A. Thomson

Serum total homocysteine and coronary heart disease: prospective study in middle aged men

OBJECTIVES To examine the prospective relation between total homocysteine and major coronary heart disease events. DESIGN A nested case–control study carried out within the British regional heart study, a prospective investigation of cardiovascular disease in men aged 40–59 years at entry. Serum total homocysteine concentrations were analysed retrospectively and blindly in baseline samples from 386 cases who had a myocardial infarct during 12.8 years of follow up and from 454 controls, frequency matched by age and town. RESULTS Geometric mean serum total homocysteine was slightly higher in cases (14.2 μmol/l) than in controls (13.5 μmol/l), a proportional difference of 5.5% (95% confidence interval (CI) −0.02% to 10.8%, pu2009=u20090.06). Age adjusted risk of myocardial infarction increased weakly with log total homocysteine concentration; a 1 SD increase in log total homocysteine (equivalent to a 47% increase in total homo cysteine) was associated with an increase in odds of myocardial infarction of 1.15 (95% CI 1.00 to 1.32; pu2009=u20090.05). The relation was particularly marked in the top fifth of the total homocysteine distribution (values >16.5 μmol/l), which had an odds ratio of 1.77 (95% CI 1.28 to 2.42) compared with lower levels. Adjustment for other risk factors had little effect on these findings. Total homocysteine concentrations more than 16.5 μmol/l accounted for 13% of the attributable risk of myocardial infarction in this study population. Serum total homocysteine among control subjects varied between towns and was correlated with town standardised mortality ratios for coronary heart disease (ru2009=u20090.43, pu2009=u20090.08). CONCLUSIONS Serum total homocysteine is prospectively related to increased coronary risk and may also be related to geographical variation in coronary risk within Britain. These results strengthen the case for trials of total homocysteine reduction with folate.

Comparative analysis of genome-wide association studies signals for lipids, diabetes, and coronary heart disease: Cardiovascular Biomarker Genetics Collaboration

Aims To evaluate the associations of emergent genome-wide-association study-derived coronary heart disease (CHD)-associated single nucleotide polymorphisms (SNPs) with established and emerging risk factors, and the association of genome-wide-association study-derived lipid-associated SNPs with other risk factors and CHD events. Methods and results Using two case–control studies, three cross-sectional, and seven prospective studies with up to 25 000 individuals and 5794 CHD events we evaluated associations of 34 genome-wide-association study-identified SNPs with CHD risk and 16 CHD-associated risk factors or biomarkers. The Ch9p21 SNPs rs1333049 (OR 1.17; 95% confidence limits 1.11–1.24) and rs10757274 (OR 1.17; 1.09–1.26), MIA3 rs17465637 (OR 1.10; 1.04–1.15), Ch2q36 rs2943634 (OR 1.08; 1.03–1.14), APC rs383830 (OR 1.10; 1.02, 1.18), MTHFD1L rs6922269 (OR 1.10; 1.03, 1.16), CXCL12 rs501120 (OR 1.12; 1.04, 1.20), and SMAD3 rs17228212 (OR 1.11; 1.05, 1.17) were all associated with CHD risk, but not with the CHD biomarkers and risk factors measured. Among the 20 blood lipid-related SNPs, LPL rs17411031 was associated with a lower risk of CHD (OR 0.91; 0.84–0.97), an increase in Apolipoprotein AI and HDL-cholesterol, and reduced triglycerides. SORT1 rs599839 was associated with CHD risk (OR 1.20; 1.15–1.26) as well as total- and LDL-cholesterol, and apolipoprotein B. ANGPTL3 rs12042319 was associated with CHD risk (OR 1.11; 1.03, 1.19), total- and LDL-cholesterol, triglycerides, and interleukin-6. Conclusion Several SNPs predicting CHD events appear to involve pathways not currently indexed by the established or emerging risk factors; others involved changes in blood lipids including triglycerides or HDL-cholesterol as well as LDL-cholesterol. The overlapping association of SNPs with multiple risk factors and biomarkers supports the existence of shared points of regulation for these phenotypes.

Low prevalence of lipid lowering drug use in older men with established coronary heart disease

Objective: To determine the prevalence and correlates of lipid lowering drug use among older British men with established coronary heart disease (CHD). Design: Cross sectional survey within a cohort study (British regional heart study) carried out at 20 years of follow up in 1998–2000. Setting: General practices in 24 British towns. Participants: 3689 men aged 60–75 years (response rate 76%). Main outcome measures: Diagnoses of myocardial infarction and angina based on detailed review of general practice records. Lipid lowering drug use and blood cholesterol concentrations ascertained at 20 year follow up examination. Results: Among 286 men with definite myocardial infarction, 102 (36%) were taking a lipid lowering drug (93 (33%) a statin); among 360 men with definite angina without myocardial infarction, 84 (23%) were taking a lipid lowering drug (78 (21%) a statin). Most men with documented CHD who were not receiving a lipid lowering drug had a total cholesterol concentration of 5.0 mmol/l or more (87% of those with myocardial infarction, 82% with angina). Fewer than half of men with CHD receiving a statin had a total cholesterol concentration below 5.0 mmol/l (45% of those with myocardial infarction and 47% of those with angina). Only one third of the men taking a statin were receiving trial validated dosages. Among men with CHD, a history of revascularisation, more recent diagnosis, and younger age at diagnosis were associated with a higher probability of receiving lipid lowering drug treatment. Conclusion: Among patients with established CHD, the prevalence of lipid lowering drug use remains low and statin regimens suboptimal. Major improvements in secondary prevention are essential if the benefits of statins are to be realised.

Interleukin 18 and coronary heart disease: Prospective study and systematic review

Aim Previous studies suggest that circulating levels of interleukin-18 (IL-18) may be prospectively related to risk of coronary heart disease (CHD) in the general population. We report new data from the largest prospective study to date, which are combined with data from all published prospective studies in a meta-analysis. Methods We measured baseline IL-18 levels in stored serum samples of subjects from a case–control study nested within a prospective study of 5661 men aged 40–59 years recruited from general practices in 18 British towns in 1978–1980 and followed-up for up to 16 years (median time to event 8.4 years) for fatal CHD and non-fatal myocardial infarction (595 cases, 1238 controls). Results IL-18 concentrations were strongly related to cigarette smoking, triglyceride, HDL-cholesterol (inversely) and to circulating levels of several inflammatory and haemostatic markers. Men in the top third of baseline IL-18 levels had an age-adjusted odds ratio (OR) for CHD of 1.55 (95% CI 1.21, 1.98) compared with those in the lowest third; this was reduced to 1.30 (95% CI 0.99, 1.69) after additional adjustment for vascular risk factors and 1.12 (95% CI 0.84, 1.49) after further adjustment for CRP and IL-6. In meta-analyses of CVD, associations (or effect sizes) were consistent between studies; RRs were 1.63 (95% CI 1.46, 1.82) after age adjustment, 1.39 (95% CI 1.24, 1.55) after additional risk factor adjustment and 1.34 (95% CI 1.17, 1.54) after additional adjustment for inflammatory markers. Conclusions Circulating IL-18 is prospectively and independently associated with CVD risk.

Prospective study of matrix metalloproteinase-9 and risk of myocardial infarction and stroke in older men and women

Objectives The endopeptidase matrix metalloproteinase-9 (MMP-9) is implicated in atherosclerotic plaque rupture. We investigate prospective associations between MMP-9 and MI or stroke in an older general population cohort, accounting for established and novel cardiovascular risk factors. Methods Baseline serum MMP-9 was measured in incident MI (n = 368) and stroke (n = 299) cases and two controls per case, ‘nested’ in prospective studies of 4252 men and 4286 women aged 60–79 years, sampled from General Practices in Britain in 1998–2000, with 7-year follow-up for fatal and non-fatal MI and stroke. Results Geometric mean MMP-9 was 528 ng/mL (IQR 397, 743) in MI cases compared to 501 ng/mL (IQR 370, 743) in controls, p = 0.10. Participants in the top compared to bottom third of MMP-9 levels had an age-adjusted odds ratio for MI of 1.53 (95% CI 1.09, 2.13), which attenuated to 1.18 (95% CI 0.81, 1.70) after adjustment for established and novel cardiovascular risk factors. There was weak evidence that OR differed according to pre-existing CVD; the OR for MI in 187 participants with pre-existing CVD was 2.20 (1.04, 4.64) and 1.24 (0.84, 1.82) in 715 participants without (LR test for interaction p = 0.06). Geometric mean MMP-9 levels were higher in stroke cases than controls; 522 ng/mL (IQR 363, 673) vs 487 (IQR 393, 704), p = 0.045; however adjustments similarly attenuated the associations. Conclusions While serum MMP-9 is univariately associated with risk of MI and stroke, it is not a strong independent risk marker for either.

Inequalities in coronary revascularisation during the 1990s: evidence from the British regional heart study

Objective: To investigate the influence of age and social circumstances on probability of revascularisation among British men. Design: Prospective population based study Setting: 24 medium sized British towns, none of which contained a hospital undertaking coronary artery bypass surgery. Subjects: 5814 surviving participants of the BRHS (British regional heart study), aged 52–73 years, with no history of revascularisation when responding to a questionnaire in November 1992. Main outcomes: Incident coronary revascularisations, as documented in general practitioner records, over the following 7.1 years and coronary angiography investigations reported by men in a further questionnaire in November 1996. Results: 160 men underwent at least one revascularisation during this period (4.2/1000 person-years). In multifactorial analysis, which included adjustment for incidence of major coronary heart disease or angina, a lower incidence of revascularisation was found among men aged over 65 years in November 1992 (hazard ratio 0.62, 95% confidence interval (CI) 0.44 to 0.87), among men with manual occupations (0.73, 95% CI 0.53 to 1.02), among men living in households possessing no car (0.44, 95% CI 0.24 to 0.80) or one car (0.60, 95% CI 0.42 to 0.87) compared with two or more cars, among council tenants (0.49, 95% CI 0.25 to 0.97), and among men living outside southern England (0.71, 95% CI 0.51 to 0.99). Only car ownership was related to the incidence of diagnostic angiography: the odds ratio for angiography for those owning fewer than two cars was 0.62 (95% CI 0.42 to 0.89). Conclusion: During the 1990s, there were major inequalities in the probability of undergoing coronary revascularisation between British men according to socioeconomic status, age, and geographic location.

Prevalence of undiagnosed Type 2 diabetes and impaired fasting glucose in older British men and women.

Aimu2003 To estimate the prevalence of undiagnosed diabetes and impaired fasting glucose in older British men and women, using the 1999 World Health Organization (WHO) thresholds based on fasting glucose measurements.

Circulating TNFα levels in older men and women do not show independent prospective relations with MI or stroke

Background Tumour necrosis factor alpha (TNFα) is a pro-inflammatory cytokine implicated in atherosclerotic plaque formation. We investigated whether circulating TNFα is prospectively associated with myocardial infarction (MI) or stroke in the older general population, independently of established cardiovascular risk factors and other inflammatory markers related to CHD risk. Methods We measured baseline TNFα concentrations in stored serum samples of 362 incident MI and 299 incident stroke cases and controls (2 per case, frequency matched by age, gender and town) who were ‘nested’ in parallel prospective studies of 4252 men and 4286 women aged 60–79 years assessed in general practices in 24 British towns in 1998–2000 and followed up for an average 7 years for fatal and non-fatal MI and stroke. Results TNFα levels were 11.4% (95% CI 9.5, 13.3%) higher among MI cases than controls; geometric mean 1.84 pg/mL compared to 1.63 pg/mL, p (difference) < 0.001. Participants in the top third of baseline TNFα levels had an age-adjusted odds ratio (OR) for MI of 1.75 (95%CI 1.22, 2.49) compared with those in the bottom third, which was reduced to 1.47 (95%CI 1.01, 2.14) after adjustment for established cardiovascular risk factors. However, further adjustment for C-reactive protein and interleukin-6 abolished the association OR 1.33 (95% CI 0.91, 1.66) and the linear trend. Excluding subjects with pre-existing CVD did not materially affect results. No significant association between TNFα and stroke was observed. Conclusions This study suggests that TNFα is not a strong independent risk marker for MI, and is not associated with risk of stroke.

20-Year trends in major coronary risk factors in older British men: assessing the impact of medication use

Favourable trends in blood pressure (BP) and blood lipids have contributed to the falling incidence of coronary heart disease (CHD) in recent decades. The role of medication in the BP and blood lipid trends is unknown.nnTo investigate the impact of medication on 20-year trends in BP and blood lipids in older British men.nnLongitudinal study.nn24 British towns.nn4231 men from a socially and geographically representative cohort of older British men, examined at baseline (1978–80, aged 40–59 years) and …