Acute myocardial infarction (AMI) in Finland--baseline data from the FINMONICA AMI register in 1983-1985

Socioeconomic position, John Henryism, and incidence of acute myocardial infarction in Finnish men

Previous cross-sectional studies examining whether John Henryism (JH), or high-effort coping with socioeconomic adversity, potentiates the inverse association between socioeconomic position (SEP) and cardiovascular health have focused mainly on hypertension in African Americans. We conducted the first longitudinal test of this hypothesis on incident acute myocardial infarction (AMI) using data from the Kuopio Ischemic Heart Disease Risk Factor Study in Finland (N = 1405 men, 42-60 years). We hypothesized that the expected inverse gradient between SEP and AMI risk would be stronger for men scoring high on JH than for those scoring low. John Henryism was measured by a Finnish version of the JH Scale for Active Coping. Four different measures of SEP were used: childhood SEP, education, income, and occupation. AMI hazard ratios (HR) by SEP and JH were estimated using COX proportional hazard models, before and after adjustment for study covariates. 205 cases of AMI occurred over a median of 14.9 years. Men employed in lower rank (farmer, blue-collar) occupations who scored high on JH had significantly higher age-adjusted risks of AMI than men in higher rank (white-collar) occupations (HR = 3.14, 95% CI: 1.65-5.98 for blue collar; HR = 2.33, 95% CI: 1.04-5.22 for farmers) who also scored high on JH. No socioeconomic differences in AMI were observed for men who scored low on JH (HR = 1.36, 95% CI: 0.74-2.47 for blue collar; HR = 0.93, 95% CI: 0.59-1.48 for farmers; p = 0.002 for the SEP × JH interaction). These findings persisted after adjustment for sociodemographic, behavioral, and biological factors. Results for other SEP measures were in the same direction, but did not reach statistical significance. Repetitive high-effort coping with adversity (John Henryism) was independently associated with increased risk for AMI in Finnish men, underscoring the potential relevance of the John Henryism hypothesis to CVD outcomes other than hypertension and to populations other than African Americans.

Myocardial infarction in relation to mercury and fatty acids from fish: a risk-benefit analysis based on pooled Finnish and Swedish data in men

BACKGROUND

Exposure to methylmercury from fish has been associated with increased risk of myocardial infarction (MI) in some studies. At the same time, marine n-3 (omega-3) PUFAs are an inherent constituent of fish and are regarded as beneficial. To our knowledge, no risk-benefit model on the basis of data on methylmercury, PUFA, and MI risk has yet been presented.

OBJECTIVE

The objective of this study was to describe how exposure to both marine n-3 PUFAs and methylmercury relates to MI risk by using data from Finland and Sweden.

DESIGN

We used matched case-control sets from Sweden and Finland that were nested in population-based, prospective cohort studies. We included 361 men with MI from Sweden and 211 men with MI from Finland. MI risk was estimated in a logistic regression model with the amount of mercury in hair (hair-Hg) and concentrations of n-3 PUFAs (EPA and DHA) in serum (S-PUFA) as independent variables.

RESULTS

The median hair-Hg was 0.57 μg/g in Swedish and 1.32 μg/g in Finnish control subjects, whereas the percentage of S-PUFA was 4.21% and 3.83%, respectively. In combined analysis, hair-Hg was associated with higher (P = 0.005) and S-PUFA with lower (P = 0.011) MI risk. Our model indicated that even a small change in fish consumption (ie, by increasing S-PUFA by 1%) would prevent 7% of MIs, despite a small increase in mercury exposure. However, at a high hair-Hg, the modeled beneficial effect of PUFA on MI risk was counteracted by methylmercury.

CONCLUSIONS

Exposure to methylmercury was associated with increased risk of MI, and higher S-PUFA concentrations were associated with decreased risk of MI. Thus, MI risk may be reduced by the consumption of fish high in PUFAs and low in methylmercury.

T-wave inversion on electrocardiogram is related to the risk of acute coronary syndrome in the general population

BACKGROUND

T-wave inversion (TWI) is a frequently encountered electrocardiographic (ECG) finding during routine medical examination of asymptomatic individuals, and of patients with various clinical conditions. However, the role of isolated TWI in the prediction of acute coronary syndrome (ACS) in the community has not been extensively studied. We investigated the relationship between TWI in routine ECG and the risk for ACS in the general population.

METHODS

This study is based on a random sample of 1997 men aged 42-60 years in Eastern Finland. Electrocardiograms recorded at rest were classified using the Minnesota codes. The association between isolated TWI and ACS was determined using a multivariable adjusted Cox proportional hazard model.

RESULTS

Negative T-waves were present in 3.6% of the participants. During an average follow-up of 20 years, a total of 493 ACS events were registered. After adjusting for age, TWI was associated with a 3.10-fold (95% confidence interval (CI) 2.21-4.32) risk for ACS. After additional adjustment for previously known coronary risk factors, TWI remained statistically significant in predicting ACS (relative risk 2.23; 95% CI 1.57-3.15). Negative T-waves was one of the strongest risk markers for ACS compared with other ECG-based variables such as left ventricular hypertrophy, previous Q-wave and prolonged QRS duration.

CONCLUSION

TWI has a strong and independent predictive value for ACS in the general population.

The metabolic syndrome predicts incident congestive heart failure: a 20-year follow-up study of elderly Finns

OBJECTIVE

We investigated whether the metabolic syndrome (MetS) and its components defined by four different criteria including subjects with prevalent diabetes in their definitions were associated with congestive heart failure (CHF) independent of interim myocardial infarction (MI) and prevalent diabetes during a 20-year follow-up in an elderly population-based study.

METHODS AND RESULTS

The MetS was defined according to the World Health Organization (WHO), the National Cholesterol Education Program (NCEP), the International Diabetes Federation (IDF), and the American Heart Association and the National Heart, Lung, and Blood Institute (AHA) criteria. The association of the MetS with incident CHF (303 cases) was investigated with Cox regression analyses in a 20-year follow-up study of 1032 Finns, aged 65-74 years at baseline. Among all subjects the MetS by all four criteria was significantly associated with a 1.45-1.74-fold risk for incident CHF after the adjustment for confounding factors. When subjects with interim MI during the follow-up and with prevalent diabetes were excluded, the MetS was significantly associated with a 1.37-1.87-fold risk for incident CHF after the adjustment for confounding factors. Of the single components of the MetS, the following were associated with incident CHF: impaired fasting glucose (IFG) [fasting plasma glucose (FPG)> or = 6.1 mmol/l, Hazards ratio (HR) 1.46 or FPG > or = 5.6 mmol/l, HR 1.62)]; raised blood pressure (BP) [(BP > or = 140/90 mmHg or antihypertensive medications, HR 1.89); central obesity (waist circumference > or = 94 cm in men or > or = 80 cm in women, HR 1.49); (waist circumference > or = 102 cm in men or > or = 88 cm in women, HR 1.48); obesity (body mass index > or = 30 kg/m(2), HR 1.79); and low high-density lipoprotein cholesterol (<1.03 mmol/l in men or <1.29 mmol/l in women, HR 1.55).

CONCLUSIONS

The MetS defined by four different criteria predicted CHF independent of interim MI and prevalent diabetes in elderly Finns, but not above and beyond the risk associated with one component of the MetS, hypertension.

High differentiation among eight villages in a secluded area of Sardinia revealed by genome-wide high density SNPs analysis

To better design association studies for complex traits in isolated populations it's important to understand how history and isolation moulded the genetic features of different communities. Population isolates should not “a priori” be considered homogeneous, even if the communities are not distant and part of a small region. We studied a particular area of Sardinia called Ogliastra, characterized by the presence of several distinct villages that display different history, immigration events and population size. Cultural and geographic isolation characterized the history of these communities. We determined LD parameters in 8 villages and defined population structure through high density SNPs (about 360 K) on 360 unrelated people (45 selected samples from each village). These isolates showed differences in LD values and LD map length. Five of these villages show high LD values probably due to their reduced population size and extreme isolation. High genetic differentiation among villages was detected. Moreover population structure analysis revealed a high correlation between genetic and geographic distances. Our study indicates that history, geography and biodemography have influenced the genetic features of Ogliastra communities producing differences in LD and population structure. All these data demonstrate that we can consider each village an isolate with specific characteristics. We suggest that, in order to optimize the study design of complex traits, a thorough characterization of genetic features is useful to identify the presence of sub-populations and stratification within genetic isolates.

The Metabolic Syndrome Predicts Incident Stroke

Background and Purpose— Limited information is available on the role of the metabolic syndrome (MetS) to predict stroke. We investigated the relationship of the MetS and its single components, defined by 6 different criteria, with stroke in a prospective population-based study.

Methods— The MetS was defined according to the World Health Organization, the European Group for the Study of Insulin Resistance, the National Cholesterol Education Program (NCEP), the American College of Endocrinology, the International Diabetes Federation, and the American Heart Association (updated NCEP) criteria. We investigated the relationship of the MetS with stroke using Cox regression analyses in 991 Finnish subjects without diabetes, aged 65 to 74 years at baseline, and followed-up for 14 years.

Results— The MetS defined by the World Health Organization, European Group for the Study of Insulin Resistance, NCEP, International Diabetes Federation, and updated NCEP criteria was significantly associated with incident stroke (fatal and nonfatal) when adjusted for confounding variables (HR, 1.52 to 1.72). After exclusion of subjects with myocardial infarction, these 5 definitions still predicted stroke (HR, 1.49 to 1.80). Of the single components of the MetS, the following predicted stroke in multivariable models when subjects with myocardial infarction were excluded: impaired glucose tolerance (2-hour glucose in an oral glucose tolerance test, 7.8 to 11.0 mmol/L) by the World Health Organization and American College of Endocrinology criteria (HR, 1.66); insulin resistance (HR, 1.60) by the European Group for the Study of Insulin Resistance criteria; and central obesity (HR, 1.52) by the NCEP criteria.

Conclusions— The MetS defined by the 6 criteria except for the American College of Endocrinology definition predicts stroke in elderly subjects. However, impaired glucose tolerance alone is as strong a predictor of stroke as is the MetS defined by the World Health Organization, NCEP and updated NCEP criteria.

Usefulness of chronotropic incompetence in response to exercise as a predictor of myocardial infarction in middle-aged men without cardiovascular disease

An attenuated heart rate (HR) response to exercise, or chronotropic incompetence, has been shown to predict adverse cardiac events in subjects without known cardiovascular disease (CVD). The aim of the present study was to investigate whether chronotropic incompetence independently predicts acute myocardial infarction (AMI) in middle-aged men. In addition to previously established chronotropic incompetence variables, we focused on a new chronotropic incompetence variable, the HR increase from 40% to 100% of maximal work capacity (HR40-100), as a predictor of AMI. The subjects were a representative sample of 1,176 middle-aged men who did not have CVD and did not use HR-lowering medication at baseline. The association of chronotropic incompetence variables with the risk of AMI was examined by Cox regression models including numerous known risk factors for AMI. During an average follow-up of 11.0 years, there were 106 AMIs (9.0%). In Cox multivariable model, the risk of AMI increased by 33% for each SD decrement of 13 beats/min in HR40-100 (95% confidence interval [CI] 9 to 64). When considered concurrently, HR40-100 was the only chronotropic incompetence variable that improved the predictive value of the model containing other risk factors for AMI. Men with a low HR40-100 (<46 beats/min) and a heightened increase in systolic blood pressure (SBP) (>67 mm Hg) were at particularly high risk, with a 3.1-times higher incidence of AMI than those with a normal HR40-100 and SBP increase (95% CI 1.7 to 5.7). In conclusion, a low HR40-100 predicted AMI in men without previous CVD independent of other exercise test or clinical variables.

Metabolic syndrome and incident end-stage peripheral vascular disease: a 14-year follow-up study in elderly Finns

OBJECTIVE

We investigated the relationship of the metabolic syndrome and its single components, defined by four different criteria, with peripheral vascular disease (PVD) in a prospective population-based study.

RESEARCH DESIGN AND METHODS

The metabolic syndrome was defined according to the World Health Organization (WHO), the National Cholesterol Education Program (NCEP), the International Diabetes Federation (IDF), and the American Heart Association (updated NCEP) criteria. We investigated the relationship of the metabolic syndrome defined by the aforementioned four criteria with PVD (revacularization and amputation) by Cox regression analyses in a Finnish population of 1,212 subjects, aged 65-74 years, with and without diabetes during a 14-year follow-up.

RESULTS

The metabolic syndrome defined by the WHO, NCEP, and updated NCEP criteria was associated with a statistically significant risk for incident PVD (n = 57) with adjustment for all confounding variables except for prevalent diabetes (hazard ratios [HRs] from 1.91 to 2.62). After adjustment for prevalent diabetes or after the exclusion of subjects with prevalent diabetes, there was no association between the metabolic syndrome by any criteria and incident PVD. Of the single components of the metabolic syndrome, elevated fasting glucose by the WHO and NCEP criteria (HR 2.35) and microalbuminuria by the WHO definition (2.56) predicted PVD in multivariable models (prevalent diabetes included).

CONCLUSIONS

The metabolic syndrome defined by the WHO, NCEP, and updated NCEP criteria predicted incident end-stage PVD in elderly Finns but only when not adjusted for diabetes status. Two of the single components of the metabolic syndrome, elevated fasting plasma glucose and microalbuminuria, predicted PVD. We conclude that the metabolic syndrome predicts PVD but not above and beyond the risk associated with diabetes and microalbuminuria.

Functional COMT Val158Met polymorphism, risk of acute coronary events and serum homocysteine: the Kuopio ischaemic heart disease risk factor study

Background

The role of circulating levels of total homocysteine tHcy in the development of coronary heart disease (CHD) is still under debate. One reason for conflicting results between previous studies on homocysteine and heart diseases could be consequence of different interactions between homocysteine and genes in different study populations. Many genetic factors play a role in folate-homocysteine metabolism, like functional polymorphism (Val108Met) in the Catechol-O-methyltransferase (COMT) gene.

Methodology and Findings

Our aim was to examine the role of COMT Val158Met polymorphism and interaction of this polymorphism with serum tHcy and folate concentration on the risk of acute coronary and events in middle-aged men from eastern Finland. A population-based prospective cohort of 792 men aged 46–64 years was examined as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up of 9.3 years, there were 69 acute coronary events in men with no previous history of CHD. When comparing the COMT low activity genotype with the others, we found an age and examination year adjusted hazard rate ratio (HRR) of 1.73 (95% confidence interval (CI), 1.07–2.79), and an age, examination year, serum LDL and HDL cholesterol, and triglyceride concentration, systolic blood pressure and smoking adjusted HRR of 1.77 (95% CI, 1.05–2.77). Although serum tHcy concentration was not statistically significantly associated with acute coronary events (HRR for the highest third versus others 1.52, 95% CI, 0.93–2.49), subjects with both high serum tHcy and the COMT low activity genotype had an additionally increased adjusted risk of HRR 2.94 (95% CI 1.50–5.76) as compared with other men.

Conclusions

This prospective cohort study suggests that the functional COMT Val158Met polymorphism is associated with increased risk of acute coronary events and it may interact with high serum tHcy levels.

Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events

Background

The role of coffee intake as a risk factor for coronary heart disease (CHD) has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT) gene.

Methodology/Principal Findings

In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984–89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval) comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2–8.4). Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend).

Conclusions/Significance

Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.

Regional differences among the Finns: A Y-chromosomal perspective

Twenty-two Y-chromosomal markers, consisting of fourteen biallelic markers (YAP/DYS287, M170, M253, P37, M223, 12f2, M9, P43, Tat, 92R7, P36, SRY-1532, M17, P25) and eight STRs (DYS19, DYS385a/b, DYS388, DYS389I/II, DYS390, DYS391, DYS392, DYS393), were analyzed in 536 unrelated Finnish males from eastern and western subpopulations of Finland. The aim of the study was to analyze regional differences in genetic variation within the country, and to analyze the population history of the Finns. Our results gave further support to the existence of a sharp genetic border between eastern and western Finns so far observed exclusively in Y-chromosomal variation. Both biallelic haplogroup and STR haplotype networks showed bifurcated structures, and similar clustering was evident in haplogroup and haplotype frequencies and genetic distances. These results suggest that the western and eastern parts of the country have been subject to partly different population histories, which is also supported by earlier archaeological, historical and genetic data. It seems probable that early migrations from Finno-Ugric sources affected the whole country, whereas subsequent migrations from Scandinavia had an impact mainly on the western parts of the country. The contacts between Finland and neighboring Finno-Ugric, Scandinavian and Baltic regions are evident. However, there is no support for recent migrations from Siberia and Central Europe. Our results emphasize the importance of incorporating Y-chromosomal data to reveal the population substructure which is often left undetected in mitochondrial DNA variation. Early assumptions of the homogeneity of the isolated Finnish population have now proven to be false, which may also have implications for future association studies.

Social disadvantages in childhood and risk of all-cause death and cardiovascular disease in later life: a comparison of historical and retrospective childhood information

BACKGROUND

Childhood socioeconomic circumstances have been shown to contribute to adult mortality. The purpose of this study was to compare the association between objective historical records and recalled questionnaire-based information on childhood socioeconomic position (SEP) with regard to cardiovascular and all-cause mortality.

METHODS

We examined the association between a socially disadvantaged childhood and all-cause mortality, cardiovascular disease (CVD) mortality, coronary heart disease (CHD) mortality, and acute coronary events among male participants in the Kuopio Ischemic Heart Disease (KIHD) Risk Factor Study, a population-based cohort study in eastern Finland with follow-up until 2002. The historical data on childhood factors were collected from school health records (n = 698), mainly from the 1930s to the 1950s. Recall data on socioeconomic conditions in childhood were obtained from the baseline examinations of the KIHD cohort (n = 2,682) in 1984-89.

RESULTS

According to original school health records the men who were socially disadvantaged in childhood had a 1.41-fold (95% confidence interval 1.01-1.97) age-adjusted and examination-year-adjusted risk of all-cause death, a 1.32-fold (0.83-2.11) risk of CVD death, a 1.48-fold (0.85-2.57) risk of CHD death, and a 1.50-fold (1.02-2.20) risk of acute coronary events. After adjustment for biological and behavioural risk factors and for the SEP in adulthood the association was attenuated in all-cause death but did not change in CVD death, CHD death, and acute coronary events. On the contrary, the questionnaire-based recalled childhood data on childhood SEP showed no associations with mortality or acute coronary events.

CONCLUSIONS

With regard to adult mortality, the use of historical records concerning hygiene and living conditions collected in childhood may either provide more accurate measures of early-life socioeconomic conditions or capture more relevant aspects of childhood socioeconomic disadvantage than retrospective recall data.

High dietary methionine intake increases the risk of acute coronary events in middle-aged men

BACKGROUND AND AIM

Homocysteine, a methionine metabolite, is suggested to be a risk factor for cardiovascular diseases (CVD). To date, the effects of dietary intake of methionine, the key amino acid in homocysteine metabolism, on CVD have not been studied. Our aim was to examine the effects of dietary methionine intake on the risk of acute coronary events.

METHODS AND RESULTS

We examined the effects of dietary methionine intake, assessed with 4-d food record, on acute coronary events in a prospective cohort study consisting of 1981 coronary disease free men from eastern Finland, aged 42-60 years at baseline in 1984-89, in the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. During an average follow-up time of 14.0 years, 292 subjects experienced an acute coronary event. In a Cox proportional hazards model adjusting for age, examination years, BMI, urinary nicotine metabolites and protein intake (excluding methionine) the relative risks of acute coronary event in the three highest quarters of dietary methionine intake were 1.31 (95% CI: 0.92, 1.86), 1.31 (95% CI: 0.88, 1.96) and 2.08 (95% CI: 1.31, 3.29) as compared with the lowest quarter. Further adjustments did not change the results. However, opposite association was observed with total protein intake, which tended to decrease the risk.

CONCLUSIONS

The main finding of this study is that long-term, moderately high dietary methionine intake may increase the risk of acute coronary events in middle-aged Finnish men free of prior CHD. More prospective research is needed to confirm the role of dietary methionine in the development of CVD, and whether its effects are independent of homocysteine.

Subpopulation difference scanning: a strategy for exclusion mapping of susceptibility genes

BACKGROUND

Association mapping is a common strategy for finding disease-related genes in complex disorders. Different association study designs exist, such as case-control studies or admixture mapping.

METHODS

We propose a strategy, subpopulation difference scanning (SDS), to exclude large fractions of the genome as locations of genes for complex disorders. This strategy is applicable to genes explaining disease incidence differences within founder populations, for example, in cardiovascular diseases in Finland.

RESULTS

The strategy consists of genotyping a set of markers from unrelated individuals sampled from subpopulations with differing disease incidence but otherwise as similar as possible. When comparing allele or haplotype frequencies between the subpopulations, the genomic areas with little difference can be excluded as possible locations for genes causing the difference in incidence, and other areas therefore targeted with case-control studies. As tests of this strategy, we use real and simulated data to show that under realistic assumptions of population history and disease risk parameters, the strategy saves efforts of sampling and genotyping and most efficiently detects genes of low risk--that is, those most difficult to find with other strategies.

CONCLUSION

In contrast to admixture mapping that uses the mixing of two different populations, the SDS strategy takes advantage of drift within highly related subpopulations.

C-reactive protein in the prediction of cardiovascular and overall mortality in middle-aged men: a population-based cohort study

AIMS

Cut-offs for C-reactive protein concentrations have been recommended for risk stratification, but little is known about how these cut-offs predict cardiovascular risk in population-based cohorts. We therefore assessed the association of C-reactive protein levels with cardiovascular mortality in a population-based cohort of 2321 middle-aged men stratified by the presence of cardiovascular disease (CVD) at baseline.

METHODS AND RESULTS

C-reactive protein concentrations were categorized according to current recommendations (1 and 3 mg/L). During the 15 year follow-up, 77 men without CVD and 121 men with CVD at baseline died of CVD. In men without CVD at baseline (n=1476), age-adjusted cardiovascular mortality was 4.1-fold higher (95% CI 2.1-8.2) for C-reactive protein levels between 3.0 and 9.9 mg/L at baseline than for C-reactive protein levels <1.0 mg/L. In men with CVD at baseline (n=845), the corresponding age-adjusted cardiovascular mortality was 3.3-fold higher (95% CI 2.0-5.3). Adjustment for conventional CVD risk factors attenuated the risk somewhat. Further adjustment for dietary and lifestyle factors and factors related to insulin resistance did not affect the association. Classification of C-reactive protein by tertiles gave qualitatively similar results, but identified twice as many men at high risk. C-reactive protein levels also predicted overall mortality.

CONCLUSION

Currently, recommended cut-offs for C-reactive protein levels identify men at risk for cardiovascular and overall death independently of conventional and other risk factors in a population-based sample of middle-aged men with and without CVD at baseline. Lower cut-offs may better identify men at high risk for cardiovascular death, but improvement of current recommendations will require standardization of C-reactive protein assays.

Prevalence of diabetes and impaired glucose regulation in 45- to 64-year-old individuals in three areas of Finland

AIMS

To determine the prevalence of diabetes mellitus (DM), impaired glucose tolerance (IGT) and impaired fasting glycaemia (IFG) and possible regional differences in Finnish adults aged between 45 and 64 years.

METHODS

A population sample of 2642 subjects aged between 45 and 64 years living in three geographical areas in Finland was invited to an oral glucose tolerance test.

RESULTS

The glucose tolerance status of 2087 subjects (79.0%) was determined. The age-standardized prevalence of DM in men and women was 10.2% and 7.4%, respectively (P = 0.020 for difference between sexes), and that of IGT 10.5% in men and 9.2% in women. IFG in men was more than twice as common as in women (13.5% vs. 5.0%, respectively, P < 0.001). Abnormal glucose tolerance was most common in southern compared with southwestern and eastern Finland. Of all diabetic subjects, 44% were previously undiagnosed.

CONCLUSIONS

The age-standardized prevalence of DM in 45- to 64-year-old Finns was within the range defined in previous studies on Europid populations. DM and IFG were more common in men than in women. Regional differences in the prevalence of abnormal glucose regulation suggest differences in lifestyle within an ethnically homogenous population.

Systolic Blood Pressure During Recovery From Exercise and the Risk of Acute Myocardial Infarction in Middle-Aged Men

We prospectively assessed the association of systolic blood pressure (SBP) after exercise with the risk of an acute myocardial infarction. Limited information exists currently on the role of SBP during recovery period with the risk of acute myocardial infarction. SBP was measured every 2 minutes during and after a progressive cycle ergometer exercise test in a representative sample of 2336 men (aged 42 to 61 years). During an average follow-up period of 13.1 years, 358 acute myocardial infarctions occurred. An incremental rise of 10 mm Hg per minute in SBP at 2 minutes after exercise (relative risk, 1.07-fold; 95% confidence interval [CI], 1.03 to 1.12; P=0.001) was associated with the risk of acute myocardial infarction after adjustment for age, alcohol consumption, smoking, serum lipids, diabetes mellitus, body mass index, resting SBP, regular use of antihypertensive medications, physical fitness, heart rate, and ischemic ECG findings during exercise. Men with elevated SBP of >195 mm Hg after exercise had a 1.69-fold (95% CI, 1.24 to 2.30; P=0.001) risk for an acute myocardial infarction compared with those with SBP <170 mm Hg after adjustment for age, other risk factors, and resting SBP. SBP after exercise provides an incremental predictive value for acute myocardial infarction beyond that of resting SBP. This emphasizes the importance of SBP measurements after the exercise test because it provides additional valuable prognostic measure with regard to acute myocardial infarction.

Mercury, fish oils, and risk of acute coronary events and cardiovascular disease, coronary heart disease, and all-cause mortality in men in eastern Finland

OBJECTIVE

Mercury has been suggested to have negative effects on cardiovascular health. We investigated the effects of high mercury content in hair on the risk of acute coronary events and cardiovascular and all-cause mortality in men from eastern Finland.

METHODS AND RESULTS

The population-based prospective Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) cohort of 1871 Finnish men aged 42 to 60 years and free of previous coronary heart disease (CHD) or stroke at baseline was used. During an average follow-up time of 13.9 years, 282 acute coronary events and 132 cardiovascular disease (CVD), 91 CHD, and 525 all-cause deaths occurred. Men in the highest third of hair mercury content (>2.03 microg/g) had an adjusted 1.60-fold (95% CI, 1.24 to 2.06) risk of acute coronary event, 1.68-fold (95% CI, 1.15 to 2.44) risk of CVD, 1.56-fold (95% CI, 0.99 to 2.46) risk of CHD, and 1.38-fold (95% CI, 1.15 to 1.66) risk of any death compared with men in the lower two thirds. High mercury content in hair also attenuated the protective effects of high-serum docosahexaenoic acid plus docosapentaenoic acid concentration.

CONCLUSIONS

High content of mercury in hair may be a risk factor for acute coronary events and CVD, CHD, and all-cause mortality in middle-aged eastern Finnish men. Mercury may also attenuate the protective effects of fish on cardiovascular health.

Prevalence of the metabolic syndrome and its components: findings from a Finnish general population sample and the Diabetes Prevention Study cohort

OBJECTIVE

To assess the prevalence of the metabolic syndrome (MetS) in two independent Finnish study cohorts.

RESEARCH DESIGN AND METHODS

The prevalence of the MetS by modified World Health Organization criteria was analyzed in different categories of glucose tolerance in a cross-sectional, population-based sample of 2,049 individuals (FINRISK) aged 45-64 years and in 522 participants of the Finnish Diabetes Prevention Study (DPS) with impaired glucose tolerance (IGT).

RESULTS

In the FINRISK cohort, the MetS was present in 38.8% of the men and 22.2% of the women. The prevalence was 14.4 and 10.1% in subjects with normal glucose tolerance, 74.0 and 52.2% in subjects with impaired fasting glucose, 84.8 and 65.4% in subjects with IGT, and 91.5 and 82.7% in subjects with type 2 diabetes in men and women, respectively. Among women, the prevalence of the MetS increased with increasing age. In the DPS cohort, the MetS was present in 78.4% of the men and 72.2% of the women with IGT.

CONCLUSIONS

The MetS was extremely common in middle-aged subjects The high prevalence in men was mostly due to their high waist-to-hip ratio. The prevalence of the MetS increased in both sexes with deterioration in glucose regulation. Approximately 75% of the subjects with IGT had the MetS. Because the syndrome includes the major risk factors for atherosclerotic vascular diseases and is the major antecedent for type 2 diabetes, concerted preventive action should be targeted to control all the features of the MetS.

Coffee drinking is dose-dependently related to the risk of acute coronary events in middle-aged men

Heavy coffee consumption has been associated with increased coronary heart disease (CHD) risk although many studies have not observed any relation. We studied the effect of coffee consumption, assessed with a 4-d food record, on the incidence of nonfatal acute myocardial infarction or coronary death in a cohort of 1971 men who were 42 to 60 y old and free of symptomatic CHD at baseline in 1984-1989. During a mean follow-up of 14 y, 269 participants experienced an acute coronary event. After adjustment for age, smoking, exercise ischemia, diabetes, income, and serum insulin concentration, the rate ratios (95% CIs) in daily nondrinkers and light (375 mL or less), moderate (reference level), and heavy (814 mL or more) drinkers were 0.84 (0.41-1.72), 1.22 (0.90-1.64), 1.00, and 1.43 (1.06-1.94). To address time dependence of the effect, the analysis was repeated for 75 CHD events that occurred during the first 5 y; the respective rate ratios were 0.42 (0.06-3.10), 2.00 (1.16-3.44), 1.00, and 2.07 (1.17-3.65). Further adjustment for serum HDL and LDL cholesterol concentration, diastolic blood pressure, maximal oxygen uptake, and waist-hip ratio slightly increased the rate ratio for heavy coffee intake. Neither the brewing method (boiling vs. filtering) nor the serum LDL cholesterol concentration had any impact on the risk estimates for coffee intake. In conclusion, heavy coffee consumption increases the short-term risk of acute myocardial infarction or coronary death, independent of the brewing method or currently recognized risk factors for CHD.

Serum folate and homocysteine and the incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Several, but not all, prospective studies have shown that low folate intakes, low circulating folate concentrations, or high plasma total homocysteine (tHcy) concentrations are associated with an increased risk of coronary artery disease (CAD).

OBJECTIVE

We examined the relations of both serum folate and serum tHcy concentrations with acute coronary events in middle-aged men from eastern Finland who had no CAD at baseline.

DESIGN

In a population-based prospective cohort study, 1027 men aged 46-64 y were examined in 1991-1993 as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up of 7.7 y (7900 person-years of follow-up), 114 acute coronary events were observed in 61 men who had no previous history of CAD (n = 810).

RESULTS

In a Cox model, compared with men whose serum folate concentrations were in the lowest tertile, those whose concentrations were in the highest tertile had a risk factor-adjusted relative risk of acute coronary events of 0.35 (95% CI: 0.17, 0.73; P = 0.005). Serum tHcy concentrations were not significantly associated with the risk of acute coronary events (for the highest tertile compared with the lowest, adjusted relative risk = 1.03; 95% CI: 0.57, 1.87; P = 0.932).

CONCLUSIONS

The results of this prospective cohort study do not support the hypothesis that a high circulating tHcy concentration is a risk factor for acute coronary events in a male population free of prior heart disease. However, they do suggest that moderate-to-high serum folate concentrations are associated with a greatly reduced incidence of acute coronary events.

The diabetes risk score: a practical tool to predict type 2 diabetes risk

OBJECTIVE

Interventions to prevent type 2 diabetes should be directed toward individuals at increased risk for the disease. To identify such individuals without laboratory tests, we developed the Diabetes Risk Score.

RESEARCH DESIGN AND METHODS

A random population sample of 35- to 64-year-old men and women with no antidiabetic drug treatment at baseline were followed for 10 years. New cases of drug-treated type 2 diabetes were ascertained from the National Drug Registry. Multivariate logistic regression model coefficients were used to assign each variable category a score. The Diabetes Risk Score was composed as the sum of these individual scores. The validity of the score was tested in an independent population survey performed in 1992 with prospective follow-up for 5 years.

RESULTS

Age, BMI, waist circumference, history of antihypertensive drug treatment and high blood glucose, physical activity, and daily consumption of fruits, berries, or vegetables were selected as categorical variables. Complete baseline risk data were found in 4435 subjects with 182 incident cases of diabetes. The Diabetes Risk Score value varied from 0 to 20. To predict drug-treated diabetes, the score value >or=9 had sensitivity of 0.78 and 0.81, specificity of 0.77 and 0.76, and positive predictive value of 0.13 and 0.05 in the 1987 and 1992 cohorts, respectively.

CONCLUSIONS

The Diabetes Risk Score is a simple, fast, inexpensive, noninvasive, and reliable tool to identify individuals at high risk for type 2 diabetes.

Geographical variation in the incidence of acute myocardial infarction in eastern Finland--a Bayesian perspective

BACKGROUND

Large geographical variation in the incidence and mortality of cardiovascular disease (CHD) has been repeatedly reported in Finland with persistent difference between east and west. We undertook this study to estimate the geographical distribution of Acute Myocardial Infarction (AMI) incidence in the high-risk province of North Karelia and in the province of Kuopio.

METHODS

Data on men aged 25-64 years with first event of acute myocardial infarction (AMI) were obtained from the FINMONICA AMI register, which recorded detailed information of AMI events during the period 1983 to 1992. The geographical pattern of AMI incidence was studied in two five-year periods 1983 to 1987 and 1988 to 1992 separately in 10 km x 10 km grid cells employing the Geographical Information System (GIS) and a Bayesian hierarchical approach.

RESULTS

In both periods Bayesian modeling revealed a geographical pattern of AMI incidence and high risk (probability that incidence exceeds the observed mean incidence) in the remote rural areas.

CONCLUSIONS

Detection of high-risk areas in both provinces showed that underlying environmental and/or genetic risk factors of AMI are not evenly distributed within the province but enriched in certain geographical non-administratively defined locations in eastern Finland.

Gender differences in the management and survival of patients with acute myocardial infarction

Coronary heart disease (CHD) and specifically acute myocardial infarction (AMI) are the most common causes of death among both men and women throughout the world. Although CHD mortality rates have been halved in many developed countries in recent decades, some studies have pointed out significant differences regarding time-related tendencies of mortality between the sexes. This paper briefly reviews factors related to post-AMI survival and possible reasons for inequalities in survival benefit between men and women after AMI. Presentation of AMI also exhibits differences with regard to sex, and this has some effect on patient care and on mortality from the disease. CHD morbidity and mortality rates vary with socioeconomic deprivation and social patterning in most industrialized countries. Several studies have indicated that women sustaining AMI have a higher mortality than men. Although AMI affects men in greater numbers, the short-term outcomes for women are worse. Studies suggest that, over the longer term, the mortality risk for women is lower than, or similar to, that for men. It is still a major problem that in-hospital case fatality and morbidity rates in the post-infarction period are higher for women, despite lower rates of administration of thrombolytics and catheterization. Patients admitted to the hospital with an AMI should be offered optimal treatment, irrespective of age or sex.

Arginine intake, blood pressure, and the incidence of acute coronary events in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Evidence suggests that dietary supplementation of L-arginine, the precursor of nitric oxide, may protect arteries against atherosclerosis.

OBJECTIVE

We tested the hypothesis that dietary arginine intake is associated with a decreased risk of acute coronary events in Finnish men aged 42-60 y.

DESIGN

We investigated this association in a prospective cohort study of men who were free of prior coronary artery disease and who were examined in 1984-1989 in the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD). The dietary arginine intake of 1981 men was assessed by a 4-d food intake record during the baseline phase of the KIHD.

RESULTS

Men in the highest quintile of dietary arginine intake (>or= 5691 mg/d) did not have a significantly lower risk of acute coronary events than did men in the 4 lower quintiles (relative risk after adjustment for potential coronary risk factors: 1.28; 95% CI: 0.85, 1.94). The covariates were age; examination years; body mass index; systolic blood pressure; serum total, HDL, and LDL cholesterol; serum triacylglycerols; urinary excretion of nicotine metabolites; maximal oxygen uptake in an exercise test; and alcohol intake. Splitting arginine intake into deciles or analyzing plant- and animal-derived arginine separately did not show any association between dietary arginine intake and the risk of acute coronary events. Arginine intake was also not consistently associated with blood pressure.

CONCLUSION

Dietary arginine intake is not associated with the risk of acute coronary events in middle-aged men in eastern Finland.

Insulin resistance syndrome predicts coronary heart disease events in elderly type 2 diabetic men

OBJECTIVE

To investigate whether cardiovascular risk factors cluster with hyperinsulinemia in elderly type 2 diabetic subjects and, if so, whether this clustering predicts coronary heart disease (CHD) events during a 7-year follow-up.

RESEARCH DESIGN AND METHODS

Clustering of cardiovascular risk factors was analyzed by factor analysis. Cox regression models were used to investigate whether these clusters (factors) predict CHD events (CHD death or nonfatal myocardial infarction) during a 7-year follow-up in 229 type 2 diabetic subjects aged 65-74 years.

RESULTS

There were 70 CHD events (21 in men and 49 in women) during the follow-up period. In diabetic men, components of the insulin resistance syndrome (IRS) loaded on Factor 1 (the insulin resistance factor), which reflected high fasting insulin, obesity (high BMI), central obesity (high waist-to-hip ratio), high total triglycerides, and a short duration of diabetes. Only this IRS factor predicted CHD events in multivariate Cox regression analysis (hazard ratio [HR] 1.71, 95% CI 1.08-2.71, P = 0.022). In diabetic women, components of IRS loaded on two factors, none of which predicted CHD events. In women, only Factor 4, characterized by advanced age, left ventricular hypertrophy on electrocardiogram, high alcohol consumption, high systolic blood pressure, and albuminuria, predicted CHD events in multivariate Cox regression analysis (1.34, 1.03-1.74, P = 0.03).

CONCLUSIONS

IRS is a risk factor for CHD in elderly type 2 diabetic men.

Exercise-induced silent myocardial ischemia and coronary morbidity and mortality in middle-aged men

OBJECTIVES

We investigated the prognostic significance of exercise-induced silent myocardial ischemia in both high and low risk men with no prior coronary heart disease (CHD).

BACKGROUND

Silent ischemia predicts future coronary events in patients with CHD, but there is little evidence of its prognostic significance in subjects free of CHD.

METHODS

We investigated the association of silent ischemia, as defined by ST depression during and after maximal symptom-limited exercise test, with coronary risk in a population-based sample of men with no prior CHD followed for 10 years on average.

RESULTS

Silent ischemia during exercise was associated with a 5.9-fold (95% CI 2.3 to 11.8) CHD mortality in smokers, 3.8-fold (95% CI 1.9 to 7.9) in hypercholesterolemic men and 4.7-fold (95% CI 2.4 to 9.1) in hypertensive men adjusting for other risk factors. The respective relative risks (RRs) of any acute coronary event were 3.0 (95% CI 1.7 to 5.1), 1.9 (95% CI 1.2 to 3.1) and 2.2 (95% CI 1.4 to 3.5). These associations were weaker in men without these risk factors. Furthermore, silent ischemia after exercise was a stronger predictor for the risk of acute coronary events and CHD death in smokers and in hypercholesterolemic and hypertensive men than in men without risk factors.

CONCLUSIONS

Exercise-induced silent myocardial ischemia was a strong predictor of CHD in men with any conventional risk factor, emphasizing the importance of exercise testing to identify asymptomatic high risk men who could benefit from risk reduction and preventive measures.

Relation of socioeconomic position to the case fatality, prognosis and treatment of myocardial infarction events; the FINMONICA MI Register Study

OBJECTIVE

To examine socioeconomic differences in case fatality and prognosis of myocardial infarction (MI) events, and to estimate the contributions of incidence and case fatality to socioeconomic differences in coronary heart disease (CHD) mortality.

DESIGN

A population-based MI register study.

METHODS

The FINMONICA MI Register recorded all MI events among persons aged 35-64 years in three areas of Finland during 1983-1992. A record linkage of the MI Register data with the files of Statistics Finland was performed to obtain information on socioeconomic indicators for each individual registered. First MI events (n=8427) were included in the analyses.

MAIN RESULTS

The adjusted risk ratio of prehospital coronary death was 2.11 (95% CI 1.82, 2.46) among men and 1.68 (1.14, 2.48) among women with low income compared with those with high income. Even among persons hospitalised alive the risk of death during the next 12 months was markedly higher in the low income group than in the high income group. Case fatality explained 51% of the CHD mortality difference between the low and the high income groups among men and 38% among women. Incidence contributed 49% and 62%, respectively.

CONCLUSIONS

Considerable socioeconomic differences were observed in the case fatality of first coronary events both before hospitalisation and among patients hospitalised alive. Case fatality explained a half of the CHD mortality difference between the low and the high income groups among men and more than a third among women.

Low serum lycopene concentration is associated with an excess incidence of acute coronary events and stroke: the Kuopio Ischaemic Heart Disease Risk Factor Study

A number of epidemiological studies have shown an association between beta-carotene and the risk of cardiovascular diseases, whereas only a few studies are available concerning the association of lycopene with the risk of coronary events, and no studies have been undertaken concerning lycopene and stroke. Thus, we tested the hypothesis that low serum levels of lycopene are associated with increased risk of acute coronary events and stroke in middle-aged men previously free of CHD and stroke. The subjects were 725 men aged 46-64 years examined in 1991-3 in the Kuopio Ischaemic Heart Disease Risk Factor Study. Forty-one men had either a fatal or a non-fatal acute coronary event or a stroke by December 1997. In a Cox' proportional hazard's model adjusting for examination years, age, systolic blood pressure and three nutritional factors (serum folate, beta-carotene and plasma vitamin C), men in the lowest quarter of serum lycopene levels (< or =0.07 micromol/l) had a 3.3-fold (95 % CI 1.7, 6.4, risk of acute coronary events or stroke compared with the others. Our study suggests that a low serum level of lycopene is associated with an increased risk of atherosclerotic vascular events in middle-aged men previously free of CHD and stroke.

Short stature and coronary heart disease: a 35-year follow-up of the Finnish cohorts of The Seven Countries Study

OBJECTIVES

To examine whether short stature is associated with an increased risk of coronary heart disease.

DESIGN

Follow-up study.

SETTING

Two geographically defined areas in eastern and western Finland.

SUBJECTS

A total of 1441 men who were free of coronary heart disease at the start of the follow-up.

MAIN OUTCOME MEASURES

Hazard ratios for fatal and non-fatal coronary heart disease

RESULTS

Height was inversely related to fatal coronary heart disease and incident non-fatal coronary heart disease during the follow-up. These relationships persisted after adjusting for other major cardiovascular risk factors. Comparing the high-risk area in eastern Finland with the low-risk area in south-western Finland, no difference in fatal coronary heart disease and cumulative incidence of non-fatal coronary heart disease was seen in tall men. The increase in risk of coronary heart disease death was 19% for a 10 cm decrease in height (OR = 0.81, 95% CI = 0.68-0.95).

CONCLUSIONS

Our results show that short stature is an independent risk factor for coronary heart disease. Differences in stature partly explain the Finnish east-west difference in the incidence of coronary heart disease.

Plasma total homocysteine concentration and the risk of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study

OBJECTIVES

Results from prospective studies concerning the association between plasma total homocysteine (tHcy) concentration and coronary heart disease (CHD) are conflicting. The purpose of this study was to test the hypothesis that plasma tHcy is associated with an increased risk of acute coronary events in middle-aged men.

DESIGN AND SUBJECTS

We investigated this association in a prospective nested case-control study among Eastern Finnish men aged 42-60 years. Plasma tHcy measurements were carried out for 163 men who had an acute coronary event during an average 8 years and 11 months follow-up of the whole cohort and for 163 control subjects. Both the cases and the controls were from a cohort of 2005 men who had no clinical CHD at the Kuopio Ischaemic Heart Disease (KIHD) baseline.

RESULTS

Men in the highest plasma tHcy concentration quarter had no increase in the risk of coronary events compared with men with lower tHcy concentrations (odds ratio = 0.88, 95% confidence interval 0.44-1.76). Average follow-up time before the first coronary event was 4.9 years (SD 3.2) in men in the highest plasma tHcy quarter and 5.5 years (SD 3.1) in men in the three lowest quarters (P = 0.368).

CONCLUSION

We conclude that plasma tHcy is not associated with an increased risk of coronary events in the middle-aged male population in eastern Finland.

Risk of acute coronary events according to serum concentrations of enterolactone: a prospective population-based case-control study

BACKGROUND

The lignan enterolactone, produced by the intestinal microflora from dietary precursors, has been implicated in protection against cancer. We investigated the association of serum enterolactone concentration with the risk of acute coronary events in a prospective nested case-control study in middle-aged men from eastern Finland.

METHODS

Enterolactone was measured by time-resolved fluoroimmunoassay in serum from 167 men who had an average 7.7 years of follow-up to an acute coronary event and from 167 control men. Both cases and controls were from a cohort of 2005 men who had no clinical coronary heart disease (CHD) at baseline. The controls were matched for age, examination year, and residence. Acute coronary events were registered prospectively.

FINDINGS

The mean baseline serum enterolactone concentration was lower among the cases than the controls (18.2 [SD 21.1] vs 23.5 [18.2] nmol/L, p=0.001). The men in the highest quarter of the enterolactone distribution (>30.1 nmol/L) had a 58.8% (95% CI 24.1-77.6, p=0.005) lower risk of acute coronary events than men in the lowest quarter. After adjustment for the nine most strongly predictive risk factors, men in the highest enterolactone quarter had a 65.3% (11.9-86.3, p=0.03) lower risk than men in the lowest quarter.

INTERPRETATION

Healthy men with high serum concentrations of enterolactone had a lower risk of acute coronary events than men with lower concentrations. These findings support the hypothesis that plant-dominated fibre-rich food lowers the risk of CHD.

LDL size and risk of coronary heart disease in elderly men and women

A predominance of small, dense, low density lipoprotein (LDL) particles has consistently been associated with coronary heart disease (CHD) in young and middle-aged subjects in cross-sectional studies. Recently, 3 prospective, case-control studies showed that decreased LDL size is a predictor of CHD in middle-aged subjects. However, it is not known whether decreased LDL size is mainly associated with premature CHD or whether it continues to play a role in CHD risk at older ages also. We performed a prospective, nested case-control study in 86 subjects (58 nondiabetic and 28 type 2 diabetic) aged 65 to 74 years who were free of myocardial infarction at baseline and who then had a myocardial infarction or CHD death during a 3.5-year follow-up (cases) and in 172 controls matched for sex and diabetes status but who remained free of CHD during follow-up. LDL particle size determined by gradient gel electrophoresis (268.2+/-0.9 versus 268.5+/-0.7 A, P=0.782) and the proportion of subjects with LDL subclass phenotype B (20.9 versus 21. 5, P=0.914) were similar among cases and controls. Furthermore, diastolic blood pressure, total cholesterol, high density lipoprotein cholesterol, triglycerides, apolipoprotein A(1), fasting glucose, fasting insulin, waist-to-hip ratio, and body mass index were not associated with CHD risk. However, smoking and increased systolic blood pressure, apolipoprotein B levels, and the total cholesterol-high density lipoprotein cholesterol ratio were significant predictors of CHD events both in univariate and multivariate analyses. Our findings indicate that LDL size is not a predictor of CHD events in elderly white subjects after controlling for diabetes status.

Insulin resistance syndrome predicts coronary heart disease events in elderly nondiabetic men

BACKGROUND

The role of a cluster of risk factors characteristic for the insulin resistance syndrome as a predictor for coronary heart disease (CHD) has not been studied previously.

METHODS AND RESULTS

Clustering of cardiovascular risk factors was analyzed by factor analysis to investigate whether these clusters (factors) predict CHD events (CHD death or nonfatal myocardial infarction) in a nondiabetic population of 1069 subjects 65 to 74 years old from eastern Finland followed up for 7 years. There were 151 CHD events (92 for men, 59 for women) during the follow-up period. In men, factor 1 (the insulin resistance factor, which reflected primarily body mass index, waist-to-hip ratio, triglycerides, fasting plasma glucose, and insulin) (hazards ratio [HR] with 95% CI, 1.33, CI 1.08, 1.65, P=0.008), factor 2 (alcohol consumption, high HDL cholesterol, low triglycerides) (HR 0.78, CI 0.63, 0.96, P=0.020), factor 3 (age, systolic blood pressure, urinary albumin/creatinine ratio, left ventricular hypertrophy) (HR 1.52, CI 1.26, 1.83, P<0.001), and factor 4 (high total cholesterol and triglycerides) (HR 1.42, CI 1. 15, 1.77, P=0.002) predicted CHD events in multivariate Cox regression analysis. In women, the insulin resistance factor did not predict CHD events (HR 1.06, CI 0.82, 1.36), but factor 2 (previous stroke, low HDL cholesterol and high triglycerides) (HR 1.34, CI 1. 06, 1.69, P=0.014) and factor 3 (age, systolic blood pressure, urinary albumin/creatinine ratio, left ventricular hypertrophy) (HR 1.44, CI 1.15, 1.82, P=0.002) predicted CHD events.

CONCLUSIONS

Our study supports the notion that the insulin resistance syndrome is a risk factor for CHD in elderly men.

Alarmingly high occurrence and case fatality of acute coronary heart disease events in Estonia: results from the Tallinn AMI register 1991-94

OBJECTIVE

The purpose of this study was to produce stable estimates for the incidence, attack and mortality rates and case fatality of acute myocardial infarction (AMI) in Tallinn, the capital of Estonia.

RESEARCH DESIGN AND METHODS

The Tallinn AMI register covers the population aged 25-64 years and official residents of Tallinn. The register follows the WHO MONICA project protocols in the data collection and diagnostic evaluation of the suspected AMI events and CHD death.

RESULTS

Age-standardized annual incidence, attack rate and mortality in men aged 35-64 years were high, varying from (per 100000 per year) 352, 499 and 208, respectively, in 1991 to 438, 628 and 317, respectively, in 1993. In addition, in women, annual incidence, attack rate and mortality were high, varying from (per 100000 per year) 82, 100 and 31, respectively, in 1991 to 110 and 142 in 1993 for the incidence and attack rate, and to 61 in 1992 for mortality. The percentage of out-of-hospital coronary death (sudden death) increased in men from 33 to 52% and in women from 24 to 42% during 1991-94, and the 28-day case fatality increased in men from 42 to 58%, and in women from 32 to 50%. In Tallinn, women with AMI were treated as actively as men with invasive treatment (thrombolysis, angioplasty, bypass surgery) during the acute phase of MI.

CONCLUSIONS

The incidence, attack rate and mortality of AMI were high in both men and women in Tallinn. The high 28-day case fatality observed was primarily due to the high proportion of out-of-hospital deaths.

Computer-assisted electrocardiography in structured diagnosis of acute myocardial infarction

The purpose of this study was to investigate the applicability of computerized electrocardiogram interpretation in classifying patients with suspected acute myocardial infarction. Computerized acquisition and analysis of the 12-lead electrocardiogram can increase the consistency and reduce the workload of patient classification. The serial electrocardiograms of 311 consecutive patients with suspected myocardial infarction were studied and a new computerized myocardial infarction (CMI) electrocardiographic classification was developed and compared with one commercially available and two manual codes. Statistically, there was almost no correlation between the four ECG codes. Compared with the WHO enzymatic criteria, the sensitivity of the CMI code toward detecting definite and possible infarction was 69.2% and 29.8% with a specificity of 62.1% and 79.7%, respectively. In subjects without previous infarction (n = 214) the sensitivity of the CMI code for definite enzymatic infarction was 71.9% and specificity 77.6%. Substituting the CMI for the Minnesota code had no effect on patient classification by the WHO MONICA criteria in 78% of patients with first infarction. Judged by cardiac macromolecular leakage, all electrocardiographic classifications of possible infarction were poorly correlated with myocardial tissue injury. We have developed a new computerized coding system to detect electrocardiographic myocardial infarction. The structure of the code allows interactive redefinition of criteria to meet user-defined needs. However, because of the weak relationship between electrocardiographic and biochemical criteria of myocardial injury, the role of ECG in the diagnostic classification of acute ischemic syndromes should be re-evaluated.

The validity of the routine mortality statistics on coronary heart disease in Finland: comparison with the FINMONICA MI register data for the years 1983-1992. Finnish multinational MONItoring of trends and determinants in CArdiovascular disease

We compared the diagnoses obtained from the routine mortality statistics with the standardized World Health Organization (WHO) MONICA (multinational MONItoring of trends and determinants in CArdiovascular disease) classification in suspect coronary heart disease (CHD) deaths registered in the FINMONICA myocardial infarction (MI) register during 1983-1992. All CHD deaths from routine mortality statistics (International Classification of Diseases codes 410-414) were registered in the MI register. Of the CHD deaths in routine mortality statistics 1.7% in men and 4.8% in women did not fulfill the MONICA criteria for CHD death (P<0.001 for the difference between the sexes). In men 4.7% and in women 7.3% (P=0.004) of the deaths registered in the MI Register and classified as CHD deaths by MONICA criteria had another underlying cause of death than CHD in routine mortality statistics; this proportion increased over time in both sexes (P=0.002 in men and P=0.77 in women). The CHD mortality trends obtained separately from the routine mortality statistics and from the FINMONICA MI Register were very similar. In conclusion, the high CHD mortality in Finland reported by the routine mortality statistics is real. It is possible that some CHD deaths have escaped registration, but the decline seen in the CHD mortality is also real.

Trends in the treatment of patients with myocardial infarction and coronary revascularization procedures in Finland during 1986-92: the FINMONICA Myocardial Infarction Register Study

OBJECTIVES

To investigate changes in the medical treatment of patients with myocardial infarction and the trends in revascularization procedures in Finland.

DESIGN

A population-based myocardial infarction (MI) register study.

SETTING

Populations, aged 25-64 years, of the three geographical areas of Finland, provinces of North Karelia and Kuopio in eastern Finland and the Turku-Loimaa area in south-western Finland.

MAIN OUTCOME MEASURES

Medical treatment administered prior to the coronary event, during the hospitalization and at discharge from hospital to all patients hospitalized due to suspected myocardial infarction and all CAD deaths occurring during three separate 4-month periods in 1986, 1989 and 1992. Data on coronary bypass surgery and percutaneous coronary angioplasty in the study areas for 1986-92.

RESULTS

The most marked change in the medical treatment of hospitalized myocardial infarction patients was the significant increase in the use of thrombolytic treatment (5% of patients in 1986 and 24% in 1992, P < 0.001 for trend). The use of antiplatelet agents increased from 1986 to 1992 prior to the coronary event, during the hospitalization and at discharge. The use of beta-blockers and intravenous nitrates increased and the use of calcium-channel blockers declined significantly in hospitalized patients during the study period. Hospitalized male myocardial infarction patients were treated more often with beta-blockers, nitrates, antiplatelet agents and thrombolytic agents than female patients, suggesting less intensive medical treatment in women.

CONCLUSION

The results of the large clinical trials regarding the medical treatment of myocardial infarction patients were adopted in the clinical practice rapidly and the treatment of myocardial infarction patients and the number of revascularization procedures changed markedly from 1986 to 1992 in Finland. These changes may in part explain the favourable changes in mortality from CAD in Finland.

Role of known risk factors in explaining the difference in the risk of coronary heart disease between eastern and southwestern Finland

We analysed to what extent cardiovascular risk factors may explain the observed difference in the risk of coronary heart disease (CHD) between two areas with markedly different CHD incidence. The study included 7049 men aged 25-64 years who had participated in a baseline survey in 1982 or in 1987 in the Kuopio and North Karelia provinces of eastern Finland and in the Turku-Loimaa region of southwestern Finland. During the baseline surveys the following factors were determined: smoking, blood pressure, cholesterol, high-density lipoprotein cholesterol, diabetes, height, body mass index, family history of CHD and socioeconomic status. The cohorts were followed for coronary events until the end of 1994. CHD risk was about 40% higher in eastern than in southwestern Finland. The levels of most of the measured risk factors were also higher in eastern Finland. Differences in risk factor levels explained about 40% of the excess CHD risk in eastern Finland. The impact of the classical risk factors, such as smoking, cholesterol and blood pressure, on the regional difference was smaller than expected. Single risk factor measurements in our population surveys, however, may not have correctly reflected the long-term exposure of individuals to these risk factors, particularly because the surveys were carried out within a period during which these risk factors were undergoing favourable changes in the Finnish population. In addition to the classical risk factors, regional differences in body height and socioeconomic status were associated with the regional differences in CHD risk.

Association between body iron stores and the risk of acute myocardial infarction in men

BACKGROUND

Epidemiological evidence concerning the role of iron, a lipid peroxidation catalyst, in coronary heart disease (CHD) is inconsistent. We investigated the association of the concentration ratio of serum transferrin receptor to serum ferritin (TfR/ferritin), a state-of-the-art measurement of body iron stores, with the risk of acute myocardial infarction (AMI) in a prospective nested case-control study in men from eastern Finland.

METHODS AND RESULTS

Transferrin receptor assays were carried out for 99 men who had an AMI during an average 6.4 years of follow-up and 98 control men. Both the cases and the controls were nested from the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD) cohort of 1931 men who had no clinical CHD at the baseline study. The controls were matched for age, examination year, and residence. AMIs were registered prospectively. Soluble transferrin receptors were measured by immunoenzymometric assay and ferritin concentration by radioimmunoassay from frozen baseline serum samples. The mean TfR/ferritin ratio was 15.1 (SE, 2.0) among cases and 21.3 (SE, 2.2) among controls (P=.035 for difference). In logistic regression models adjusting for other strongest risk factors for AMI and indicators of inflammation and alcohol intake, men in the lowest and second lowest thirds of the TfR/ferritin ratio had a 2.9-fold (95% CI, 1.3 to 6.6, P=.011) and 2.0-fold (0.9 to 4.2, P=.081) risk of AMI compared with men in the highest third (P=.010 for trend).

CONCLUSIONS

These data show an association between increased body iron stores and excess risk of AMI, confirming previous epidemiological findings.

Lp(a) lipoprotein level predicts survival and major coronary events in the Scandinavian Simvastatin Survival Study

The Scandinavian Simvastatin Survival Study (4S) was a double-blind, randomized placebo-controlled multi-centre clinical trial of long-term Simvastatin therapy in patients with coronary heart disease who had total cholesterol levels between 5.5 and 8.0 mmol/l, comprising 4444 patients, equally distributed to a Simvastatin and a placebo group. Patients achieved a significant 30% relative reduction in overall mortality with Simvastatin therapy through a 42% relative reduction in coronary heart disease mortality. Lp(a) lipoprotein levels in Scandinavian coronary heart disease patients were strikingly higher than in healthy controls. Numbers of deaths in the Simvastatin group differed significantly between quartiles of Lp(a) lipoprotein levels, the reduction in deaths being most pronounced in the second (next to lowest) quartile. Subjects with major coronary events had significantly higher Lp(a) lipoprotein levels than subjects without such events, in all groups. The relationship between Lp(a) lipoprotein level and total mortality as well as between Lp(a) lipoprotein level and major coronary events was significantly different from zero, in logistic regression analyses. The findings show that Lp(a) lipoprotein predicts major coronary events as well as death in secondary prevention with Simvastatin. This prospective study provides independent confirmation that a high Lp(a) lipoprotein level is a significant coronary heart disease risk factor.

Relatively high coronary death and event rates in Turkish women. Relation to three major risk factors in five-year follow-up of cohort

The study describes rates of coronary heart disease death and nonfatal coronary events over five years in a cohort of random sample population and relates them to levels of three major risk factors. It is based on a longitudinal follow-up of survey conducted initially in 1990 in all geographic regions of Turkey. Two-thirds of the original cohort aged 20 years or over 2259 adults comprising 1146 women was followed up by physical examination and an ECG recording at rest. New coronary events were defined to include myocardial infarction and stable angina with or without associated myocardial ischemia developed during the follow-up period. Overall annual death rate was nine per 1000 adults. Coronary deaths numbered 55 (of which 26 were women) representing 4.1 per year and were found high in women. New coronary events were registered in 37 men and 32 women (annual rates 7.2 and 5.8 per 1000, respectively). Among male participants aged initially 40 years or over, high systolic blood pressure (> or = 130 mmHg) at baseline significantly predicted coronary death (age-adjusted risk ratio (RR) 3.3) while high cholesterol concentrations (> or = 5.2 mmol l-1) predicted new coronary events alone (RR almost 2). In women systolic pressure again strongly predicted coronary death (age-adjusted RR 3.9), whereas abnormal cholesterol levels discriminated for coronary death and new coronary events (RR around 2.3 for each). High diastolic pressure (> or = 85 mmHg) was of predictive value for the combined outcome of coronary death and events in women (RR 1.9) but not in men. Multivariate analysis by logistic regression identified systolic blood pressure in men as significant independent predictor of coronary death, while total cholesterol concentration in both genders and systolic blood pressure in men were independent predictors of the combined outcome of coronary death or nonfatal coronary events. It was concluded that known major risk factors act in similar magnitudes commensurate with the specific risk increments also in populations with essentially low cholesterol levels. The relatively high coronary morbidity and mortality in Turkish women approaching that in men may be accounted for by an inherent greater risk burden.

[Validation of "myocardial infarction" as cause of death on death certificates in Barquisimeto, Lara state, Venezuela]

Death rates due to Ischemic Heart Disease (IHD) are widely used to assess regional and national cardiovascular health status. However, their validity is questionable, essentially because they are based on death certificates (DCs). The present study was conducted in the Greater Metropolitan Area of Barquisimeto (Lara State, Venezuela), from June 1991 to July 1992. The purpose was to establish the validity of the diagnosis of myocardial infarction in DCs of intrahospital deaths. Efforts were made to locate all clinical charts and any other relevant information. To validate the diagnosis of MI in the DC we used the MONICA project criteria. During the study period a total of 247 eligible DCs were recorded. Sufficient clinical information was located for 136 cases (55%). The results were as follows: definite MI - 62 cases (45.6%); probable MI - 31 cases (22.8%); and non MI - 43 cases (31.6%). These results may indicate an overestimation of MI death rates of about 32% [95% Confidence Interval = 23.8% - 39.4%]. Since these data are from a region with an organized cardiovascular health system, it is expected that the overestimation for the rest of the country may be even higher. Thus, in order to enhance quality and accuracy of DCs, it is necessary to develop a system to improve adherence to existing norms for filling out and processing such forms.

How to define coronary heart disease in register-based follow-up studies: experience from the Helsinki Heart Study

Information on coronary heart disease (CHD) obtained from the Finnish Hospital Discharge and Cause-of-Death Registers was compared with that collected in the Helsinki Heart Study (HHS) during an 8.5-year follow-up. The purpose of the comparison was two-fold, firstly, to study the accuracy of registration of CHD and secondly, to find out what diagnostic codes to use for CHD in register-based follow-up studies. The HHS cases were used as the 'golden standard' and the CHD deaths and definite nonfatal acute myocardial infarctions (AMIs) (all diagnoses) were taken from the registers to establish the sensitivity of the Hospital Discharge and Cause-of-Death Registers combined. The sensitivity was 0.84 during the period 1980-86 and 0.87 during 1987-90, with the positive predictive values 0.94 and 0.92 respectively. The treatment effects seen in the HHS were compared with the effects that would have emerged, if register-based information only had been used with different definitions of CHD. Of the register-based calculations, the one with the definition 'all CHD deaths and hospitalizations with the ICD-8 code 410' came closest to the HHS result, with a 32% reduction (P=0.028 one-sided) of CHD incidence, while the original HHS result was a 34% reduction (P=0.008 one sided). However, when comparing Kaplan-Meier plots of cumulative hazards of CHD, the plot with a wider definition of CHD (ICD-8 and ICD-9 codes 410-414) came closest to the HHS experience, especially if revascularizations were included in the latter. Definite AMI as a single definition of CHD might thus not be sufficient when studying CHD risk, instead, at least two parallel definitions of CHD should be used.

Workplace conditions, socioeconomic status, and the risk of mortality and acute myocardial infarction: the Kuopio Ischemic Heart Disease Risk Factor Study

OBJECTIVES

This study investigated whether the association between workplace conditions and the risk of all-cause and cardiovascular mortality and acute myocardial infarction differed by socioeconomic status.

METHODS

Prospective data were used to examine these associations in 2297 Finnish men, with adjustment for prevalent diseases and biological, behavioral, and psychosocial covariates, and stratified by employment status and workplace social support.

RESULTS

Elevated age-adjusted relative hazards for all-cause mortality were found for men who reported high demands, low resources, and low income; high demands, high resources, and low income; and low demands, high resources, and low income. Similar patterns were found for cardiovascular mortality. In contrast, elevated age-adjusted relative hazards for acute myocardial infarction were observed only in men who reported high demands, low resources, and low income. These results did not differ by level of workplace social support or employment status.

CONCLUSIONS

The negative effects of workplace conditions on mortality and of myocardial infarction risk depended on income level and were largely mediated by known risk factors.

Validity of diagnoses of major coronary events in national registers of hospital diagnoses and deaths in Finland

We validated diagnoses of acute myocardial infarction (AMI) and death from coronary heart disease (CHD) found in the Finnish National Hospital Discharge Register and the Register of Causes of Death from a sample of the 29,133 men participating in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The cases were traced to hospitals and institutes performing medico-legal death cause examinations and all relevant information was collected. The cardiac events were re-evaluated according to the diagnostic criteria of the Finnish contribution to the WHO MONICA project, i.e. the FINMONICA criteria. Altogether 408 cases of non-fatal AMI (n = 217) and death from CHD (n = 191) were reviewed. In the re-evaluation 94% of them (95% confidence interval 92-96%) were diagnosed as either definite (57%) or possible (37%) AMI. Non-fatal cases were more often classified definite AMI in the review, whereas fatal cases were more often classified possible AMI. Age or trial supplementation group did not affect classification, and no secular trend was observed. In conclusion, the diagnoses of AMI and death from CHD in the registers were highly predictive of a true major coronary event defined by strict criteria, thus their use in endpoint assessment in epidemiological studies and clinical trials is justified.

Mild myocardial infarction--a classification problem in epidemiologic studies. WHO MONICA Project

In studies assessing the trends in coronary events, such as the World Health Organization (WHO) MONICA Project (multinational MONItoring of trends and determinants of CArdiovascular disease), the main emphasis has been on coronary deaths and non-fatal definite myocardial infarctions (MI). It is, however, possible that the proportion of milder MIs may be increasing because of improvements in treatment and reductions in levels of risk factors. We used the MI register data of the WHO MONICA Project to investigate several definitions for mild non-fatal MIs that would be applicable in various settings and could be used to assess trends in milder coronary events. Of 38 populations participating in the WHO MONICA MI register study, more than half registered a sufficiently wide spectrum of events that it was possible to identify subsets of milder cases. The event rates and case-fatality rates of MI are clearly dependent on the spectrum of non-fatal MIs, which are included. On clinical grounds we propose that the original MONICA category "non-fatal possible MI" could be divided into two groups: "non-fatal probable MI" and "prolonged chest pain." Non-fatal probable MIs are cases, which in addition to "typical symptoms" have electrocardiogram (ECG) or enzyme changes suggesting cardiac ischemia, but not severe enough to fulfil the criteria for non-fatal definite MI. In more than half of the MONICA Collaborating Centers, the registration of MI covers these milder events reasonably well. Proportions of non-fatal probable MIs vary less between populations than do proportions of non-fatal possible MIs. Also rates of non-fatal probable MI are somewhat more highly correlated with rates of fatal events and non-fatal definite MI. These findings support the validity of the category of non-fatal probable MI. In each center the increase in event rates and the decrease in case-fatality due to the inclusion of non-fatal probable MI was larger for women than men. For the WHO MONICA Project and other epidemiological studies the proposed category of non-fatal probable MIs can be used for assessing trends in rates of milder MI.