Search

Genetic variation at chromosome 9p21 is a recognized risk factor for coronary heart disease (CHD). However, its effect on disease progression and subsequent events is unclear, raising questions about its value for stratification of residual risk.A variant at chromosome 9p21 (rs1333049) was tested for association with subsequent events during follow-up in 103 357 Europeans with established CHD at baseline from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) Consortium (73.1% male, mean age 62.9 years). The primary outcome, subsequent CHD death or myocardial infarction (CHD death/myocardial infarction), occurred in 13 040 of the 93 115 participants with available outcome data. Effect estimates were compared with case/control risk obtained from the CARDIoGRAMplusC4D consortium (Coronary Artery Disease Genome-wide Replication and Meta-analysis [CARDIoGRAM] plus The Coronary Artery Disease [C4D] Genetics) including 47 222 CHD cases and 122 264 controls free of CHD.Meta-analyses revealed no significant association between chromosome 9p21 and the primary outcome of CHD death/myocardial infarction among those with established CHD at baseline (GENIUS-CHD odds ratio, 1.02; 95% CI, 0.99-1.05). This contrasted with a strong association in CARDIoGRAMPlusC4D odds ratio 1.20; 95% CI, 1.18-1.22; P for interaction0.001 compared with the GENIUS-CHD estimate. Similarly, no clear associations were identified for additional subsequent outcomes, including all-cause death, although we found a modest positive association between chromosome 9p21 and subsequent revascularization (odds ratio, 1.07; 95% CI, 1.04-1.09).In contrast to studies comparing individuals with CHD to disease-free controls, we found no clear association between genetic variation at chromosome 9p21 and risk of subsequent acute CHD events when all individuals had CHD at baseline. However, the association with subsequent revascularization may support the postulated mechanism of chromosome 9p21 for promoting atheroma development.

Background: Flucloxacillin is an established cause of liver injury. Despite this, there are a lack of published data on both the strength of association after adjusting for potential confounders, and the absolute incidence among different subgroups of patients. Objectives: To assess the relative and absolute risks of liver injury following exposure to flucloxacillin and identify subgroups at potentially increased risk. Methods: A cohort study between 1 January 2000 and 1 January 2012 using the UK Clinical Practice Research Datalink, including 1046699 people with a first prescription for flucloxacillin (861962) or oxytetracycline (184737). Absolute risks of experiencing both symptom-defined (jaundice) and laboratory-confirmed liver injury within 1-45 and 46-90 days of antibiotic initiation were estimated. Multivariable logistic regression was used to estimate 1-45 day relative effects. Results: There were 183 symptom-defined cases (160 prescribed flucloxacillin) and 108 laboratory-confirmed cases (102 flucloxacillin). The 1-45 day adjusted risk ratio for laboratory-confirmed injury was 5.22 (95% CI 1.64-16.62) comparing flucloxacillin with oxytetracycline use. The 1-45 day risk of laboratoryconfirmed liver injury was 8.47 per 100000 people prescribed flucloxacillin (95% CI 6.64-10.65). People who received consecutive flucloxacillin prescriptions had a 1-45 day risk of jaundice of 39.00 per 100000 (95% CI 26.85-54.77), while those aged > 70 receiving consecutive prescriptions had a risk of 110.57 per 100000 (95% CI 70.86-164.48). Conclusions: The short-term risk of laboratory-confirmed liver injury was > 5-fold higher after a flucloxacillin prescription than an oxytetracycline prescription. The risk of flucloxacillin-induced liver injury is particularly high within those aged > 70 and those who receive multiple flucloxacillin prescriptions. The stratified risk estimates from this study could help guide clinical care.

Coronary artery disease (CAD) has a significant genetic contribution that is incompletely characterized. To complement genome-wide association (GWA) studies, we conducted a large and systematic candidate gene study of CAD susceptibility, including analysis of many uncommon and functional variants. We examined 49,094 genetic variants in ∼2,100 genes of cardiovascular relevance, using a customised gene array in 15,596 CAD cases and 34,992 controls (11,202 cases and 30,733 controls of European descent; 4,394 cases and 4,259 controls of South Asian origin). We attempted to replicate putative novel associations in an additional 17,121 CAD cases and 40,473 controls. Potential mechanisms through which the novel variants could affect CAD risk were explored through association tests with vascular risk factors and gene expression. We confirmed associations of several previously known CAD susceptibility loci (eg, 9p21.3:p, Author Summary Coronary artery disease (CAD) has a strong genetic basis that remains poorly characterised. Using a custom-designed array, we tested the association with CAD of almost 50,000 common and low frequency variants in ∼2,000 genes of known or suspected cardiovascular relevance. We genotyped the array in 15,596 CAD cases and 34,992 controls (11,202 cases and 30,733 controls of European descent; 4,394 cases and 4,259 controls of South Asian origin) and attempted to replicate putative novel associations in an additional 17,121 CAD cases and 40,473 controls. We report the novel association of variants in or near four genes with CAD and in additional studies identify potential mechanisms by which some of these novel variants affect CAD risk. Interestingly, we found that these variants, as well as the majority of previously reported CAD variants, have similar associations in Europeans and South Asians. Contrary to prior expectations, many previously suggested candidate genes did not show evidence of any effect on CAD risk, and neither did we identify any novel low frequency alleles with strong effects amongst the genes tested. Discovery of novel genes associated with heart disease may help to further understand the aetiology of cardiovascular disease and identify new targets for therapeutic interventions.

© 2015 Swerdlow et al. Open Access article distributed under the terms of CC BY. Background Statins increase the risk of new-onset type 2 diabetes mellitus. We aimed to assess whether this increase in risk is a consequence of inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the intended drug target. Methods We used single nucleotide polymorphisms in the HMGCR gene, rs17238484 (for the main analysis) and rs12916 (for a subsidiary analysis) as proxies for HMGCR inhibition by statins. We examined associations of these variants with plasma lipid, glucose, and insulin concentrations; bodyweight; waist circumference; and prevalent and incident type 2 diabetes. Study-specific effect estimates per copy of each LDL-lowering allele were pooled by meta-analysis. These findings were compared with a meta-analysis of new-onset type 2 diabetes and bodyweight change data from randomised trials of statin drugs. The effects of statins in each randomised trial were assessed using meta-analysis. Findings Data were available for up to 223 463 individuals from 43 genetic studies. Each additional rs17238484-G allele was associated with a mean 0·06 mmol/L (95% CI 0·05-0·07) lower LDL cholesterol and higher body weight (0·30 kg, 0·18-0·43), waist circumference (0·32 cm, 0·16-0·47), plasma insulin concentration (1·62%, 0·53-2·72), and plasma glucose concentration (0·23%, 0·02-0·44). The rs12916 SNP had similar effects on LDL cholesterol, bodyweight, and waist circumference. The rs17238484-G allele seemed to be associated with higher risk of type 2 diabetes (odds ratio [OR] per allele 1·02, 95% CI 1·00-1·05); the rs12916-T allele association was consistent (1·06, 1·03-1·09). In 129 170 individuals in randomised trials, statins lowered LDL cholesterol by 0·92 mmol/L (95% CI 0·18-1·67) at 1-year of follow-up, increased bodyweight by 0·24 kg (95% CI 0·10-0·38 in all trials; 0·33 kg, 95% CI 0·24-0·42 in placebo or standard care controlled trials and -0·15 kg, 95% CI -0·39 to 0·08 in intensive-dose vs moderate-dose trials) at a mean of 4·2 years (range 1·9-6·7) of follow-up, and increased the odds of new-onset type 2 diabetes (OR 1·12, 95% CI 1·06-1·18 in all trials; 1·11, 95% CI 1·03-1·20 in placebo or standard care controlled trials and 1·12, 95% CI 1·04-1·22 in intensive-dose vs moderate dose trials). Interpretation The increased risk of type 2 diabetes noted with statins is at least partially explained by HMGCR inhibition. Funding The funding sources are cited at the end of the paper.

Objective: To use the rs1229984 variant in the alcohol dehydrogenase 1B gene (ADH1B) as an instrument to investigate the causal role of alcohol in cardiovascular disease. Design: Mendelian randomisation meta-analysis of 56 epidemiological studies. Participants: 261 991 individuals of European descent, including 20 259 coronary heart disease cases and 10 164 stroke events. Data were available on ADH1B rs1229984 variant, alcohol phenotypes, and cardiovascular biomarkers. Main outcome measures: Odds ratio for coronary heart disease and stroke associated with the ADH1B variant in all individuals and by categories of alcohol consumption. Results: Carriers of the A-allele of ADH1B rs1229984 consumed 17.2% fewer units of alcohol per week (95% confidence interval 15.6% to 18.9%), had a lower prevalence of binge drinking (odds ratio 0.78 (95% CI 0.73 to 0.84)), and had higher abstention (odds ratio 1.27 (1.21 to 1.34)) than non-carriers. Rs1229984 A-allele carriers had lower systolic blood pressure (-0.88 (-1.19 to -0.56) mm Hg), interleukin-6 levels (-5.2% (-7.8 to -2.4%)), waist circumference (-0.3 (-0.6 to -0.1) cm), and body mass index (-0.17 (-0.24 to -0.10) kg/m2). Rs1229984 A-allele carriers had lower odds of coronary heart disease (odds ratio 0.90 (0.84 to 0.96)). The protective association of the ADH1B rs1229984 A-allele variant remained the same across all categories of alcohol consumption (P=0.83 for heterogeneity). Although no association of rs1229984 was identified with the combined subtypes of stroke, carriers of the A-allele had lower odds of ischaemic stroke (odds ratio 0.83 (0.72 to 0.95)). Conclusions: Individuals with a genetic variant associated with non-drinking and lower alcohol consumption had a more favourable cardiovascular profile and a reduced risk of coronary heart disease than those without the genetic variant. This suggests that reduction of alcohol consumption, even for light to moderate drinkers, is beneficial for cardiovascular health.

Robert Clarke and colleagues conduct a meta-analysis of unpublished datasets to examine the causal relationship between elevation of homocysteine levels in the blood and the risk of coronary heart disease. Their data suggest that an increase in homocysteine levels is not likely to result in an increase in risk of coronary heart disease., Background Moderately elevated blood levels of homocysteine are weakly correlated with coronary heart disease (CHD) risk, but causality remains uncertain. When folate levels are low, the TT genotype of the common C677T polymorphism (rs1801133) of the methylene tetrahydrofolate reductase gene (MTHFR) appreciably increases homocysteine levels, so “Mendelian randomization” studies using this variant as an instrumental variable could help test causality. Methods and Findings Nineteen unpublished datasets were obtained (total 48,175 CHD cases and 67,961 controls) in which multiple genetic variants had been measured, including MTHFR C677T. These datasets did not include measurements of blood homocysteine, but homocysteine levels would be expected to be about 20% higher with TT than with CC genotype in the populations studied. In meta-analyses of these unpublished datasets, the case-control CHD odds ratio (OR) and 95% CI comparing TT versus CC homozygotes was 1.02 (0.98–1.07; p = 0.28) overall, and 1.01 (0.95–1.07) in unsupplemented low-folate populations. By contrast, in a slightly updated meta-analysis of the 86 published studies (28,617 CHD cases and 41,857 controls), the OR was 1.15 (1.09–1.21), significantly discrepant (p = 0.001) with the OR in the unpublished datasets. Within the meta-analysis of published studies, the OR was 1.12 (1.04–1.21) in the 14 larger studies (those with variance of log OR, Editors' Summary Background Coronary heart disease (CHD) is the leading cause of death among adults in developed countries. With age, fatty deposits (atherosclerotic plaques) coat the walls of the coronary arteries, the blood vessels that supply the heart with oxygen and nutrients. The resultant restriction of the heart's blood supply causes shortness of breath, angina (chest pains that are usually relieved by rest), and sometimes fatal heart attacks. Many established risk factors for CHD, including smoking, physical inactivity, being overweight, and eating a fat-rich diet, can be modified by lifestyle changes. Another possible modifiable risk factor for CHD is a high blood level of the amino acid homocysteine. Methylene tetrahydofolate reductase, which is encoded by the MTHFR gene, uses folate to break down and remove homocysteine so fortification of cereals with folate can reduce population homocysteine blood levels. Pooled results from prospective observational studies that have looked for an association between homocysteine levels and later development of CHD suggest that the reduction in homocysteine levels that can be achieved by folate supplementation is associated with an 11% lower CHD risk. Why Was This Study Done? Prospective observational studies cannot prove that high homocysteine levels cause CHD because of confounding, the potential presence of other unknown shared characteristics that really cause CHD. However, an approach called “Mendelian randomization” can test whether high blood homocysteine causes CHD. A common genetic variant of the MTHFR gene—the C677T polymorphism—reduces MTHFR efficiency so TT homozygotes (individuals in whom both copies of the MTHFR gene have the nucleotide thymine at position 677; the human genome contains two copies of most genes) have 25% higher blood homocysteine levels than CC homozygotes. In meta-analyses (statistical pooling of the results of several studies) of published Mendelian randomized studies, TT homozygotes have a higher CHD risk than CC homozygotes. Because gene variants are inherited randomly, they are not subject to confounding, so this result suggests that high blood homocysteine causes CHD. But what if only Mendelian randomization studies that found an association have been published? Such publication bias would affect this aggregate result. Here, the researchers investigate the association of the MTHFR C677T polymorphism with CHD in unpublished datasets that have analyzed this polymorphism incidentally during other genetic studies. What Did the Researchers Do and Find? The researchers obtained 19 unpublished datasets that contained data on the MTHFR C677T polymorphism in thousands of people with and without CHD. Meta-analysis of these datasets indicates that the excess CHD risk in TT homozygotes compared to CC homozygotes was 2% (much lower than predicted from the prospective observational studies), a nonsignificant difference (that is, it could have occurred by chance). When the probable folate status of the study populations (based on when national folic acid fortification legislation came into effect) was taken into account, there was still no evidence that TT homozygotes had an excess CHD risk. By contrast, in an updated meta-analysis of 86 published studies of the association of the polymorphism with CHD, the excess CHD risk in TT homozygotes compared to CC homozygotes was 15%. Finally, in a meta-analysis of randomized trials on the use of vitamin B supplements for homocysteine reduction, folate supplementation had no significant effect on the 5-year incidence of CHD. What Do These Findings Mean? These analyses of unpublished datasets are consistent with lifelong moderate elevation of homocysteine levels having no significant effect on CHD risk. In other words, these findings indicate that circulating homocysteine levels within the normal range are not causally related to CHD risk. The meta-analysis of the randomized trials of folate supplementation also supports this conclusion. So why is there a discrepancy between these findings and those of meta-analyses of published Mendelian randomization studies? The discrepancy is too large to be dismissed as a chance finding, suggest the researchers, but could be the result of publication bias—some studies might have been prioritized for publication because of the positive nature of their results whereas the unpublished datasets used in this study would not have been affected by any failure to publish null results. Overall, these findings reveal a serious example of publication bias and argue against the use of folate supplements as a means of reducing CHD risk. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001177. The American Heart Association provides information about CHD and tips on keeping the heart healthy; it also provides information on homocysteine, folic acid, and CHD, general information on supplements and heart health, and personal stories about CHD The UK National Health Service Choices website provides information about CHD, including personal stories about CHD Information is available from the British Heart Foundation on heart disease and keeping the heart healthy The US National Heart Lung and Blood Institute also provides information on CHD (in English and Spanish) MedlinePlus provides links to many other sources of information on CHD (in English and Spanish) Wikipedia has a page on Mendelian randomization (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)

Purpose In epidemiological studies, non-response may introduce bias and limit generalizability. In genetic pharmacoepidemiological research, collection of DNA might be a major reason for non-response. We determined reasons for non-response and compared characteristics of non-responders and responders in a pharmacogenetic case-control study. Methods Myocardial infarction (MI) cases and controls, who were antihypertensive drug users, were recruited through community pharmacies that participate in the Pharmaco-Morbidity-Record-Linkage-System (PHARMO). The PHARMO database comprises drug dispensing histories of about 2 000 000 subjects from a representative sample of Dutch community pharmacies linked to the national registry of hospital discharges. Independent samples t-test and ANOVA-statistics were used to analyse the differences in continuous variables between responders and non-responders. chi(2) statistics and logistic regression were used to compare categorical variables. Results We approached 1871 cases and 14 102 controls of whom 794 MI cases (42.4%) and 4997 controls (35.4%) responded. We could not approach 2194 patients of whom 63.1% had died and 31.2% moved to another pharmacy. Main reasons for non-response were health problems or hospital stays (16.2%, OR 1.47; 95%CI: 1.00-2.16). Other reasons were old age or dementia (16.9%, OR 1.82; 95%CI: 1.24-2.65). Only a small percentage (1.1%, OR 1.43; 95%CI: 0.41-5.03) mentioned DNA sampling as a reason. About 30% of the non-responders did not give a reason. Women were statistically significantly (p < 0.0005) less willing to participate than men (38.8% versus 31.3%). An association with age was also found (mean age 64.6 versus 66.5 yrs) (p < 0.0005). Conclusion In a pharmacogenetic case-control study fear for genetic screening was not a major reported reason for non-response. Females were less willing to participate than males. Copyright (C) 2009 John Wiley & Sons, Ltd.

Objective: Adherence to antihypertensive drug treatment is suboptimal. The present study investigates the effect of early treatment discontinuation with anti hypertensive drugs on the risk of acute myocardial infarction (AMI) or stroke in daily clinical practice. Methods: In the PHARMO Record Linkage System, which includes all records of drug dispensings and hospitalisations for >= 2 million subjects in the Netherlands, new users of antihypertensive (AHT) drugs >= 18 years of age were studied during the period 1 January 1993 - 1 October 2002 to determine the risk of AMI or stroke related to persistence with AHT Patients were initially followed for 2 years to determine persistence with AHT, and then for a further 2 years or until the first hospital admission for AMI or stroke, death, or end of the study period. Patients using AHT for secondary prevention of cardiovascular disease were excluded from the study cohort. Results: The study cohort included 77193 AHT users. The percentage of non-persistent patients was 55% at 2 years, with the lowest non-persistence rates for angiotensin-receptor blockers (ARBs) and ACE-inhibitors (40%) and the highest rates for beta-blockers, calcium-channel blockers (CCBs) and diuretics (54-61%). Non-persistent AHT use was associated with a 15% increased risk of AMI (RR 1.15; 95% CI 1.00-1.33) and a 28% increased risk of stroke (RR 1.28; 95% CI 1.15-1.45). Conclusions: The results of this study show that in daily clinical practice early discontinuation of antihypertensive drug treatment in primary prevention increases the risk of subsequent AMI or stroke.

(B)ackground: Several studies have indicated that type 2 diabetes mellitus is more common among schizophrenic patients than in the general population. In this study, we investigated whether the use of antipsychotic drugs in patients with diabetes leads to worsening of glycemic control. Method: In this cohort study, patients with newly diagnosed type 2 diabetes were selected from the PHARMO Record Linkage System, which comprises pharmacy records for all 320,000 residents of 6 Dutch cities. In total, we identified 2585 patients with incident cases of type 2 diabetes who began treatment with oral hypoglycemic agents between 1991 and 1997 and had a medication history of at least 2 years after diagnosis of diabetes. A change in treatment from oral hypoglycemic agents alone to insulin therapy (with or without continuation of oral hypoglycemic agents) was considered a proxy for deterioration of beta-cell function. We compared the incidence of initiation of insulin therapy between users and nonusers of antipsychotic drugs by performing a Cox proportional hazards model analysis. Results: We found an increased risk for initiation of insulin therapy at 2 years after diagnosis of diabetes in users of antipsychotics compared with nonusers; the relative hazard (hazard ratio) was 2.0 (95% CI = 1.2 to 3.3), which did not change after adjustment for potential confounders. The risk decreased in the years after diagnosis of diabetes. Conclusion: It seems that use of antipsychotics by patients with type 2 diabetes mellitus is associated with initiation of insulin therapy (i.e., "secondary failure"), especially in the first 2 years of the disease.

Purpose The objective of this study was to determine the association between different antihypertensive drug therapies and lower extremity amputations (LEAs) in type 2 diabetes patients. Methods Data were obtained from the PHARMO Record Linkage System comprising pharmacy records and data on hospitalisations for all 450 000 residents of eight Dutch cities. In a nested case-control study among 12 140 type 2 diabetes patients who used antihypertensive drugs, 26 cases with a first LEA and 94 controls without a LEA matched on age, sex and calendar time were identified. Logistic regression was used to estimate the relative risk of LEA and to adjust for potential confounding factors. Results Among type 2 diabetes patients who used antihypertensive drugs, subjects who used thiazide diuretics, alone or in combination, had a higher risk of LEA compared to subjects who used Angiotensin Converting Enzyme (ACE) inhibitor monotherapy (crude odds ratio (OR): 6.11 [95% confidence interval (CI): 1.32-28.27]). The use of thiazide diuretics was also associated with an increased risk of LEA when compared to the use of any non-thiazide antihypertensive drug (adjusted OR: 7.04 [1.10-45.30]). The increased risk of LEA associated with the use of thiazides compared to the use of non-thiazides depended on the duration of use (adjusted ORless than or equal to365 days, 4.82 [0.61-38.34] and adjusted OR>365 days, 26.16 [1.02-674.02], p-trend = 0.01). Conclusions Treatment with thiazide diuretics compared to treatment with other antihypertensive drugs was associated with excess amputations in type 2 diabetes patients. Due to several limitations of this study, our findings do not preclude the use of thiazides in type 2 diabetes mellitus patients as yet. Copyright (C) 2004 John Wiley Sons, Ltd.

OBJECTIVE - To investigate cardiovascular drug use and hospitalizations attributable to type 2 diabetes from I year before until 6 years after the start of oral antidiabetic therapy. RESEARCH DESIGN AND METHODS - In this cohort study, 2,584 patients With type 2 diabetes were selected from the PHARMO Record Linkage System, comprising pharmacy records and hospitalizations for all 320,000 residents of six Dutch Cities. Patients with type 2 diabetes were identified as incident oral antidiabetic drug users between 1992 and 1997, Nondiabetic subjects were 1:1-matched for age, sex, pharmacy, and index date and received no insulin, oral antidiabetic drugs, or glucose-testing supplies, RESULTS - Patients with type 2 diabetes were more likely to use cardiovascular drugs (RR 1.28 [95% CI 1.23-1.34]) and to be hospitalized because of cardiovascular diseases (1.54 [1.33-1.78]) after the start of oral antidiabetic therapy than nondiabetic subjects, Differences between patients with type 2 diabetes and nondiabetic subjects lessened from I year before until 6 years after the start of oral antidiabetic therapy, reflected by decreasing attributable risks lot, diuretics, beta -blockers, calcium channel blockers, and cardiac and antithrombotic drugs. The difference in use of angiotensin-converting enzyme inhibitors and lipid-lowering drugs increased. Cardiovascular hospitalizations attributable to type 2 diabetes were similar to 50% in the years close to the start of oral antidiabetic treatment and decreased to similar to 33% in the following),cars. CONCLUSIONS - Although cardiovascular drug use and hospitalizations remained increased in patients with type 2 diabetes after the start of oral antidiabetic therapy, cardiovascular drug use attributable to type 2 diabetes decreased after the start of oral antidiabetic therapy, especially beta -blockers, whereas cardiovascular hospitalizations First decreased and then stabilized.