p < 0.0001) were highly associated with T2DM and prediabetes. Reproductive health of women showed a strong correlation between giving birth to a baby with a high weight and the occurrence of T2DM and prediabetes later in life (p < 0.0001). Retinopathy and peripheral neuropathy were significantly correlated with diabetes and prediabetes (p < 0.0001). CONCLUSIONS: The present study shows an alarming prevalence of diabetes and prediabetes in the studied subgroups representative of the Lebanese population.

Genome-wide association study in a Lebanese cohort confirms PHACTR1 as a major determinant of coronary artery stenosis.

The manifestation of coronary artery disease (CAD) follows a well-choreographed series of events that includes damage of arterial endothelial cells and deposition of lipids in the sub-endothelial layers. Genome-wide association studies (GWAS) of multiple populations with distinctive genetic and lifestyle backgrounds are a crucial step in understanding global CAD pathophysiology. In this study, we report a GWAS on the genetic basis of arterial stenosis as measured by cardiac catheterization in a Lebanese population. The locus of the phosphatase and actin regulator 1 gene (PHACTR1) showed association with coronary stenosis in a discovery experiment with genome wide data in 1,949 individuals (rs9349379, OR = 1.37, p = 1.57×10(-5)). The association was replicated in an additional 2,547 individuals (OR = 1.31, p = 8.85×10(-6)), leading to genome-wide significant association in a combined analysis (OR = 1.34, p = 8.02×10(-10)). Results from this GWAS support a central role of PHACTR1 in CAD susceptibility irrespective of lifestyle and ethnic divergences. This association provides a plausible component for understanding molecular mechanisms involved in the formation of stenosis in cardiac vessels and a potential drug target against CAD.

Genetic and environmental influences on total plasma homocysteine and its role in coronary artery disease risk.

BACKGROUND: Elevated levels of total plasma homocysteine are a risk factor for atherosclerotic disease. AIMS: The rationale behind this study is to explore the correlation between degree and site of coronary lesion and hyperhomocysteinemia in Lebanese CAD patients and assess environmental and genetic factors for elevated levels of total plasma homocysteine. METHODS: A total of 2644 patients were analyzed for traditional CAD risk factors. Logistic regression was performed to determine the association of hyperhomocysteinemia with degree and site of coronary lesions controlling for risk factors. Environmental and genetic factors for hyperhomocysteinemia were analyzed by logistic regression using a candidate gene approach. RESULTS: Traditional risk factors were correlated with stenosis. Hyperhomocysteinemia associated with increased risk of overall stenosis, and risk of mild and severe occlusion in major arteries. Hyperhomocysteinemia and hypertension were highly correlated suggesting that hyperhomocysteinemia acts as a hypertensive agent leading to CAD. Diuretics and genetic polymorphisms in MTHFR and SLCO1B1 were associated with hyperhomocysteinemia. CONCLUSIONS: Hyperhomocysteinemia is a medical indicator of specific vessel stenosis in the Lebanese population. Hypertension is a major link between hyperhomocysteinemia and CAD occurrence. Genetic polymorphisms and diuretics' intake explain partly elevated homocysteine levels. This study has important implications in CAD risk prediction.

Large scale association analysis identifies three susceptibility loci for coronary artery disease.

Genome wide association studies (GWAS) and their replications that have associated DNA variants with myocardial infarction (MI) and/or coronary artery disease (CAD) are predominantly based on populations of European or Eastern Asian descent. Replication of the most significantly associated polymorphisms in multiple populations with distinctive genetic backgrounds and lifestyles is crucial to the understanding of the pathophysiology of a multifactorial disease like CAD. We have used our Lebanese cohort to perform a replication study of nine previously identified CAD/MI susceptibility loci (LTA, CDKN2A-CDKN2B, CELSR2-PSRC1-SORT1, CXCL12, MTHFD1L, WDR12, PCSK9, SH2B3, and SLC22A3), and 88 genes in related phenotypes. The study was conducted on 2,002 patients with detailed demographic, clinical characteristics, and cardiac catheterization results. One marker, rs6922269, in MTHFD1L was significantly protective against MI (OR=0.68, p=0.0035), while the variant rs4977574 in CDKN2A-CDKN2B was significantly associated with MI (OR=1.33, p=0.0086). Associations were detected after adjustment for family history of CAD, gender, hypertension, hyperlipidemia, diabetes, and smoking. The parallel study of 88 previously published genes in related phenotypes encompassed 20,225 markers, three quarters of which with imputed genotypes The study was based on our genome-wide genotype data set, with imputation across the whole genome to HapMap II release 22 using HapMap CEU population as a reference. Analysis was conducted on both the genotyped and imputed variants in the 88 regions covering selected genes. This approach replicated HNRNPA3P1-CXCL12 association with CAD and identified new significant associations of CDKAL1, ST6GAL1, and PTPRD with CAD. Our study provides evidence for the importance of the multifactorial aspect of CAD/MI and describes genes predisposing to their etiology.