Biomedical subjects
Publications and source records attributed to G De Backer.
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To study patient compliance in hypertensive outpatients amlodipine (5 mg once daily) and slow release nifedipine (20 mg twice daily) were compared in an open, crossover study in general practices. Four methods of assessment for patient compliance (pill count, taking compliance, days with correct dosing, timing compliance) were used in both study arms. For the latter three assessment a special device, the medication event monitoring system, was used to record the time and date of each opening and closure of the container. The compliance of the 320 hypertensive patients with once-daily amlodipine was markedly superior to twice-daily slow release nifedipine. Therapeutic coverage was also significantly better for amlodipine in the hypertensive patients. Amlodipine was better tolerated than nifedipine slow release. Patient compliance and therapeutic coverage with the calcium antagonist amlodipine given once daily was superior to slow release nifedipine b.d. in hypertensive outpatients recruited in general practice.
Data from 5,817 men and 5,215 women (age range, 25-74 years) who participated in the Belgian Interuniversity Research on Nutrition and Health were used to determine prevalences and associated variables of different abnormalities on the resting electrocardiogram. Electrocardiographic abnormalities were coded according to the Minnesota classification system. About one third of the subjects showed one or more abnormalities on their electrocardiogram. Major abnormalities occurred in 7.3% of the men and in 4.6% of the women. The prevalence of minor abnormalities was twice as high. Minnesota codes 4 (ST abnormalities) and 5 (T wave changes) were found to be the most prevalent in both sexes (9.6 and 10.5% respectively in women and 8.4 and 9.1% respectively in men), while code 2 (QRS axis deviation, 7.9%) and code 7 (ventricular conduction defect, 8.7%) were quite common in men. Most prevalences were rather log-linearly related with age, except codes 6 (atrioventricular conduction defect) and 9 (miscellaneous items). In the asymptomatic subjects, blood pressure showed the strongest positive correlation with minor ST-T abnormalities in both men and women independent of other factors. Other correlates identified by multivariate analyses were serum potassium, serum phosphor, and serum uric acid levels, as well as the intake of diuretics. However, any major, minor, and ST-T abnormalities were, according to sex, differently related to those correlates.
BACKGROUND: The association between fibrinogen and smoking behaviour, age, body mass index, blood pressure, heart rate and plasma lipid profile, was assessed in a cohort of middle-aged working men. METHODS: Seven hundred and forty five subjects were examined as part of a health intervention programme at the work-site. Nine subjects were excluded from the study because of prevalent diabetes. Correlates of plasma fibrinogen concentrations were evaluated through univariate and multivariate methods. RESULTS: In multiple regression analysis fibrinogen correlated with age, smoking behaviour, apolipoprotein B (apo B) apolipoprotein A-I (apo A-I) and lipoprotein (a) (Lp(a)) levels, which together explained 11% of the variation in fibrinogen concentration. From this model, fibrinogen concentration was associated with an increase of 13.6 mg/dl for every 10 years' increase in age, 28.2 mg/dl if a person smoked, and 4.6 mg/dl and 3.8 mg/dl with a 20 mg/dl rise in respectively apo B and Lp(a). A 20 mg/dl increase in apo A-I concentrations was estimated to be associated with a 6.0 mg/dl lower fibrinogen level. CONCLUSION: The data indicate that both biochemical and lifestyle factors are related to the plasma fibrinogen concentration; these interactions may explain partly the relationship between fibrinogen and cardiovascular disease.
Recently, it has been shown that higher plasma serine concentrations are a possible biological marker for psychoses including schizophrenia. The present study was carried out in order to investigate plasma serine levels in 123 depressed subjects (41 minor; 47 simple major; 35 melancholic depressives) and 50 normal controls. It was found that plasma serine concentrations were significantly higher in depressed subjects than in normal controls. There were no significant correlations between plasma serine and postdexamethasone cortisol values. Dexamethasone administration had a significant suppressive effect on plasma serine levels in depression but not in normal controls. In the latter--but not in depressed subjects--there were significant positive correlations between plasma serine and L-tryptophan concentrations.
PURPOSE OF THE STUDY: to evaluate the predictive power of a reduced ankle/brachial pressure index (ABPI) (< or = .90) in an asymptomatic middle-aged male working population free of coronary heart disease. MATERIALS AND METHODS: 2023 subjects forty to fifty-five years old were screened at their work place. Standard techniques were used. Blood was drawn in the fasting state. Ankle and brachial blood pressures were measured by Doppler signals and all measures were done by one observer, duly trained in epidemiologic methodology. RESULTS: in univariate analysis, an ABPI < or = .90 was significantly associated with age, total serum cholesterol, body mass index, smoking, and awareness of diabetes. In multivariate analysis, it was associated with awareness of diabetes, age, Ln triglycerides (P = .073), and smoking (P = .088). Relative risks for reduced versus normal ABPI are 2.77 (P = .010), 4.16 (P = .011) and 4.97 (P = .006) for ten-year all causes, cardiovascular, and coronary mortality, respectively. In a multiple logistic regression analysis, the following variables were significant independent predictors of coronary mortality: smoking (odds ratio [OR] = 4.84), reduced ABPI (OR = 3.63), and low density lipoprotein cholesterol (OR for 1 SD = 1.69). Reduced ABPI is also an independent predictor of cardiovascular mortality. CONCLUSION: a reduced ABPI is an independent risk factor for coronary and cardiovascular mortality in asymptomatic middle-aged Belgian males.
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.
Sudden cardiac death in well-trained athletes is most often superimposed on the presence of structural heart disease. However, some athletes die suddenly in the absence of overt heart disease. To improve identification of athletes at high risk for ventricular tachycardia (VT), ventricular repolarization, the signal-averaged electrocardiogram (ECG), and the echocardiogram from 13 male athletes with symptomatic VT and without evidence of manifest cardiac disease were compared with data obtained in 3 matched control groups (15 apparently healthy professional road cyclists, 10 professional basketball players, and 15 normal control subjects without any sports activity). All patients had apparently normal QRS duration on the routine ECG, and none were taking antiarrhythmic drugs. Echocardiography and signal-averaged electrocardiography were useful in distinguishing the group of athletes with tachyarrhythmias from the group of normal nonsporting controls, but not from both groups of normal athletes. The QT interval (V4) and the QT interval corrected with the cubic root were shorter for the nonsporting controls. Three parameters for QT dispersion showed significant differences (p < 0.003) between athletes with disease and all other groups. It is concluded that although significant differences were detected between normal subjects and the 3 groups of athletes by routine ECG, the signal-averaged ECG, and echocardiography, only an increased QT dispersion from the 12-lead ECG was helpful in distinguishing athletes with VT from other athletes.
BACKGROUND/AIMS: Low serum levels of pepsinogen A are indicative of chronic atrophy, a risk factor for gastric cancer. This study investigated the relationships between low pepsinogen A levels, Helicobacter pylori seropositivity, and gastric cancer rates in 17 populations worldwide. METHODS: In each center, about 200 randomly selected subjects (50 male and 50 female, aged 25-34 and 55-64 years) provided serum samples for pepsinogen analysis and H. pylori serology. RESULTS: Cumulative gastric cancer rates were associated with the prevalence of low pepsinogen A levels in men (coefficient, 0.15 [P = 0.06] for mortality; coefficient, 0.36 [P = 0.01] for incidence) but not women. The prevalence of low pepsinogen A levels was also correlated with H. pylori seropositivity in the older age group (r = 0.55; P = 0.02). Low pepsinogen A levels were significantly more common in the older group (7.5% vs. 2.1% in the younger group; P < 0.001), among women (5.5% vs. 4.1% in men; P = 0.04), and among nonsmokers (5.8% vs. 2.9% in current smokers; P = 0.001). CONCLUSIONS: Low pepsinogen A levels are more common in areas with a high seroprevalence of H. pylori and in men in areas with high rates of gastric cancer. The prevalence of low pepsinogen A levels increases with age, but the excess in women and nonsmokers could reflect factors other than gastric pathology.
The European Atherosclerosis Research Study (EARS) is a study of the biological expression of a paternal history of premature coronary heart disease. The study was carried out in 14 centres in 11 European countries, where the offspring of fathers who suffered a documented myocardial infarction before the age of 55 years (cases) were compared with age- and sex-matched controls. In this paper we describe the measurement of plasma cholesteryl esters as biomarkers for the fatty acid composition of the diet in the cases and controls. No significant differences were found. Cholesteryl palmitate, oleate, linoleate and arachidonate were measured in plasma and correlated with plasma lipids and lipoproteins and with life-style variables including body-mass index, alcohol consumption, tobacco and physical activity. The strongest correlations were observed between cholesteryl esters and triglycerides, which are positively correlated with cholesteryl oleate and negatively with cholesteryl linoleate. Apo B was negatively correlated with cholesteryl linoleate and positively with palmitate. Among the other variables, alcohol was positively correlated with cholesteryl oleate and negatively with linoleate, both in males and in females. Furthermore, there are differences between regions, with the highest percentages of saturated cholesteryl palmitate measured in Finnish students, the highest percentage of cholesteryl linoleate in Belgium and of cholesteryl arachidonate in Southern Europe.
To study the association between serum calcium and serum lipids, data from 5394 men and 4800 women in the Belgian Interuniversity Research on Nutrition and Health (25-74 years) were used. By visual inspection of the data a linear increase of both total and HDL cholesterol with serum calcium levels was observed, consistently over all age groups and both sexes. In order to adjust the measured serum calcium concentrations for total serum protein, statistical analyses were performed using Parfitt's correction formula. Multivariate analysis showed in both sexes a highly significant positive association between corrected calcium and total cholesterol independent of age, systolic blood pressure, body mass index, serum uric acid, P/S ratio of diet, cholesterol intake, smoking, educational level and geographical area. The adjusted differences in total cholesterol between the lowest and highest quartile range of the calcium distribution were about 13 mg/dl for both men and women. Protein-corrected calcium was among the strongest correlates with total cholesterol. The analysis of the relation with HDL cholesterol revealed an effect modification by gender. For men no statistically significant correlation between calcium and HDL cholesterol was observed while for women a strong increase of HDL with protein-corrected calcium was found resulting in an adjusted difference of 2.5 mg/dl between the lowest and highest calcium quartile range.
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Return to work was studied in all men who had entered the infarct register in the city of Ghent between 1983 and 1988 because of a first myocardial infarction before the age of 60 years. Information on work resumption was collected in 1991 using a postal survey; 78% of the 295 eligible subjects participated. Sixty-nine percent of all responders and 85% of all those who were at work before the infarct returned to work. Age, the perceived importance of the job, support from friends and the participation in a comprehensive cardiac rehabilitation programme were significantly related to work resumption.
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The relationship between ECG abnormalities and mortality was studied in 4797 males and 4320 females aged 25 to 74 years who took part in the Belgian Inter-university Research on Nutrition and Health (The BIRNH study). At entry all were free of angina, had no history of acute myocardial infarction and showed no evidence of an old infarction on their baseline ECG. They were followed for an average of 5.6 years, and follow-up for vital status was completed satisfactorily in 99.5%. ECG abnormalities were grouped using several classifications: any abnormality, major and minor abnormalities, ischaemic changes, left ventricular hypertrophy and the separate Minnesota codes IV (ST depression), V (abnormal T-wave) and VIII (arrhythmias). Using logistic regression analysis, adjustment of odds ratios for cardiovascular disease (CVD) mortality was done for age, systolic blood pressure, serum total cholesterol and uric acid, diabetes, smoking and antihypertensive drug treatment. Men outnumbered women more than twice in total and CVD mortality. Multivariate analysis showed that the presence of major abnormalities on the ECG was significantly related to CVD mortality in both men and women (adjusted odds ratios 2.73 and 4.40 respectively). In contrast, minor abnormalities were not independently associated with CVD mortality. In men, ST depression (OR = 5.58), signs of an ischaemic ECG (OR = 3.02) and an abnormal T-wave (OR = 2.58) were independently related to CVD mortality. In women primarily a ST depression (OR = 5.87) and arrhythmias (OR = 4.22) had a significant independent effect on CVD mortality.(ABSTRACT TRUNCATED AT 250 WORDS)
The European Atherosclerosis Research Study (EARS) is a multicenter collaborative project within the European community. Its main objective is to study in young individuals the biological expression of a paternal history of premature coronary heart disease and to analyze the relative contribution of genetic and environmental factors to this expression. This study was carried out in 14 centers in 11 European countries, where the offspring of fathers who suffered a documented myocardial infarction before the age of 55 years (cases) were compared with age- and sex-matched control subjects. Plasma apolipoproteins A-I, B, A-II, A-IV, and E and lipoprotein (Lp) A-I lipoparticles were measured in this student population. Comparison of the values between cases and control subjects showed significantly higher apo B levels in cases compared with control subjects, and these differences were homogeneous throughout Europe. Regional differences were observed for apo E levels with an increasing north-south gradient, which was inversely related to that observed for triglycerides. A stepwise regression analysis including the lipid and apolipoprotein variables showed that apo B and triglycerides were the strongest discriminators between offspring of fathers with premature coronary heart disease and control subjects.
In 17 patients who returned to work following rehabilitation after an uncomplicated acute myocardial infarction (AMI), the myocardial oxygen demands (MOD) of various job activities were assessed using discontinuous ambulatory heart rate (HR) and blood pressure measurements. All patients were on beta-blocking agents. HR and rate-pressure product (RPP) reserves were calculated as the differences between maximal values observed during a symptom-limited maximal bicycle exercise test and basal values. Basal values were either pre-test resting values or mean values from night-time registrations between 0100h and 0500h. Night-time values of basal HR and RPP were 7.7 and 18.7% lower respectively as compared to pre-test resting values. The myocardial energy demands of various job activities were calculated as the percentage use of the reserves. This resulted in lower MOD estimations when pre-test values were used as compared to night-time values. These differences were larger for the estimation of MOD of light physical work (mean difference 25%) than for heavy physical work (mean difference 12%). The estimations of MOD using HR reserve or RPP reserve were very similar. In patients who performed the same job activities no correlation was found between MOD and left ventricle ejection fraction. We believe these data provide useful information about the functional capacity of AMI patients. They also emphasise the great importance that has to be attached to the definition of basal values.
In an extensive health survey 115 male viscose rayon workers exposed to carbon disulphide (CS2) and 76 referents not exposed to this chemical were interviewed using the WHO cardiovascular questionnaire and responded to a self-administered questionnaire. A 12-lead ECG was taken and coded using the Minnesota code. Blood pressure (BP) was measured electronically and blood was examined for lipoproteins. In the viscose rayon factory the working conditions had not changed since 1932. Personal monitoring performed in 17 jobs, showed exposures varying from 4 to 112 mg/m3. For each individual a CS2 cumulative exposure index (CS2 index) was calculated. There were no significant differences between exposed and referents concerning the prevalence of angina, history of myocardial infarction, intermittent claudication and ECG signs of ischaemia. Blood pressure, low density lipoprotein (LDL)-cholesterol and the apolipoproteins A1 and B rose while high density lipoprotein (HDL)-cholesterol, the HDL-cholesterol/apolipoprotein A1 and the LDL-cholesterol/apolipoprotein B ratios decreased significantly with increasing exposure. Adjustment for age, body mass index, smoking, alcohol consumption, stress and tension at work, shift work, noise exposure and educational level in multiple linear regression analysis showed significant effects of the CS2 index on systolic BP, diastolic BP, cholesterol, HDL-cholesterol, LDL-cholesterol, apolipoprotein A1, apolipoprotein B, the LDL cholesterol/apolipoprotein B and HDL cholesterol/apolipoprotein A1 ratios; there were no significant effects on the triglycerides.