84 Circulating Vitamin D Levels and Frailty in the British Regional Heart Study: Cross Sectional and Prospective Associations

Introduction

Whether Vitamin D deficiency is linked to development of frailty, independent of other health conditions, is inconclusive. In the British Regional Heart Study we aimed to examine (1) cross sectional (CS) and prospective (PS) associations between Vitamin D levels and frailty; and (2) if these are mediated by conditions linked to low Vitamin D (diabetes, chronic obstructive pulmonary disease and inflammatory markers C-reactive protein & Interleukin-6).

Methods

Baseline (2010-2012) Vitamin D in men (71-92y) was categorised as deficiency (<12 ng/ml), insufficiency (12 - < 20 ng/ml) and sufficiency (≥20 ng/ml) states. Frailty, assessed at baseline and follow up (2014) was classified as robust, pre-frail or frail (score 0, 1-2, or ≥3 out of 5 Fried Frailty components respectively). Multinomial regression determined CS & PS relative risk ratios (RRR) of being pre-frail or frail, relative to robust. Adjustments were made for age, BMI, season, smoking, drinking habits, social class, Vitamin D/calcium supplements, mental/physical health and potential mediators.

Results

At baseline, 20% of 1494 men were frail and 25% deficient in Vitamin D. Unadjusted RRR of being frail (vs robust) was 3.16 [95% CI 2.16, 4.62] in men with Vitamin D<12ng/ml (reference ≥20ng/ml). Higher RRR persisted even after adjusting for covariates and potential mediating factors, [2.74; 95% CI 1.60, 4.69]. Of 977 men non-frail at baseline, 10% became frail. Men with Vitamin D <12ng/ml (reference ≥20ng/ml) had higher unadjusted RRR of becoming pre-frail [1.47; 95% CI 1.04, 2.09] and frail [2.14 95% CI 1.29, 3.56] (vs robust). While the PS association with pre-frailty was completely attenuated with covariate adjustment, higher RRR for frailty remained even in the fully adjusted model [2.07 95% CI 1.07, 4.00].

Conclusions

Vitamin D <12ng/ml was associated with prevalent & incident frailty in older British men, independent of disease/inflammatory states. Further research exploring Vit D therapy for improving frailty outcomes is needed.

Reference

1. Parry SW. JAGS;2016;64(11):2368–2373.

Mild hyponatremia, hypernatremia and incident cardiovascular disease and mortality in older men: A population-based cohort study

AIM

To examine the association between serum sodium concentration and incident major cardiovascular disease (CVD) outcomes and total mortality in older men.

METHODS AND RESULTS

A prospective study of 3099 men aged 60-79 years without a history of cardiovascular disease followed up for an average 11 years during which there were 528 major CVD events (fatal coronary heart disease [CHD] and non-fatal MI, stroke and CVD death) and 873 total deaths. A U shaped relationship was seen between serum sodium concentration and major CVD events and mortality. Hyponatremia (<136 mEq/L) and low sodium within the normal range (136-138 mEq/L) showed significantly increased risk of major CVD events and total mortality compared to men within the upper normal range (139-143 mEq/L) after adjustment for a wide range of confounders and traditional risk factors [adjusted HRs 1.55 (1.13,2.12) and 1.40 (1.14,1.72) for major CVD events respectively and 1.30 (1.02,1.66) and 1.30 (1.11,1.53) respectively for total mortality]. Hyponatremia was associated with inflammation, NT-proBNP, low muscle mass and alkaline phosphatase; these factors contributed to the increased total mortality associated with hyponatremia but did not explain the increased risk of CVD events associated with hyponatremia or low normal sodium concentration. Hypernatremia (≥145 mEq/L) was associated with significantly increased risk of CVD events and mortality due to CVD causes.

CONCLUSION

Mild hyponatremia even within the normal sodium range and hypernatremia are both associated with increased total mortality and major CVD events in older men without CVD which is not explained by known adverse CV risk factors.

Socioeconomic inequalities in coronary heart disease risk in older age: contribution of established and novel coronary risk factors

BACKGROUND

Evidence on socioeconomic inequalities in coronary heart disease (CHD) and their pathways in the elderly is limited. Little is also known about the contributions that novel coronary risk factors (particularly inflammatory/hemostatic markers) make to socioeconomic inequalities in CHD.

OBJECTIVES

To examine the extent of socioeconomic inequalities in CHD in older age, and the contributions (relative and absolute) of established and novel coronary risk factors.

METHODS

A population-based cohort of 3761 British men aged 60-79 years was followed up for 6.5 years for CHD mortality and incidence (fatal and non-fatal). Social class was based on longest-held occupation recorded at 40-59 years.

RESULTS

There was a graded relationship between social class and CHD incidence. The hazard ratio for CHD incidence comparing social class V (unskilled workers) with social class I (professionals) was 2.70 [95% confidence interval (CI) 1.37-5.35; P-value for trend = 0.008]. This was reduced to 2.14 (95% CI 1.06-4.33; P-value for trend = 0.11) after adjustment for behavioral factors (cigarette smoking, physical activity, body mass index, and alcohol consumption), which explained 38% of the relative risk gradient (41% of absolute risk). Additional adjustment for inflammatory markers (C-reactive protein, interleukin-6, and von Willebrand factor) explained 55% of the relative risk gradient (59% of absolute risk). Blood pressure and lipids made little difference to these estimates; results were similar for CHD mortality.

CONCLUSIONS

Socioeconomic inequalities in CHD persist in the elderly and are at least partly explained by behavioral risk factors; novel (inflammatory) coronary risk markers made some further contribution. Reducing inequalities in behavioral factors (especially cigarette smoking) could reduce these social inequalities by at least one-third.

Circulating inflammatory and hemostatic biomarkers are associated with risk of myocardial infarction and coronary death, but not angina pectoris, in older men

AIMS

The extent to which hemostatic and inflammatory biomarkers are related to angina pectoris as compared with myocardial infarction (MI) remains uncertain. We examined the relationship between a wide range of inflammatory and hemostatic biomarkers, including markers of activated coagulation, fibrinolysis and endothelial dysfunction and viscosity, with incident myocardial infarction (MI) or coronary heart disease (CHD) death and incident angina pectoris uncomplicated by MI or CHD death in older men.

METHODS

A prospective study of 3217 men aged 60-79 years with no baseline CHD (angina or MI) and who were not on warfarin, followed up for 7 years during which there were 198 MI/CHD death cases and 220 incident uncomplicated angina cases.

RESULTS

Inflammatory biomarkers [C-reactive protein (CRP), interleukin-6, fibrinogen], plasma viscosity and hemostatic biomarkers [von Willebrand factor (VWF) and fibrin D-dimer] were associated with a significant increased risk of MI/CHD death but not with uncomplicated angina even after adjustment for age and conventional risk factors. Adjustment for CRP attenuated the relationships between VWF, fibrin D-dimer and plasma viscosity with MI/CHD death. Comparisons of differing associations with risk of MI/CHD deaths and uncomplicated angina were significant for the inflammatory markers (P < 0.05) and marginally significant for fibrin D-dimer (P = 0.05). In contrast, established risk factors including blood pressure and high-density lipoprotein (HDL)-cholesterol were associated with both MI/CHD death and uncomplicated angina.

CONCLUSION

Circulating biomarkers of inflammation and hemostasis are associated with incident MI/CHD death but not incident angina uncomplicated by MI or CHD death in older men.

Serum matrix metalloproteinase-9 and coronary heart disease: a prospective study in middle-aged men

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) has a potential role in arterial plaque rupture, but its relation to risk of coronary heart disease (CHD) is uncertain.

AIM

To determine whether circulating levels of serum MMP-9 are prospectively related to the risk of CHD in the general population.

METHODS

We measured baseline MMP-9 levels in stored serum samples of subjects in a case-control study nested within a prospective study of 5661 men followed up for 16 years for CHD events (465 cases, 1076 controls).

RESULTS

MMP-9 values were associated with cigarette smoking, and with several inflammatory and haemostatic markers, but not with age, body mass index, blood pressure or lipid measurements. Men in the top third of baseline MMP-9 levels had an age-adjusted odds ratio (OR) for CHD of 1.37 (95% CI 1.04-1.82) compared with those in the bottom third. Adjustment for conventional risk factors (smoking in particular) reduced the odds ratio to borderline significance: OR 1.28 (95% CI 0.95-1.74), while additional adjustment for two markers of generalized inflammation, interleukin-6 and C-reactive protein, further attenuated the association: OR 1.13 (0.82-1.56).

CONCLUSION

Serum MMP-9 has a modest association with incident CHD in the general population, which is not independent of cigarette smoking exposure and circulating markers of generalized inflammation. MMP-9 is unlikely to be a clinically useful biomarker of CHD risk, but may still play a role in the pathogenesis of CHD.

The value of gamma-glutamyltransferase in cardiovascular risk prediction in men without diagnosed cardiovascular disease or diabetes

AIMS

We have examined the relationship between gamma-glutamyltransferase (GGT) and major coronary heart disease (CHD) and stroke events and cardiovascular mortality in men free of cardiovascular disease (CVD).

METHODS

A prospective study of 6997 men aged 40-59 with no history of CVD (CHD or stroke) or diabetes drawn from general practices in 24 British towns and followed up for 24 years.

RESULTS

GGT was significantly and positively associated with increased risk of fatal (but not non-fatal CHD events), major stroke events and total CVD mortality after adjustment for established CVD risk factors. Risk of fatal CHD and CVD mortality was only elevated in the top quarter (22IU/L); risk of stroke tended to increase with increasing GGT. The adjusted relative risks (Q4 vs. Q1) were 1.43 (1.09,1.84) for fatal CHD events, 1.56 (1.20,2.04) for stroke incidence and 1.40 (1.16,1.70) for CVD mortality. When stratified by age groups stronger associations were seen between GGT and CVD mortality in the younger men (<55 years) (p=0.01 for interaction). GGT significantly predicted CVD outcomes especially in those at low and medium CHD risk based on Framingham risk score (FRS).

CONCLUSION

Elevated GGT is associated with significantly increased risk of stroke, fatal CHD events and CVD mortality independent of established CVD risk factors and may be a useful additional marker for long-term CVD risk.

Effects of older age on fibrin D-dimer, C-reactive protein, and other hemostatic and inflammatory variables in men aged 60-79 years

BACKGROUND

Previous studies have suggested that several hemostatic and inflammatory variables, which are risk predictors for arterial or venous thrombosis, increase with age. However, there is a lack of data from large population studies for reliable estimates of reference ranges.

OBJECTIVES

To establish reliable reference ranges of hemostatic and inflammatory variables for 5-year age groups in older men and their implications for pathogenesis and diagnosis.

PATIENTS AND METHODS

A total of 3861 men aged 60-79 years at the 20 years follow-up of the British Regional Heart Study.

RESULTS

Several variables increased with age. The greatest median increases between 60-64 and 75-79 years age groups were observed for fibrin D-dimer (91%) and C-reactive protein (CRP) (57%). Significant median increases were also observed for von Willebrand factor antigen (23%), tissue plasminogen activator antigen (11%), factor VIII (10%), and fibrinogen (8%). In contrast, levels of classical cardiovascular risk factors neither decreased nor increased substantially with age, with the exception of systolic blood pressure (median increase 10%).

CONCLUSIONS

The exponential increases in risk of arterial and venous thrombotic events in men between age 60 and 79 years (when most such events occur) may be related in part to increasing activation of blood coagulation, fibrinolysis, and inflammation; possibly related to the increasing inflammatory burden of both atherosclerotic and non-vascular disease. These increases also have implications for diagnosis of suspected acute venous thromboembolism (D-dimer), and recently proposed screening for prediction of coronary heart disease risk and detection of occult disease (CRP).

Cardiovascular disease incidence and mortality in older men with diabetes and in men with coronary heart disease

OBJECTIVE

To examine the relation of diabetes and coronary heart disease (CHD; myocardial infarction (MI) or angina) to the incidence of major CHD and stroke events and total mortality.

METHODS

Prospective study of 5934 men aged 52-74 years followed up for 10 years. The men were divided into five groups according to their diabetes and CHD status.

RESULTS

During the follow up there were 662 major CHD events, 305 major stroke events, and 1357 deaths from all causes (637 cardiovascular disease (CVD) deaths, 417 CHD deaths). Men with diabetes had significantly increased cardiovascular and total mortality risk compared with non-diabetic men with no CHD but lower risk than men with prior MI only. The adjusted relative risk for CHD deaths was 2.82 (95% confidence interval (CI) 1.85 to 4.28) in men with diabetes only, 2.12 (95% CI 1.53 to 2.93) in men with angina only, 3.91 (95% CI 3.07 to 4.99) in men with MI, and 8.93 (95% CI 6.13 to 12.99) in men with both diabetes and CHD. Case fatality among men with diabetes only was similar to those with prior MI only. CHD and CVD mortality increased with increasing duration of diabetes with risk eventually approaching that of patients with MI without diabetes.

CONCLUSION

Men with diabetes only have a CVD risk intermediate between men with angina and men with prior MI. Their absolute risk is high and the prognosis for diabetic patients who develop CHD is extremely poor.

Insulin resistance, haemostatic and inflammatory markers and coronary heart disease risk factors in Type 2 diabetic men with and without coronary heart disease

AIMS/HYPOTHESIS

We have examined markers of haemostasis and inflammation in men with diabetes, coronary heart disease (CHD) or both, and assessed their associations with insulin resistance in men with Type 2 diabetes.

METHODS

The study was carried out in 4066 British men aged 60 to 79 years who were not on warfarin or insulin, of whom there were 426 men with prevalent Type 2 diabetes and 842 with prevalent CHD.

RESULTS

Men with Type 2 diabetes were more likely to have multiple risk factors and higher levels of haemostatic and inflammatory markers than men without, irrespective of CHD status. Compared with men with CHD only, men with diabetes only showed increased levels of tissue plasminogen activator antigen, increased plasma and blood viscosity, and increased levels of coagulation factors VII, VIII and IX. They also had dyslipidaemia. In men with diabetes, increased insulin resistance (homeostasis model assessment, HOMA) was associated with increased levels of haemostatic markers and dyslipidaemia. The prevalence of CHD increased significantly with increasing tertiles of HOMA (adjusted odds ratio 1.32 [95% CI: 0.72-2.42] in the second, and 1.70 [95% CI: 0.92-3.44] in the third tertile; p=0.04 for trend).

CONCLUSIONS/INTERPRETATION

Increased insulin resistance among men with Type 2 diabetes is associated with increased prevalence of CHD and of activated haemostasis and dyslipidaemia. Reducing insulin resistance in men with diabetes may reduce their tendency to develop thrombosis and hence CHD risk.

Tissue plasminogen activator antigen and coronary heart disease Prospective study and meta-analysis

AIMS

To determine whether circulating tissue plasminogen activator (t-PA) antigen concentrations are prospectively related to risk of coronary heart disease (CHD) in the general population.

METHODS AND RESULTS

We measured baseline concentrations of t-PA antigen in the stored serum samples of 606 CHD cases and 1227 controls 'nested' in a prospective cohort of 5661 men monitored for 16 years, and conducted a meta-analysis of previous relevant studies to place our findings in context. Tissue plasminogen activator antigen values were strongly correlated with several vascular risk factors, including serum lipids, body mass index, alcohol consumption, and markers of systemic inflammation. In a comparison of men in the top third compared with those in the bottom third of baseline t-PA antigen values, the odds ratio for CHD was 2.20 (95% confidence interval (CI) 1.70-2.85) after adjustment for age and town only, but this fell to 1.48 (1.09-2.01) after further adjustment. Analysis of t-PA as a continuous variable gave similar results. Similarly, when published information on all seven available prospective cohort studies in general populations (2119 cases and 8832 controls in total) was synthesized, the combined odds ratio was 2.18 (1.77-2.69) after adjustment for age and sex only, and this fell to 1.47 (1.19-1.81) after further adjustment.

CONCLUSION

Although there is a statistically significant association between circulating concentrations of t-PA antigen and subsequent CHD, additional studies are needed to determine to what extent this is independent from more established risk factors.

von Willebrand factor and coronary heart disease: prospective study and meta-analysis

AIMS

To determine whether circulating von Willebrand factor concentrations are prospectively related to risk of coronary heart disease in the general population.

METHODS AND RESULTS

We measured baseline von Willebrand factor values in the stored serum samples of 625 men with major coronary events and in 1266 controls 'nested' in 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 16 years for fatal coronary heart disease and non-fatal myocardial infarction. We conducted a meta-analysis of previous relevant studies to place our results in context. Men in the top third of baseline von Willebrand factor values (tertile cutoff >126 IU.dl(-1)) had an odds ratio for coronary heart disease of 1.83 (95% confidence interval 1.43-2.35; 2P <0.0001) compared with those in the bottom third (tertile cutoff <90 IU.dl(-1)), after adjustments for age and town. The odds ratio was little changed after further adjustment for risk factors (1.82, 95% CI 1.37-2.41), and was not significantly different in an analysis restricted to the 404 cases and 1007 controls without baseline evidence of coronary heart disease (odds ratio 1.53, 95% CI 1.10-2.12). A meta-analysis of all relevant population-based prospective studies (including the present study) yielded a combined odds ratio of 1.5 (95% CI 1.1-2.0). von Willebrand factor values were strongly correlated with Helicobacter pylori seropositivity and circulating concentrations of C-reactive protein (2 P<0.0001 for each), but not with smoking, blood lipids, or most other measured risk factors.

CONCLUSION

Though circulating von Willebrand factor concentrations may be associated with incident coronary heart disease, further studies are needed to determine the extent to which this is causal.

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.

Chlamydia pneumoniae IgA titres and coronary heart disease; prospective study and meta-analysis

AIMS

To examine associations between Chlamydia pneumoniae IgA titres and incident coronary heart disease, and to compare them with associations previously reported between C. pneumoniae IgG titres and coronary heart disease.

METHODS AND RESULTS

We measured serum concentrations of C. pneumoniae IgA antibodies in 502 coronary heart disease cases and in 1005 age- and town-matched controls 'nested' in a community-based prospective study of 5661 British men (mean follow-up in controls, 16 years), and conducted a meta-analysis of published prospective studies to place our findings in context. Two hundred and twenty-one (44%) of the cases were in the top third of C. pneumoniae IgA titres compared with 336 (33%) of the controls, yielding an odds ratio for coronary heart disease of 1.84 (95% confidence interval 1.40-2.43) which was largely unchanged after adjustment. In aggregate, the present study and nine previously reported prospective studies of C. pneumoniae IgA titres involved 2283 cases, yielding a combined odds ratio for coronary heart disease of 1.25 (1.03-1.53), with no significant heterogeneity among the ten studies (chi(2)9=7.8; P>0.1). This combined odds ratio is compatible with that previously reported for C. pneumoniae IgG titres and coronary heart disease (1.15, 0.97-1.36).

CONCLUSION

Neither C. pneumoniae IgA titres nor IgG titres are strongly predictive of coronary heart disease in the general population.

Soluble adhesion molecules and prediction of coronary heart disease: a prospective study and meta-analysis

BACKGROUND

Previous studies have suggested that circulating concentrations of soluble adhesion molecules are useful predictors of risk of coronary heart disease (CHD). Larger studies are needed, however, to test this hypothesis.

METHODS

We measured serum concentrations of four soluble cell adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], E-selectin, and P-selectin) in the stored baseline serum samples of 643 men with coronary heart disease and 1278 controls nested in a prospective sutdy of 5661 men who were monitored for 16 years. We also did a meta-analysis of previous relevant studies to place our findings in context.

RESULTS

Concentrations of soluble adhesion molecules were significantly associated with one another, with other markers of inflammation, and with some classic coronary risk factors. For ICAM-1, the odds ratio for CHD was 1.68 (95% CI 1.32-2.14) in a comparison of men in the top third with those in the bottom third of baseline measurements after adjustments for age and town. This decreased to 1.11 (0.75-1.64) after adjustment for some classic coronary risk factors and indicators of socioeconomic status. For the three other cell adhesion molecules, the odds ratios for CHD, first adjusted for age and town only, and then additionally adjusted for other risk factors, were: VCAM-1: 1.26 (0.99-1.61) and 0.96 (0.66-1.40); E-selectin: 1.27 (1.00-1.61) and 1.13 (0.78-1.62); and P-selectin: 1.23 (0.96-1.56) and 1.20 (0.81-1.76).

INTERPRETATION

The measurement of these adhesion molecules is unlikely to add much predictive information to that provided by more established risk factors.

Fibrin D-dimer and coronary heart disease: prospective study and meta-analysis

BACKGROUND

It is unknown whether modest increases of fibrin D-dimer, a circulating marker of fibrin turnover, are relevant to coronary heart disease (CHD) in the general population.

METHODS AND RESULTS

We measured serum concentrations of D-dimer antigen in the stored baseline blood samples of 630 CHD cases and 1269 controls "nested" in a prospective cohort of 5661 men who were monitored for 16 years, and we conducted a meta-analysis of previous relevant studies to place our findings in context. In a comparison of men in the top third compared with those in the bottom third of baseline fibrin D-dimer values (tertile cutoffs, >94 versus <49 ng/mL), the odds ratio for CHD was 1.67 (95% CI, 1.31 to 2.13; P<0.0001) after adjustments for age and town. The odds ratio increased slightly after further adjustment for smoking, other classic risk factors, and indicators of socioeconomic status (1.79; 95% CI, 1.36 to 2.36). Strong correlations were observed of fibrin D-dimer values with circulating concentrations of C-reactive protein and serum amyloid A protein but not with smoking, blood lipids, blood pressure, and other risk factors.

CONCLUSION

Although there may be an association between circulating D-dimer values and CHD, further studies are needed to determine the extent to which this is causal.

The effect of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene on homocysteine levels in elderly men and women from the British regional heart study

Total blood levels of homocysteine (tHcy) have been shown to depend on both environmental and genetic factors, and to be associated with the risk of developing atherosclerosis with its complications of coronary heart disease (CHD) and stroke. In this study, 408 men and 346 women from two towns, Dewsbury and Maidstone were examined for tHcy levels and genotyped for the C677T and the A1298C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene. Blood tHcy was significantly higher in men from the CHD high risk town of Dewsbury (12.7 micromol/l) than in the low CHD risk town of Maidstone (11.5 micromol/l) P<0.001, but not in women (10.7 vs. 10.5 micromol/l), with women in both towns, thus, showing significantly lower tHcy than men. There was no difference between towns in folate or vitamin B12 levels but the conventional inverse relationship with tHcy was seen. Smoking men and women from both towns had significantly higher tHcy and lower folate levels than non-smoking individuals (P<0.001). The frequency of the 677T allele in Dewsbury was 0.35 (95% CI; 0.32-0.39) compared with 0.29 (95% CI; 0.26-0.32) in Maidstone (P<0.01). Similar frequency difference of borderline statistical significance was seen both for men (P=0.054) and women (P=0.048) in both the towns, suggesting a true regional frequency difference. The effect of the 677T on tHcy was highly significant in the group as a whole with the most profound effect seen in men (12.0 micromol/l for CC vs. 14.1 micromol/l for TT, P<0.001). By contrast, there was no significant effect of the A1298C polymorphism on tHcy, folate or vitamin B12 levels, with no evidence for an interaction with the C677T genotype. The regional differences in tHcy levels were still present after the adjustment for folate and vitamin B12 levels, smoking and the effect of the C677T polymorphism. This suggests that there may be other unidentified factors, either environmental or genetic, affecting tHcy levels, and thus potentially having an impact on the risk of developing hyperhomocysteinaemia and CHD. These observations may have a bearing on regional differences in tHcy levels and the variation in CHD risk between regions in the UK.

Twenty year follow-up of a cohort based in general practices in 24 British towns

BACKGROUND

A national prospective study of cardiovascular disease (CVD) was set up in 1978 to explain the reasons for the marked geographical variation in CVD rates in Great Britain. A total of 7735 males, aged 40-59 years (born between 1919 and 1939) randomly selected from one general practice age-sex register in each of 24 towns, responded to a screening invitation from their general practitioner (GP) and were examined in 1978-1980. We describe the methods used and the contact maintained after following a cohort for 20 years.

METHODS

The established system of patient registration with a GP was used for tracing and maintaining contact with a low-mobility cohort through local area health authority networks and the National Health Service Central Register.

RESULTS

By 31 December 1997, there were 1856 recorded deaths (14 known to have occurred abroad), 66 emigrations/ living overseas/lost from follow-up. In addition, 1500 study subjects had registered with new GPs who, every 2 years, provided information on both fatal and non-fatal cardiovascular events to complement information supplied by the original practices. Information was obtained on all cardiovascular events and deaths for 99.5 per cent of the surviving sample. Questionnaires mailed to surviving subjects 5 years after recruitment (1983-1985) and again in November 1992 and 1996 were returned by 98, 90 and 88 per cent, respectively, providing information on lifestyle changes, new cardiovascular symptoms and new diagnoses.

CONCLUSION

Using the NHSCR framework for primary care registration procedures, maximum follow-up has been maintained. Brief and structured enquiry forms have gained and maintained co-operation from subjects and their GPs with considerable success. Mortality reporting from dual sources identified 5 per cent more cases.

Low grade inflammation and coronary heart disease: prospective study and updated meta-analyses

OBJECTIVE

To assess associations between baseline values of four different circulating markers of inflammation and future risk of coronary heart disease, potential triggers of systemic inflammation (such as persistent infection), and other markers of inflammation.

DESIGN

Nested case-control comparisons in a prospective, population based cohort.

SETTING

General practices in 18 towns in Britain.

PARTICIPANTS

506 men who died from coronary heart disease or had a non-fatal myocardial infarction and 1025 men who remained free of such disease until 1996 selected from 5661 men aged 40-59 years who provided blood samples in 1978-1980.

MAIN OUTCOME MEASURES

Plasma concentrations of C reactive protein, serum amyloid A protein, and serum albumin and leucocyte count. Information on fatal and non-fatal coronary heart disease was obtained from medical records and death certificates.

RESULTS

Compared with men in the bottom third of baseline measurements of C reactive protein, men in the top third had an odds ratio for coronary heart disease of 2.13 (95% confidence interval 1.38 to 3.28) after age, town, smoking, vascular risk factors, and indicators of socioeconomic status were adjusted for. Similar adjusted odds ratios were 1.65 (1.07 to 2.55) for serum amyloid A protein; 1.12 (0.71 to 1.77) for leucocyte count; and 0.67 (0.43 to 1.04) for albumin. No strong associations were observed of these factors with Helicobacter pylori seropositivity, Chlamydia pneumoniae IgG titres, or plasma total homocysteine concentrations. Baseline values of the acute phase reactants were significantly associated with one another (P<0.0001), although the association between low serum albumin concentration and leucocyte count was weaker (P=0.08).

CONCLUSION

In the context of results from other relevant studies these findings suggest that some inflammatory processes, unrelated to the chronic infections studied here, are likely to be involved in coronary heart disease.

Chlamydia pneumoniae IgG titres and coronary heart disease: prospective study and meta-analysis

OBJECTIVE

To examine the association between coronary heart disease and serum markers of chronic Chlamydia pneumoniae infection.

DESIGN

"Nested" case-control analysis in a prospective cohort study and an updated meta-analysis of previous relevant studies.

SETTING

General practices in 18 towns in Britain.

PARTICIPANTS

Of the 5661 men aged 40-59 who provided blood samples during 1978-80, 496 men who died from coronary heart disease or had non-fatal myocardial infarction and 989 men who had not developed coronary heart disease by 1996 were included.

MAIN OUTCOME MEASURES

IgG serum antibodies to C pneumoniae in baseline samples; details of fatal and non-fatal coronary heart disease from medical records and death certificates.

RESULTS

200 (40%) of the 496 men with coronary heart disease were in the top third of C pneumoniae titres compared with 329 (33%) of the 989 controls. The corresponding odds ratio for coronary heart disease was 1.66 (95% confidence interval 1.25 to 2.21), which fell to 1.22 (0.82 to 1.82) after adjustment for smoking and indicators of socioeconomic status. No strong associations were observed between C pneumoniae IgG titres and blood lipid concentrations, blood pressure, or plasma homocysteine concentration. In aggregate, the present study and 14 other prospective studies of C pneumoniae IgG titres included 3169 cases, yielding a combined odds ratio of 1. 15 (0.97 to 1.36), with no significant heterogeneity among the separate studies (chi(2)=10.5, df=14; P>0.1).

CONCLUSION

This study, together with a meta-analysis of previous prospective studies, reliably excludes the existence of any strong association between C pneumoniae IgG titres and incident coronary heart disease. Further studies are required, however, to confirm or refute any modest association that may exist, particularly at younger ages.

High prevalence of potentially virulent strains of Helicobacter pylori in the general male British population

BACKGROUND

Strains of Helicobacter pylori that express the cytotoxin associated gene product A (CagA) may be more strongly associated with serious gastric diseases, such as gastric cancer and peptic ulceration, than other strains. Data, however, are sparse on the prevalence, risk factors, and other correlates of these strains in the general population.

AIM

To characterise aspects of the seroepidemiology of CagA(+) strains of H pylori in the general British population.

METHODS

We measured serum IgG antibodies to mixed H pylori antigens and separately to CagA in 1025 men aged 40-59 years who were randomly selected from a larger group of participants in a community based survey conducted in 18 different British towns.

RESULTS

Overall, 44% (95% confidence interval 41-47%) of the men were seropositive to CagA antibodies, representing about 61% (57-65%) of the men seropositive to mixed antigen H pylori. The risk factors for seropositivity to CagA antibodies were similar to those for seropositivity to mixed antigen H pylori, apart from an increased prevalence of reported bedroom sharing in childhood (p<0.01).

CONCLUSION

In a nationwide study of potentially virulent H pylori strains, there was a high prevalence of the infection, with some evidence that acquisition of such strains might occur earlier in life than other strains.

Prospective study of potentially virulent strains of Helicobacter pylori and coronary heart disease in middle-aged men

BACKGROUND

Studies are needed to test claims that potentially virulent strains of Helicobacter pylori are more strongly related to coronary heart disease (CHD) than are other strains.

METHODS AND RESULTS

We measured serum IgG antibodies to mixed H pylori antigens and separately to the virulence-associated H pylori antigen CagA (cytotoxin-associated gene product A) in 505 CHD cases and in 1025 age-matched controls "nested" in a prospective study of 7735 British men (mean duration of follow-up in controls, 16 years). Of the 505 cases, 401 (79%) were seropositive for H pylori antibodies compared with 740 (72%) of the 1025 controls, yielding an odds ratio for CHD of 1.55 (95% CI 1.19 to 2.03), which fell to 1.30 (95% CI 0.88 to 1. 90) after adjustments were made for standard vascular risk factors and indicators of socioeconomic status. Of the CHD cases, 240 (48%) were seropositive for IgG antibodies to CagA compared with 450 (44%) of the controls. When CagA-seropositive individuals were compared with H pylori-seronegative individuals, the odds ratio for CHD was 1. 42 (95% CI 1.06 to 1.91), which fell to 1.10 (95% CI 0.71 to 1.71) after adjustments. In an analysis restricted to the 1141 (75%) H pylori-seropositive participants, the odds ratio for CHD was 1.0 (95% CI 0.78 to 1.29) in CagA-seropositive men. No strong associations were observed between H pylori seropositivity and blood lipids, blood pressure, markers of systemic inflammation, or plasma homocysteine.

CONCLUSIONS

H pylori infection is not strongly related to the incidence of CHD in late middle-aged men, and CagA-positive strains appear to be no more strongly related to the disease than other strains. However, further studies are required to confirm or refute the existence of any moderate associations, particularly at younger ages.

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 micromol/l) than in controls (13.5 micromol/l), a proportional difference of 5.5% (95% confidence interval (CI) -0.02% to 10.8%, p = 0.06). 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; p = 0.05). The relation was particularly marked in the top fifth of the total homocysteine distribution (values >16.5 micromol/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 micromol/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 (r = 0.43, p = 0.08).

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.