Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

Development and validation of an ankle brachial index risk model for the prediction of cardiovascular events

BACKGROUND

The ankle brachial index (ABI) is related to risk of cardiovascular events independent of the Framingham risk score (FRS). The aim of this study was to develop and evaluate a risk model for cardiovascular events incorporating the ABI and FRS.

DESIGN

An analysis of participant data from 18 cohorts in which 24,375 men and 20,377 women free of coronary heart disease had ABI measured and were followed up for events.

METHODS

Subjects were divided into a development and internal validation dataset and an external validation dataset. Two models, comprising FRS and FRS + ABI, were fitted for the primary outcome of major coronary events.

RESULTS

In predicting events in the external validation dataset, C-index for the FRS was 0.672 (95% CI 0.599 to 0.737) in men and 0.578 (95% CI 0.492 to 0.661) in women. The FRS + ABI led to a small increase in C-index in men to 0.685 (95% CI 0.612 to 0.749) and large increase in women to 0.690 (95% CI 0.605 to 0.764) with net reclassification improvement (NRI) of 4.3% (95% CI 0.0 to 7.6%, p = 0.050) and 9.6% (95% CI 6.1 to 16.4%, p < 0.001), respectively. Restricting the FRS + ABI model to those with FRS intermediate 10-year risk of 10 to 19% resulted in higher NRI of 15.9% (95% CI 6.1 to 20.6%, p < 0.001) in men and 23.3% (95% CI 13.8 to 62.5%, p = 0.002) in women. However, incorporating ABI in an improved newly fitted risk factor model had a nonsignificant effect: NRI 2.0% (95% CI 2.3 to 4.2%, p = 0.567) in men and 1.1% (95% CI 1.9 to 4.0%, p = 0.483) in women.

CONCLUSIONS

An ABI risk model may improve prediction especially in individuals at intermediate risk and when performance of the base risk factor model is modest.

Comparison of the attack rates of acute myocardial infarction in two Belgian towns

Comparison of the attack rates for acute myocardial infarction in two Belgian towns AMI attack rates in two Belgian towns. Belgium is divided in two main regions: Flanders in the North with a Dutch-speaking population, and Wallonia in the South with a French-speaking community. From 1982 onwards, a register of acute myocardial infarction has been in operation in Ghent, a Flemish town, and in Charleroi in Wallonia, following the procedures of the MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Diseases) study. Annual attack rates of myocardial infarction are presented for a 5-year period. During this period, the annual attack rates for men are 10-20% higher in Charleroi than Ghent. In women, the ratio between the two cities is less clear. The results of this community registers confirms the regional differences observed previously in Belgium using other epidemiological techniques.

Ankle brachial index combined with Framingham Risk Score to predict cardiovascular events and mortality: a meta-analysis

CONTEXT

Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction.

OBJECTIVE

To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction.

DATA SOURCES

Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies.

STUDY SELECTION

Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality.

DATA EXTRACTION

Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease.

RESULTS

Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women.

CONCLUSION

Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

Effect of coronary heart disease (CHD) risk factors and medications on invasive breast cancer risk in the Raloxifene Use for The Heart (RUTH) trial

1530

Background: RUTH enrolled 10,101 postmenopausal women at increased risk for major coronary events. Women were not enrolled based on their risk for breast cancer. The incidence of invasive breast cancer in the placebo group was low for this older population of women (mean age 67.5 years). The aim of this analysis was to determine whether CHD risk factors and selected cardiac medications were protective against invasive breast cancer in this population at increased risk for coronary events. Methods: Covariates assessed were baseline factors that are known CHD risk factors and selected medications ( Table ). Univariate analyses were performed for all covariates using placebo data. Results: The effect of baseline CHD risk factors and selected cardiac medications on the incidence of invasive breast cancer in women receiving placebo in RUTH (N=5057) Conclusions: In these postmenopausal women at increased risk for major coronary events, baseline CHD risk factors and selected cardiac medications assessed individually did not protect against invasive breast cancer. The low incidence of invasive breast cancer in the RUTH population does not appear to be due to the presence of CHD risk factors or use of cardiac medications.

[Table: see text]

[Table: see text]

Predictors of misreporting in an elderly population: the 'Quality of life after 65' study

OBJECTIVES

To evaluate the prevalence and identify some predictors of misreporting in an elderly Belgian population and to assess the effect of underreporting on estimated intakes of macronutrients and foods.

DESIGN

A 1-day food record was completed by 2083 adult men and women aged 65 years or more. Individuals whose energy intake was lower than 0.90 x BMR (basal metabolic rate) were defined as underreporters. Overreporting was defined as energy intake greater than 2 x BMR.

RESULTS

Underreporting and overreporting occurred in 13.6% and 7.9% of food records, respectively. Results from logistic regression models indicated that gender and body mass index (BMI) were predictors of misreporting. Whereas women were more likely to underreport energy intake, the prevalence of overreporting was higher in men. Underreporting was more prevalent among obese people and overreporting more prevalent in normal-weight subjects. Smoking status and education level did not predict underreporting; however, overreporting was more likely to occur in more highly educated subjects. A cultural difference in reporting of nutrient intakes was also found, with the percentage of underreporters being higher among Walloons compared with Flemish.

CONCLUSION

BMI seemed to be one of the most important factors in misreporting. This calls for special attention when dietary surveys are performed on obese or lean people.

Gender and regional differences in perceived job stress across Europe

BACKGROUND

Over the last 20 years stress at work has been found to be predictive of several conditions such as coronary heart disease, high blood pressure and non-specific sick leave. The Karasek demand/control/strain concept has been the most widely used in prospective epidemiological studies.

OBJECTIVES

To describe distribution in Karasek's demand/control (DC) dimensions as well as prevalence of strain in samples from different parts of Europe grouped into three regions (South, Middle, Sweden), adjusting for occupation. To describe gender differences in Karasek's DC dimensions along with strain prevalence and assess the regional stability of those differences in different occupational groups.

DESIGN

The Job stress, Absenteeism and Coronary heart disease in Europe (JACE) study, a Concerted Action (Biomed I) of the European Union, is a multicentre prospective cohort epidemiological study: 38,019 subjects at work aged 35-59 years were surveyed at baseline. Standardised techniques were used for occupation coding (International Standardised Classification of Occupations) and for the DC model (Karasek scale): five items for the psychological demand and nine items for the control or decision latitude dimensions, respectively.

RESULTS

A total of 34,972 subjects had a complete data set. There were important regional differences in the Karasek scales and in prevalence of strain even after adjustment for occupational class. Mean demand and control were higher in the Swedish centres when compared to two centres in Milano and Barcelona (Southern region) and values observed in four centres (Ghent, Brussels, Lille and Hoofddorp) in Middle Europe were closer to those observed in the Southern cities than to those obtained in the Swedish cities. Clerks (ISCO 4) and, more specifically, office clerks (ISCO 41) exhibited the smallest regional variation. In a multivariate model, the factor 'region' explained a small fraction of total variance. In the two Southern centres as well as in the four Middle European centres, men perceived marginally less job-demand as compared to women whereas the reverse was observed in the two Swedish centres. Differences were larger for control: men appeared to perceive more control at work than did women. In a multivariate model, gender explained a small fraction whereas occupational level explained a large fraction of the variance.

CONCLUSIONS

In this standardised multicentre European study Karasek's DC model showed large gender and occupational differences whereas geographic region explained a small fraction of the total DC variance, notwithstanding large differences in labour market and working conditions as pointed out by the European Commission as recently as 2000.

Application de l’approche globale de l’alimentation dans la population belge

BACKGROUND

Dietary pattern analysis has recently emerged as a new direction and a complementary approach to study the relationship between diet and morbidity or mortality. At present, two methods have been developed to construct dietary patterns: "a priori" method and "a posteriori" method.

OBJECTIVE

This paper presents the two methods and their application based on dietary data from the "Belgium Interuniversity on Nutrition and Health Study".

METHODS

A prospective study was conducted (1979-1984) in a sample of 5,225 males and 4,476 females from the Belgian population aged 25 to 74 years at the initial survey and followed for 10 years for all causes and specific mortality. Dietary data was collected by a 24-hour recall and for a sub-sample also by a 7 day-diet record. The "a priori" method was used by calculating an index based on the national dietary guidelines. We used the principal component analysis to identify dietary patterns a posteriori. We conducted a first principal component analysis using the data from the 24-hour recall and a second on the data collected by the 7 day-record.

RESULTS

Both of the currently used approaches for extracting dietary patterns have advantages and limitations. We applied first the "a priori" approach by calculating an Index (IAR) which measures the adherence of the sample to the Belgian dietary guidelines. We obtained an index that ranged from 0 to 8, a higher score represented a "healthier diet". The index mean (sd) was 3.7 (+/- 1.2) for the entire sample with a significantly higher IAR for women. Using factor analysis, we identified 8 dietary patterns for men and for women. These were difficult to translate in terms of dietary intake profile. Inversely, with the factors identified with the 7 day record, we could find a "western" dietary profile and a "prudent" profile.

CONCLUSION

Dietary pattern analysis offers the opportunity to evaluate the overall quality of the diet. The dietary profiles constructed by the two approaches should be related to morbidity or mortality in order to evaluate their predictive capacity.

Perceived job stress and incidence of coronary events: 3-year follow-up of the Belgian Job Stress Project cohort

Psychosocial characteristics have been linked to coronary heart disease. In the Belgian Job Stress Project (1994-1999), the authors examined the independent role of perceived job stress on the short-term incidence of clinical manifest coronary events in a large occupational cohort. A total of 14,337 middle-aged men completed the Job Content Questionnaire to determine the dimensions of the extended job strain model, job demands, decision latitude, and social support. Jobs were categorized into high strain, low strain, active jobs, and passive jobs. During the 3-year follow-up, 87 coronary events were registered. At baseline, 17% of workers experienced high strain. Job demands and decision latitude were not significantly related to the development of coronary heart disease after adjustment for covariates. The 38% risk excess among subjects classified in the high-strain category did not reach statistical significance. However, coronary heart disease incidence was substantially associated with the social support scale independently of other risk factors, with an adjusted hazard ratio of 2.4 (95% confidence interval: 1.4, 4.0) between extreme tertiles. No convincing evidence for an association of job demands, decision latitude, or job strain with the short-term incidence of coronary heart disease was found. However, our study underscores the importance of a supportive social work environment in the prevention of coronary heart disease.

Occupational stress and incidence of sick leave in the Belgian workforce: the Belstress study

CONTEXT

Sick leave is a major problem in public health. The Karasek demands/control/social support/strain (JDCS) model has been largely used to predict a wide range of health outcomes and to a lesser extent sickness absence.

STUDY OBJECTIVE

The aim of the study was to test the predictive power of the JDCS model in relation with one year incidence of sick leave in a large cohort of workers.

DESIGN AND SETTING

Cohort study conducted between 1994 and 1998 in 25 companies across Belgium.

PARTICIPANTS

A total of 20 463 workers aged 35 to 59 years were followed up for sick leave during one year after the baseline survey.

OUTCOMES

The outcomes were a high sick leave incidence, short spells (>/=7 days), long spells (>/=28 days), and repetitive spells of sickness absence (>/=3 spells/year).

MAIN RESULTS

Independently from baseline confounding variables, a significant association between high strained jobs with low social support and repetitive spells of sickness absence was observed in both sexes with odds ratios of 1.32 (99% CI, 1.04 to 1.68) in men and 1.61 (99% CI, 1.13 to 2.33) in women. In men, high strained jobs with low social support was also significantly associated with high sick leave incidence, and short spells of sick leave with odds ratios of 1.38 (99% CI, 1.16 to 1.64) and 1.22 (99% CI, 1.05 to 1.44) respectively.

CONCLUSIONS

Perceived high strain at work especially combined with low social support is predictive of sick leave in both sexes of a large cohort of the Belgian workforce.

Serum selenium and cancer mortality: a nested case-control study within an age- and sex-stratified sample of the Belgian adult population

OBJECTIVE

To study the predictive power of serum selenium with regard to cancer mortality in a large sample of the Belgian population given the lack of coherence in the results of observational epidemiological studies in this domain.

DESIGN

A prospective case-control study within a stratified sample of the Belgian male and female population.

SUBJECTS

A total of 201 cases randomly selected from all cancer deaths (N=343) during a 10-y mortality follow-up of a large age- and sex-stratified sample of the total Belgian population aged 25-74 y were matched for age and gender with 603 controls.

STATISTICS

Conditional logistic regression for both univariate and multivariate analyses using tertile distribution of serum selenium in controls. Odds ratios (ORs) are adjusted for 10 baseline characteristics.

RESULTS

Unadjusted ORs of cancer deaths taking the highest tertile of serum selenium as a reference: in male subjects T1/T3 is 2.2 (CI 1.3-3.7) (P for trend 0.011), whereas in female subjects a nonsignificant OR of 0.8 is observed. In multivariate analyses, no significant modifications of the ORs are observed for the predictive relation of serum selenium with cancer mortality. Besides serum selenium, beta-carotene intake and smoking are independent predictors in male subjects.

CONCLUSIONS

In this nested case-control study of a stratified sample from the Belgian population, serum selenium is an independent predictor of cancer mortality in male subjects only, in a country with rather high serum selenium levels with respect to most other European countries.

Obesity, body fat distribution and incidence of sick leave in the Belgian workforce: the Belstress study

OBJECTIVES

In many studies, obesity has been associated with morbidity or mortality, but only a few have studied the relation between obesity and sick leave. Our aim is to analyse the independent effects of both adiposity and body fat distribution in relation to the 1-y incidence of sick leave in a large cohort of male and female workers covering a variety of occupations, taking into account a wide range of socio-demographic, behavioural and bioclinical variables.

DESIGN AND SETTING

The baseline survey of the Belstress study was conducted in 25 companies across Belgium between 1994 and 1998. A cohort of 20 463 workers (15 557 males and 4906 females) aged 35-59 y was followed for absenteeism during 1 y. The 75th percentile of the distribution of the total annual sickness days was used as a cutoff to classify the workers with a high 1-y incidence rate of sick leave. The relation between sick leave and both obesity and body fat distribution assessed by the body mass index (BMI) and the waist circumference, respectively, was analysed by multivariate logistic regression models.

RESULTS

Using a backward procedure based on the likelihood ratio, we found central abdominal fatness to be an independent predictor of sick leave in both genders (high sick-leave incidence and long spells), but not BMI. In men, the odds ratios was 1.31 (99% CI 1.12-1.52, P<0.0001) and in women it ranged from 1.32 (99% CI 1.03-1.70, P=0.005) to 1.47 (99% CI 1.14-1.90, P<0.0001). Two baseline covariables, respiratory problems and perceived health, are confounders or mediators.

CONCLUSIONS

In this study, body fat distribution was associated with a high annual sick-leave incidence and long spells of sickness absence. If this link is reversible, employers may benefit from programs aiming at the prevention and treatment of central obesity.

Job conditions and fibrinogen in 14226 Belgian workers: the Belstress study

AIMS

To investigate the relationship between fibrinogen and stressful work conditions, where perceived strain is defined by the simultaneous presence of high psychological demands and low control, according to Karasek's Demand/Control/(Social Support) model.

METHODS AND RESULTS

A cross-sectional study was realized between 1994 and 1998 in 24 Belgian enterprises, on 16335 male and 5084 female middle-aged workers of different Belgian companies participating in the Belstress study. This study confirmed the well-documented bivariate relationship between plasma fibrinogen levels and gender, age, educational level, smoking, obesity, physical activity, alcohol consumption, total cholesterol, HDL-cholesterol, arterial hypertension and diabetes. No independent multivariate relationship was observed between job control, psychological job demands or social support at work and plasma fibrinogen, but after stratification a positive association (P< or =0.05) was observed between psychological job demands and plasma fibrinogen for males in the lowest educational level. Moreover a positive statistically significant association between job strain and plasma fibrinogen was observed in males but not in females. After stratification for educational level this association remained significant for males especially in the lowest educational level (P< or =0.001) and became significant for females in the middle educational level. CONCLUSIONS; As suggested in our study and others, plasma fibrinogen could be one of the potential mediators explaining the relationship between job stress and coronary heart disease.

Parameters of inflammation and infection in a community based case-control study of coronary heart disease

BACKGROUND

increased levels of systemic inflammatory markers appear to be related to coronary heart disease (CHD) both in asymptomatic individuals and in subjects with established CHD. Whether these associations are related to confounding coronary risk factors or are explicable through chronic infectious conditions is not clear.

OBJECTIVES

(1) to determine whether subjects with stable CHD differ from normal controls in inflammatory markers (CRP, SAA and fibrinogen) and/or in serostatus of four infectious agents (Helicobacter pylori, Chlamydia pneumoniae, CMV and EBV), independent of classical coronary risk factors. (2) To determine whether these inflammatory markers are related to the serostatus against these four infectious agents either in patients with CHD or in normal subjects.

METHODS

in a large epidemiologic survey, 446 out of 16307 men at work, aged 35-59 years, had antecedents of myocardial infarction, CABG or PTCA or had prominent Q/QS waves on their resting ECG. They were compared with double the number (n=892) of men, matched for age, educational level and industry. Inflammatory biomarkers (CRP, fibrinogen and SAA) and antibodies against H. pylori, C. pneumoniae, CMV and EBV were measured, besides classical coronary risk factors.

RESULTS

in univariate analyses, cases had higher CRP, fibrinogen and SAA levels than controls, but no differences were observed in serumantibody levels to any of the infectious agents. Markers of previous infections were not related to inflammatory biomarkers. In multivariate analyses CRP was significantly different between cases and controls independent of differences in other coronary risk factors and in the use of lipid lowering drugs and antiplatelet aggregants.

CONCLUSIONS

in men at work with CHD, CRP levels are significantly different from controls, independent of known risk factors. No association was found between inflammatory biomarkers and positive serostatus against four infectious agents, neither in the patients nor in the healthy controls.

[Relation between uricemia and total, cardiovascular and coronary mortality in both genders of non-selected sample of the Belgium population]

BACKGROUND

Despite more than 40 years of research on the prognostic value of hyperuricemia in relation to all-causes cardiovascular and coronary mortality, no clear consensus appears in the medical literature. Moreover, the observed relationship between hyperuricemia and the incidence of coronary heart disease mortality is related to gender. However, prospective studies including both genders are rare.

METHODS

A prospective study was conducted in a random sample of 5225 males and 4476 females from the Belgian population aged 25 to 74 years at the initial survey and followed for 10 years for all-causes and specific mortality.

RESULTS

The number of observed total, cardiovascular, and coronary heart disease deaths were 648 and 239, 150 and 225, and 96 and 51 in males and females respectively. At multivariate analysis, uricemia was significantly correlated with all-causes mortality in males whereas a tendency was observed in females. The same diverging association was observed for cardiovascular mortality. However, for coronary heart disease mortality, there was a very significant correlation only in females.

CONCLUSIONS

Our findings confirm the observed gender-related differences in the relation of hyperuricemia with all-causes and coronary heart disease mortality. We propose possible pathogenic mechanisms concerning the relationship with coronary heart disease mortality observed only in females.

Design and methods of the Raloxifene Use for The Heart (RUTH) study

Raloxifene is a selective estrogen receptor modulator that lowers total and low-density lipoprotein (LDL) cholesterol, reduces the risk of vertebral fracture, and is associated with a reduced incidence of invasive breast cancer in postmenopausal women with osteoporosis. The Raloxifene Use for The Heart (RUTH) trial is designed to determine whether raloxifene 60 mg/day compared with placebo: (1) lowers the risk of the coronary events (coronary death, nonfatal myocardial infarction [MI], or hospitalized acute coronary syndromes other than MI); and (2) reduces the risk of invasive breast cancer in women at risk for a major coronary event. RUTH is a double-blind, placebo-controlled, randomized clinical trial of 10,101 postmenopausal women aged > or =55 years from 26 countries. Women are eligible for randomization if they are postmenopausal and have documented coronary heart disease (CHD), peripheral arterial disease, or multiple risk factors for CHD. Use of estrogen within the previous 6 months is an exclusion factor. The study will be terminated after a minimum of 1,670 participants experience a primary coronary end point. Secondary end points include cardiovascular death, myocardial revascularization, noncoronary arterial revascularization, stroke, all-cause hospitalization, all-cause mortality, all breast cancers, clinical fractures, and venous thromboembolic events, in addition to the individual components of the composite primary coronary end point. RUTH will provide important information about the risk-benefit ratio of raloxifene in preventing acute coronary events and invasive breast cancer, as well as information about the natural history of CHD in women at risk of major coronary events.

Haptoglobin polymorphism as a risk factor for coronary heart disease mortality

OBJECTIVES

the aim of our study was to evaluate the independent role of the haptoglobin (Hp) polymorphism as a risk factor for coronary heart disease (CHD) mortality.

METHODS

within the framework of the longitudinal part of the Belgian Interuniversity Research on Nutrition and Health (BIRNH) survey, a nested case-control study design was performed through matching the 107 deaths from CHD, occurring within a 10-year follow-up period, with three controls for age and gender.

RESULTS

the distribution of the Hp types was found to be in Hardy-Weinberg equilibrium. Conditional logistic regression analysis for matched sets revealed that the Hp polymorphism was significantly associated with CHD death. Rather surprisingly, the finding was that Hp 1-1 individuals were at doubled risk for CHD mortality compared with the others, the odds ratio being 2.09 (95% CI: 1.22-3.60). The association was independent from other classical cardiovascular risk factors and the Hp concentration, and of comparable magnitude between men and women. Moreover, evaluating the interaction term in a multiplicative model showed that the Hp type did not play a synergistic role in the prognostic value of established cardiovascular risk factors.

CONCLUSION

in contrast to the findings from cross-sectionally based studies, the results from this longitudinal study show that Hp 1-1 individuals are at elevated risk for CHD mortality.

Prevalences of ECG findings in large population based samples of men and women

OBJECTIVE

To obtain accurate estimates of the prevalence of ECG abnormalities in the general population and to describe them in relation to age, sex, and some lifestyle related factors.

DESIGN

The results were obtained from the records of 47 358 men and women participating in four large Belgian epidemiological studies during the past 30 years. All tracings were read and coded by two trained cardiologists on the basis of Minnesota code criteria.

RESULTS

Prevalences of coronary heart disease and abnormal ECG findings rose exponentially with age in both sexes, with the exception of atrioventricular block and the Wolff-Parkinson-White (WPW) syndrome. Major ECG findings were observed in 6.0% of all men and 4.3% of women, resulting in a significant adjusted sex ratio of 1.66 (95% confidence interval 1.46 to 1.88). The prevalence of minor ECG changes was slightly higher among men (10.4% v 9.5% in women). The occurrence of ischaemia-like findings on the ECG was comparable between men and women (9.0% v 9.8%). Independent of age, smoking, obesity, diabetes, employment status, positive history of angina or infarction, and region, there were significantly higher prevalences of Q/QS patterns, left ventricular hypertrophy, left axis deviation, arrhythmias, and atrial fibrillation or flutter in men than in women. Right bundle branch block and WPW syndrome both occurred 3.5 times more often in men, while the prevalence of left bundle branch block was comparable between the sexes.

CONCLUSIONS

The large sample size allowed a precise description of the most important ECG abnormalities. These are not rare in the adult population and most are strongly age related. Sex differences occur with some, but not all, abnormalities. The less common ECG abnormalities were more often observed among men.

Trends and regional differences in coronary risk factors in two areas in Belgium: final results from the MONICA Ghent-Charleroi Study

OBJECTIVE

To study regional differences and trends in coronary risk factors and in predicted coronary risk calculated on the basis of multiple logistic function equations for the general population aged 25-64 years in two areas in Belgium during the period 1985-1992.

DESIGN

A comparison of cross-sectional data on coronary risk factors between two cities and different survey periods.

METHOD

In the cities of Ghent (in Flanders) and Charleroi (in Walloonia) in Belgium, three consecutive cross-sectional age-stratified and sex-stratified random samples of 2000 subjects each were selected from the general population. We studied their coronary risk factors between 1985 and 1992. The field work was carried out according to the protocol of the international WHO-MONICA project.

RESULTS

We observed a significant decrease in the prevalence of smoking among men in the two cities over the three surveys, while a gradual increase in diastolic blood pressure for all subgroups in Ghent was seen (this was statistically significant for men aged 45-64 years and women aged 25-44 years). The overall coronary risk predicted on the basis of multiple-logistic-function equations did not however, exhibit significant trends over time in either city. Comparisons between the two centres revealed significantly higher mean serum levels of total cholesterol in Charleroi than in Ghent (for all subgroups except women aged 45-64 years) and significantly higher mean systolic blood pressures in Charleroi for all subgroups defined in terms of age and sex. Prevalences of hypertension in Ghent were significantly lower than those in Charleroi for individuals aged 25-44 years, while the prevalence of obesity in all subgroups in Ghent was also significantly lower. The overall predicted coronary risk in Charleroi was also significantly higher, except for men aged 45-64 years. The differences in mean predicted risk ranged from 5.0% for men aged 45-64 years to 21.2% for women aged 45-64 years.

CONCLUSIONS

From the data in this article it seems that the trends in overall coronary risk profiles in Ghent and Charleroi are not in accordance with the observed trends in incidence of coronary heart disease (CHD) in these two cities. On the other hand, the differences in predicted coronary risk between the two cities are in the same direction as the observed differences in incidence of CHD between the two cities, but are however too small to explain fully the observed difference in incidence of CHD between the two centres.

Multifactorial approach to the prevention of coronary heart disease: from computer to paper and pencil?

BACKGROUND

In Europe the multifactorial clinical approach to the prevention of coronary heart disease is based on the Framingham equation presented in graphical form including age, sex, level of total serum cholesterol, systolic blood pressure and smoking.

OBJECTIVE

To propose a straightforward paper-and-pencil score (Global Coronary Risk Score) including level of high-density lipoprotein cholesterol for the Belgian or more broadly western European population derived from 10-year follow-up mortality of a Belgian national population sample.

RESULTS

This score has the same predictive power as the Framingham equation both for men aged 35-74 years and for women aged 50-74 years. It gives a ranking of subjects into four groups according to their relative risks.

CONCLUSION

Coronary Risk Score is user friendly and probably has pedagogical virtues.

[The decision to treat based on epidemiological methodology: the paradigm of hypercholesterolemia]

The author reviews the epidemiological methods, both non experimental and experimental, founding evidence-based medicine. As an example, he reviews the evolution of the scientific knowledge about the relationship between hypercholesterolemia and coronary heart disease and about the determinants of the serum cholesterol concentration. Epidemiology studies the causal chain between exposure and event (sickness) and proposes, within the framework of primary and secondary prevention of coronary heart disease, interventions to interrupt the causal chain at a given level.

Parental history of premature coronary heart disease mortality and signs of ischemia on the resting electrocardiogram

OBJECTIVES

Here we explore the association between a family history of premature coronary heart disease (CHD) death and ischemic electrocardiogram (ECG) findings in the offspring.

BACKGROUND

In the general population, signs of ischemia are found on the resting ECG in about 10% of middle-aged men and women. Their independent predictive value for CHD morbidity and mortality has been shown in several studies.

METHODS

Our results are based on cross-sectional data from three large epidemiological studies performed in Belgium during the past two decades: the Belgian Heart Disease Prevention Project (n = 8,145), the Belgian Interuniversity Research on Nutrition and Health survey (n = 7,625) and the MONICA project (n = 3,193). A parental history of fatal CHD was considered premature if the father died from CHD before age 60 or the mother before age 70. Ischemic ECG findings were defined according to Minnesota Code criteria I(1-3), IV(1-3), V(1-3) or VII1.

RESULTS

Subjects with a parental history of premature CHD death were found to have experienced significantly more frequently symptomatic CHD. After exclusion of symptomatic individuals, no major differences in lifestyle-related risk factors were found between the groups with and without a parental history of premature fatal CHD. After multivariate adjustment for age, smoking, body mass index and sex, the odds ratios (and 95% confidence interval [CI]) for ECG ischemia associated with a positive parental history of premature death were 1.42 (1.10-1.82), 1.47 (1.16-1.88) and 1.37 (0.78-2.41) in the three studies. Additional adjustment for systolic blood pressure, total cholesterol and, if available, lifestyle-related factors did not alter the magnitude of the odds ratios. Overall, in men aged 45 to 64 years, ECG ischemia was significantly more frequent (36% excess) in those with positive parental history.

CONCLUSIONS

Subjects in whom one or both parents died prematurely from cardiac-related diseases have signs of ischemia more frequently on their electrocardiogram, and this is independent of other risk factors.

Epidemiology of risk factors for hypertension: implications for prevention and therapy

We review the present knowledge of risk factors for arterial hypertension. Both genetic and environmental factors as well as their interaction and biological plausibility are reviewed. Recent data confirm that the interaction of genetics with multiple environmental risk factors explains the high prevalence of hypertension in the industrialised countries. The most important modifiable environmental risk factors are high salt intake, alcohol intake, obesity and low physical activity. The role of stress in the aetiology of high blood pressure is still under investigation, but recent clinical experimental and epidemiological data have shed light on how stress could be related to hypertension. The implications for prevention and treatment are discussed both at the population and individual levels. The population approach involves a public health policy aiming at modification of the major risk factors. The individual approach involves nonpharmacological measures to prevent the development of hypertension and to treat high normal blood pressure and mild hypertension with no additional cardiovascular risk factors. Pharmacological treatment of hypertension in most individuals should use agents that have been proven to be effective in randomised controlled trials with 'hard' endpoints such as cardiovascular and cerebrovascular morbidity and mortality.

Trends in coronary heart disease in two Belgian areas: results from the MONICA Ghent-Charleroi Study

SETTING

As part of the WHO-MONICA study, acute coronary events have been registered from 1983 until 1992 in the general population aged 25-69 years in two Belgian cities--Ghent in the northern Dutch speaking part of Belgium and Charleroi in the southern French speaking part. Registration of events was done according to an international standard protocol.

OBJECTIVE

To study trends in total, fatal and non-fatal event rates and trends in case fatality rates in these two cities.

MAIN RESULTS

Incidence of CHD was on average 50% higher in Charleroi compared with Ghent in both men and women (attack rate ratio Charleroi/Ghent was 1.5 in both sexes). In both men and women, diverging trends were observed between the two cities for total and non-fatal event rates, while parallel declining trends were observed in fatal event rates and in case fatality rates. In both sexes, total attack rates showed a significant decrease in Ghent and a significant increase in Charleroi. Also in the two sexes, attack rates of non-fatal events increased significantly in Charleroi and remained stable in Ghent. Attack rates of fatal events decreased significantly in men and women in Ghent and in men in Charleroi. Both "total" and "in hospital" case fatality rates declined significantly in both sexes in the two cities.

CONCLUSIONS

Important differences in coronary heart disease (CHD) incidence and CHD trends between Ghent and Charleroi were observed. These differences and trends are interpreted in the context of existing and still growing differences in the overall socioeconomic situation between the north and the south of the country. On the other hand, the efficacy of medical treatment of CHD is comparable in the two regions, as reflected by similar figures and trends for case fatality rates.

Primary and secondary prevention of coronary artery disease: a follow-up on clinical controlled trials

Most probably the decennia of the 1990s will be called the 'statin decennia' in the history of coronary heart disease prevention. Statins are effective, both in primary and secondary prevention of coronary heart disease, in middle-aged and older (< 76 years) men and women, in both diabetics and non-diabetics with coronary heart disease. Statins used in secondary prevention of coronary heart disease significantly reduce the risk of stroke. They also reduce daily attacks of myocardial ischemia. Pathogenetic pathways leading to 'biological plausibilities' of the statins favourable effects are multiple, which explains their rapid (less than 1 year) influence on coronary events. Until the results from new event trials become available, fibrates have very few indications as first line drug therapy in dyslipidemia. They should be considered in combined therapy with statins. The scientific evidence with statins is overwhelming and the question is no longer 'who should we treat?' but 'who can society afford to treat?'. Health economics are indeed pivotal in the use of statins and public health authorities have to find answers according to their resources or innovative strategies, including new aspects in dietary advice (the 'Mediterranean diet'?).

Prognostic value of ECG findings for total, cardiovascular disease, and coronary heart disease death in men and women

OBJECTIVE

To study abnormalities in the resting ECG as independent predictors for all cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in a population based random sample of men and women, and to explore whether their prognostic value is different between sexes.

DESIGN AND SUBJECTS

An age and sex stratified random sample was selected from the total Belgian population aged 25 to 74 years. Baseline data were gathered and resting ECGs were classified according to Minnesota code criteria. The sample was then followed for at least 10 years with respect to cause specific death. Results are based on observations from 5208 men and 4746 women free from prevalent CHD at the start of the follow up period.

RESULTS

Although the prevalence of major abnormalities in general was comparable between sexes, women had more ischaemic findings, ST segment changes, and abnormal T waves on their baseline ECG, while men showed more arrhythmias, bundle branch blocks, and left ventricular hypertrophy. Fitting the multiplicative effect on subsequent mortality between all ECG classifications under study and sex indicated that the prognostic value of ECG changes was equal in women and men. Independently of other risk factors and other major ECG changes, almost all ECG classifications were significantly related to all cause, CVD, and CHD mortality. The most predictive ECG findings for CVD death were ST segment depression (risk ratio (RR) 4.71), major ECG findings (RR 3.26), left ventricular hypertrophy (RR 2.79), bundle branch blocks (RR 2.58), T wave flattening (RR 2.47), ischaemic ECG findings (RR 2.35), and arrhythmias (RR 2.15). The prognostic value of major ECG findings for CVD and CHD death was more powerful than well established cardiovascular risk factors.

CONCLUSIONS

Abnormalities in the baseline ECG are strongly associated with subsequent all cause, CVD, and CHD mortality. Their predictive value was similar for men and women.

Prevalence, awareness, treatment and control of arterial hypertension in an elderly population in Belgium

OBJECTIVE

To study the prevalence, awareness, treatment and control of arterial hypertension in the elderly population in Belgium.

STUDY GROUP

An age- and sex-stratified sample of 2212 Belgian subjects aged 65 years or more, selected from the original cohort of the Belgian Interuniversity Research on Nutrition and Health (BIRNH) study; participation in this follow-up study was 72.6%.

METHODS

Blood pressure (BP) was measured at home by trained technicians using a standard protocol. Isolated systolic hypertension (ISH) was defined as a systolic BP > or =160 mm Hg and a diastolic BP <95 mm Hg. Diastolic hypertension was defined as a diastolic BP > or =95 mm Hg. The total hypertensive population was defined as all those with ISH, diastolic hypertension and with BPs <160-95 mm Hg but currently taking antihypertensive drugs. Awareness and treatment status were investigated through a structured interview.

RESULTS

The prevalence of arterial hypertension was 43.9%, higher in women than in men and increasing with age in women; elevated BP was found in 22.3 to 28.6% of the participants varying by age and sex. In the >75-year-old subjects this elevation was in two-thirds of the cases due to ISH; 84% of all female hypertensives were aware of the condition compared to 68% in men. Treatment advice had been given in a majority of the aware subjects and two-thirds of all treated persons was under control. Among a variety of independent variables and besides the gender difference, awareness was only related to smoking and to depression while control differed by region of residence.

CONCLUSION

Arterial hypertension is highly prevalent in this elderly population; awareness and BP control are within acceptable ranges but there is still room for improvement, particularly in elderly men.

Prognostic value of ischemic electrocardiographic findings for cardiovascular mortality in men and women

OBJECTIVES

The aim of this study was to investigate the independent prognostic value of ischemic electrocardiographic (ECG) findings for cardiovascular mortality and to evaluate a possible sex-differential in this regard.

BACKGROUND

In previous reports, ST segment and T wave changes on the resting ECG were described as independent risk factors for development of coronary heart disease. Although more prevalent in women, they are often given less clinical importance than in men.

METHODS

Ten-year follow-up data from the Belgian Interuniversity Research on Nutrition and Health study were used. The results presented here are based on ECGs of the 4,797 men and 4,320 women, aged 25 to 74 years, who were free of angina pectoris at the start of follow-up, had no history of myocardial infarction (MI) and showed no Q wave evidence of an old MI on their ECG.

RESULTS

At baseline, the age-standardized prevalence of an "ischemic ECG" (Minnesota codes I3, IV1-3, V1-3 or VII1) was 8.4% in men and 10.6% in women. Cardiovascular mortality rates in men and women with an ischemic ECG were respectively 7.7 and 2.6 per 1,000 person-years, compared with 2.3 and 1.0 in those with no such ECG findings. After correction for the potential confounding effects of established cardiovascular disease (CVD) risk factors, the multivariately adjusted risk ratios were 2.45 (95% confidence interval [CI]: 1.70 to 3.53) for men and 2.16 (95% CI: 1.30 to 3.58) for women. Testing the interaction between an ischemic ECG and sex on CVD mortality revealed that the risk ratios were not significantly changed (p=0.95). The etiologic fraction of CVD deaths attributable to an ischemic ECG was estimated as 19.3% for men and 22.4% for women. Both men and women with major ischemic findings in their baseline electrocardiogram (Minnesota codes IV1,2, V1,2 or VII1) had a fourfold increased risk of CVD death.

CONCLUSION

These results support the hypothesis that women with ischemic ECG findings are at the same increased risk for CVD mortality as men.

Hormone and nonhormone therapy for the maintenance of postmenopausal health: the need for randomized controlled trials of estrogen and raloxifene

Multiple health benefits have been postulated for the long-term use of hormone therapy in postmenopausal women, most notably for prevention of osteoporotic fractures and coronary heart disease, as well as several risks, including cancer of the breast and uterus and venous thromboembolism. Cardiovascular disease is the most common cause of death among postmenopausal women. If real, the reduction in risk of coronary heart disease by hormone use suggested by observational studies would likely outweigh the risks. The decision to initiate and maintain hormone therapy is complicated by uncertainties about estrogen's true benefits and risks. Raloxifene, a selective estrogen receptor modulator (SERM), appears to have many of the benefits of estrogen without the cancer risks. It is not known if SERMs can provide significant cardiovascular protection. This article reviews the relation of use of postmenopausal hormones and raloxifene to women's health and addresses the need for large randomized trials to quantify the effect of both postmenopausal estrogen and raloxifene on cardiovascular health.

Misclassification of coronary heart disease in mortality statistics. Evidence from the WHO-MONICA Ghent-Charleroi Study in Belgium

STUDY OBJECTIVE

To validate the Belgian vital statistics for coronary heart disease (CHD) on the basis of an independent acute myocardial infarction (AMI) register, carried out as part of the WHO-MONICA project.

DESIGN

Records of fatal cases of AMI in the WHO-MONICA register were individually linked to the corresponding death certificates.

SETTING

Since 1983, the WHO-MONICA Collaborating Centre Ghent/Charleroi registers all fatal and non-fatal AMI in the age group 25-69 years in two geographical areas, Ghent in the northern Dutch speaking part and Charleroi in the southern French speaking part of Belgium. Registration is done according to the MONICA protocol. The official vital statistics in Belgium are published on a yearly basis. They are essentially a reflection of the "underlying" causes of death, coded according to the 9th revision of the International Classification of Diseases (ICD). The study was undertaken in the period 1983-1991.

MAIN RESULTS

Out of a total of 741 (Ghent) and 934 (Charleroi) well documented MONICA fatal cases of AMI, 492 (66.4%) and 641 (68.6%), respectively, were officially labelled as CHD (ICD code 410-414); 438 (59.1%) and 385 (41.2%), respectively, were officially labelled as AMI (ICD code 410). A substantial fraction of the MONICA AMI cases--27.1% in Ghent and 38.2% in Charleroi--was coded as "other forms of CHD" (ICD 411-414) or as "other forms of heart disease" (ICD 420-429). The remaining MONICA AMI cases--13.8% in Ghent and 20.6% in Charleroi--were classified in either very aspecific (for example, atherosclerosis, ICD 440) or totally unrelated ICD codes (for example, neoplasm, ICD 140-239).

CONCLUSIONS

It is concluded from the results in this paper that a substantial part of all deaths caused by CHD in Belgium are labelled with incorrect ICD codes and are therefore misclassified in the official mortality statistics for Belgium. This is partly caused by a "drainage" of cases towards less specific CHD related ICD categories. A considerable fraction, however, seems to be absolutely misclassified.

Is low serum chloride level a risk factor for cardiovascular mortality?

BACKGROUND

Serum chloride level is routinely assayed in clinical laboratories in the management of patients with kidney disorders and with metabolic diseases. It is a biological parameter that is easily, precisely and relatively cheaply measured. The epidemiological features of serum chloride levels have not been studied before.

METHODS

For the random sample of men and women from the Belgian Interuniversity Research on Nutrition and Health aged 25-74 years, free of symptomatic coronary heart disease at baseline, serum chloride concentrations were measured, among those of other electrolytes. The cohort was followed up for 10 years with respect to subsequent cause-specific mortality.

RESULTS

The results are based on observations of 4793 men and 4313 women. According to Cox regression analysis serum chloride level was one of the strongest predictors of total, cardiovascular disease (CVD) and non-CVD mortalities independently of age, body mass index, sex, smoking, systolic blood pressure, levels of total and high-density lipoprotein cholesterol, uric acid, serum creatinine and serum total proteins and intake of diuretics. This relation was proved to be independent of levels of other serum electrolytes and similar for men and women. The estimated adjusted risk ratio for CVD death for subjects with a serum chloride level < or =100 mmol/l compared with those with levels above that limit was 1.65 (95% confidence interval 1.06-2.57) for men and 2.16 (95% confidence interval 1.11-4.22) for women. The study of adjusted risk ratios for four groups of subjects defined on the basis of their baseline serum chloride levels revealed a decreasing log-linear 'dose-response' relation to total and cardiovascular mortalities.

CONCLUSION

This s the first report from a population-based study to indicate that there is an association between serum chloride level and the incidence of total, CVD and non-CVD mortalities. The risk ratio for CVD mortality associated with a low serum chloride level was comparable to or higher than those observed for well-established CVD risk factors.

Epidemiological aspects of high density lipoprotein cholesterol

Most of the results from epidemiologic studies support the general idea that high density lipoproteins (HDL) cholesterol is inversely related to coronary heart disease (CHD) incidence. Results from the literature and from a large cohort study in Belgium (the BIRNH study) are used to describe the distribution and the major determinants of HDL cholesterol. HDL cholesterol is influenced by a variety of biologic, environmental and behavioral characteristics. Results of a 10-year mortality follow-up of the BIRNH study are presented and compared to those observed in other large cohort studies. The inverse relationship between HDL cholesterol and CHD is confirmed, although the strength of the association varies between studies and is weakened after adjustment for other coronary risk factors. The results from the BIRNH study also suggest that the relation between HDL cholesterol and CVD mortality is curvilinear. At present, only indirect evidence is available to support the idea that raising HDL cholesterol is useful in primary and secondary prevention of CHD.

Trends in the prevalence, detection, treatment and control of arterial hypertension in the Belgian adult population

OBJECTIVES

To discuss changes during the past decades in the prevalence and in the patterns of detection, treatment and control of arterial hypertension in the general Belgian population aged 25-64 years.

DESIGN

Data from two cross-sectional cardiovascular disease risk factor surveys of the general population aged 25-64 years during the first and second halves of the 1980s (the Belgian Inter-university Research on Nutrition and Health study of 1980-1984 and the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Diseases study of 1985-1992) are compared.

PARTICIPANTS

Age-stratified and sex-stratified random samples from the general population yielded 9372 participants in the former study and 4904 participants in the latter.

METHODS

In both studies, blood pressure measurements and other variables were collected in the same standardized way and by the same observers.

RESULTS

For both sexes, overall age-standardized prevalences of hypertension (subjects with systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg or currently being administered antihypertensive drug treatment) were found to be significantly (P< 0.001) higher in the former than they were in the latter study. A significant decline in population mean systolic blood pressure values was observed for both sexes on going from the former data to the latter (falls of 6.0 and 7.3 mmHg for men and women, respectively, P< 0.01). In log-linear models, adjusted for age, a highly significant (P< 0.0001) favourable shift in the population distribution over the various categories of detection, treatment and control of hypertension was observed. This trend exhibited a significant sex difference, however, there being a much more favourable trend for women.

CONCLUSIONS

In Belgium, favourable trends in the prevalence and in the patterns of detection, treatment and control of arterial hypertension and in the levels of systolic blood pressure were observed. The so-called 'rule of halves' is no longer valid.

[Hypercholesterolemia in Belgium in 1996: an epidemiological viewpoint]

The authors review the epidemiological evidence linking causally the level of blood cholesterol to coronary heart disease. The evidence is based both on analytical and experimental epidemiology. They review also the two strategies of prevention: the strategy of screening for the detection of "high risk" subjects and the "population" or mass approach. The distribution of blood cholesterol in Belgium according to the Belgian Interuniversity Research on Nutrition and Health (BIRNH) data is presented. Finally, blood cholesterol is placed within a multifactorial prevention perspective using the Framingham equations. The multifactorial approach is now based on different instruments among which the graphs published by the European Society of Cardiology which are "user friendly".

[20 years of cardiovascular epidemiology. The epidemiologist's viewpoint]

The author reviews the evolution of cardiovascular epidemiology during the twenty last years. The mortality from cardiovascular diseases with atherosclerosis as their pathological basis grew rapidly in the industrialised countries after World War II. This led to epidemiological research which started in 1950 with respectively the studies of Framingham in the United States and the Seven Countries Study, essentially in Europe. The concept of multifactorial origin of coronary heart disease was proposed during the 60s. Three major coronary risk factors besides age and gender, hypercholesterolemia, hypertension and cigarette smoking emerged systematically in epidemiological studies before 1975. The last twenty years have confirmed the importance of these three modifiable coronary risk factors which are long-term predictors in different ethnic groups, both in males and females. Other risk factors appeared in this period. Some polymorphisms of several genes as well as their phenotypic expression have been found to be related to an increased risk of coronary heart disease. Uni- and multifactorial primary and secondary prevention trials have confirmed the observations of analytical epidemiology. Moreover, the crucial role of nutrition within a metabolic hypothesis has been confirmed by experimental research. The concept of the strategy of prevention in higher risk subjects as well as in the whole population was proposed by international bodies following the publications by the English epidemiologist G. Rose. Both France and Belgium contributed to the development of cardiovascular epidemiology during the last twenty years. France is doing cutting-edge research on genetic predictors of cardiovascular diseases. Although the multifactorial causal model of cardiovascular diseases is robust, it is still a probabilistic one; it predicts however relative risks of about 15 to 1 according to the decile of the multilogistic function distribution. Environmental factors essentially related to lifestyles explain a great part of these differences. At the individual level, genetic factors most probably modulate these environmental influences and one can foresee in the future a more predictive model. In most medical schools, teaching of cardiovascular epidemiology and prevention has a low priority with clinicians putting the accent on the risk factors rather than on the risk profile of the individual. Secondary prevention is more in the realm of clinical medicine due to a large publicity given to the results of the large randomised trials. Consequently, in hospital mortality of acute myocardial infarction is decreasing as well as long-term mortality. Finally, prevention at the population level is connected to political decisions in public health which could have a major impact on the economy at the country level. Consequently, these political decisions are very slow to be taken both at the national and European Union level.

[Lessons from the MONICA project]

The authors review the various aspects of the MONICA project (Monitoring of Trends and Determinants in Cardiovascular Diseases) coordinated by the World Health Organization. This study comprises, in a defined geographical or administrative entity, an infarction Registry, two or three population surveys and two or three surveys concerning the treatment of the acute phase of myocardial infarction. It is a ten-year study conducted by 39 collaborative centres in 4 continents. The main hypotheses of this study have not yet been verified, as some centres have not completed the 10 years of infarction recording and/or the last population survey. However, the results collected to date and reported in about ten publications grouping all centres, and more than 500 articles published by various centres, demonstrate the wealth of precious information for clinicians provided by this public health project. For example, the infarction Registry demonstrates marked regional differences in myocardial infarction rates in the population and therefore marked differences in acute coronary bed requirements. The Registry also confirms the higher mortality rates in women and at the end of infarction compared to men. Population surveys can be used to follow the course of the main coronary risk factors and to compare the levels of risk factors in different centres. Regional differences clearly show that a more or less aggressive approach to primary prevention is required. Finally, the presence of an infarction Registry and population surveys allow the elaboration of case-control study protocols, several examples of which are mentioned by the authors. All of these techniques will be able to more clearly define the aetiology of coronary heart disease and, consequently, the reduction of this disease in the population by adequate primary and secondary prevention.