M. Dramaix

Sociodemographic and nutritional determinants of obesity in Belgium.

OBJECTIVE: To examine associations between sociodemographic, dietary factors and physical activity and the prevalence of obesity in the Belgian general population.DESIGN: Base-line data from the Belgian Interuniversity Research on Nutrition and Health (BIRNH) study (1979–1984).SUBJECTS: A total of 5837 men and 5243 women aged 25–74 y were included in the analysis. The sample was considered representative of the Belgian population.MEASUREMENTS: Using the body mass index (BMI) as the criterion, obesity was defined as a BMI≥30 kg/m2. Nutritional data were assessed by a 24 h food record. Physical activity level (PAL) was calculated by dividing total caloric intake by an estimation of basal metabolic rate (BMR, predicted from gender, weight and age). Age-adjusted odds ratios (OR) of the prevalence of obesity were estimated by multilogistic regression analysis.RESULTS: Prevalence of obesity was 12.1% in men and 18.4% in women. In both sexes, prevalence of obesity increased gradually in each 10-year age category (P<0.0001) and steeply decreased with level of education. Comparing lowest (Q1) to highest quartile (Q4), after adjustment for age, prevalence of obesity decreased with total carbohydrate intake, as well as total sugar intake in both sexes, and increased with total fat intake only in men. Obesity increased with a high fat to sugar ratio (men: ORQ4/Q1=1.56; confidence interval (CI): 1.25–1.93; women: ORQ4/Q1=1.45; CI: 1.17–1.80). PAL was inversely and very strongly associated with obesity (men: ORQ4/Q1=0.20; CI: 0.15–0.26; women: ORQ4/Q1=0.18; CI: 0.14–0.23). The same associations were observed with the mean BMI.CONCLUSION: This study indicates that prevalence of obesity is particularly high in Belgium. Low level of education and reduced physical activity, increased fat intake and especially elevated fat to sugar ratio appear to be powerful determinants of obesity in this Belgian population.

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.

Psycho-socio-biological correlates of moderate overweight in an industrial population

Abstract This paper deals with the study of the relation between psycho-socio-biological factors and moderate overweight of subjects participating to the Belgian Heart Disease Prevention Project. The 8284 male subjects of the trial, working in 30 Belgian Flemish or French-speaking factories, aged 40–59 yr, were medically screened and asked to answer medical, social and psychological questionnaires. Base-line data are here analysed in regard to relative weight (mean relative weight and tertiles of relative weight). Stepwise discriminant analyses between tertile III and tertile I introducing psychological, social and bioclinical variables, showed that the ‘obese’ subjects (tertile III) are less frequently cigarette smokers, are less neurotic, are of a lower occupational class, are more frequently living in Wallonia (south of Belgium) and are more extravert compared to the ‘lean’ subjects (tertile I). Moreover, prospective studies are further needed to determine the causal or sequential effects on moderate overweight of the two psychological factors: neuroticism and extraversion.

The influence of socioeconomic status on the incidence and evolution of obesity during early adolescence

OBJECT: To analyze the influence of socioeconomic status on the prevalence, evolution and incidence of obesity between the ages of 12 y and 15 y in Belgium.DESIGN: Retrospective cohort study.SUBJECTS: 2607 children from five social groups.MEASUREMENTS: The body mass index (BMI) measured during two school medical examinations carried out at an interval of two years between the ages of 12 y and 15 y.RESULTS: Between the ages of 12 y and 15 y the inverse relation between social status and the prevalence of obesity is accentuated in girls. The increasing divergence between social groups was a result both of the greater incidence of new cases of obesity and the reduced improvement rate in obesity already present in adolescents of lower social classes.CONCLUSIONS: Social inequalities in obesity increase during early adolescence. Preventive measures, targeting children of low socioeconomic status, should be put in place at this stage of life.

Physical Activity and Physical Fitness Levels of Belgian Males Aged 40-55 Years

Physical activity during leisure time and on the job have been measured with standardized interview techniques in 1,513 normal men, aged 40-55 years, who were regularly employed in different industries. Physical fitness was simultaneously estimated by measuring the work load at which a heart rate of 150 bpm was reached on a standardized exercise test. The median energy expenditure from leisure time activities above the basal metabolic rate was 195 kcal/day; 19% of these activities were classified as heavy, 37% as moderate and 43% as light intensity. The median energy expenditure from job physical activity was 1,676 kcal/day including basal metabolic rate. The median physical fitness level was 125 W. The leisure time activity score was significantly related to physical fitness through the light and the heavy intensity subscores. Independently, job physical activity was also significantly related to physical fitness. However, both activity scores accounted for only 2% of the variance in physical fitness. The data illustrate an overall low energy expenditure profile of middle-aged normal men and a low order relationship between physical activity pattern and physical fitness.

The Belgian heart disease prevention project. Modification of the coronary risk profile in an industrial population.

The Belgian Heart Disease Prevention Project is a controlled, multifactorial prevention trial involving 19,390 males aged 40–59 years employed by 30 Belgian industries. These industries were paired and randomized into a control or intervention unit. In each intervention factory, the subjects from the two highest deciles of a coronary risk-score distribution curve were given individual advice twice a year. A health education campaign was also organized in each intervention factory. In the control group, 10% of randomly chosen subjects had the same baseline examination as the whole of the intervention group. After 2 years, high-risk subjects and random samples of the control and intervention group were compared regarding the coronary risk profile by means of a multiple logistic function (MLF). In the intervention high-risk group, the MLF showed a decrease of 20%, and in the control group there was an increment of 12.5% (p < 0.001). Comparing the random samples an increment of 25% was found in the control group vs a drop of 2.26 in the intervention group (p < 0.001). The coronary risk profile can be altered in a middle-aged male working population through mass media health education supplemented by face-to-face counseling in high-risk subjects.

Serum lipids and apoproteins in students whose parents suffered prematurely from a myocardial infarction

Lipids and apoproteins as well as other coronary risk factors were measured in offspring of patients who suffered from a myocardial infarction before the age of 50 years; the results are compared with the results of a control group matched for age and sex. Significant differences were observed in the apoprotein A1 level, in the protein/fat ratios of high- and low-density lipoproteins, and in smoking habits. In a multivariate analysis, the offspring group was found to be different from the control group in nonhigh-density lipoprotein cholesterol/apoprotein B ratio, high-density lipoprotein cholesterol/apoprotein A1 ratio, smoking habits, apoprotein A1, and apoprotein A2. By means of these variables a total of 85% of all subjects could be correctly classified. We conclude that as early as age 21 years the offspring of patients with premature coronary heart disease differ from matched control subjects in lipoprotein measurements and in smoking habits.

The Belgian Heart Disease Prevention Project: type "A" behavior pattern and the prevalence of coronary heart disease.

&NA; A relation between the Type A behavior pattern and the prevalence of coronary heart disease (CHD), independent of other coronary risk factors, was demonstrated in the Belgian Heart Disease Prevention Project. The association was strongest with angina pectoris or with electrocardiogram (ECG) abnormalities in subjects with known CHD; however, particular aspects of the Type A behavior pattern dealing with time urgency were also related to ECG abnormalities in patients with no angina pectoris and no history of CHD.

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.

Behavior, stress, and psychosocial traits as risk factors

Although psychosocial factors have long been associated with the pathogenesis of heart disease, the independent relation between these variables and coronary heart disease (CHD) is still controversial. However, when experimental, clinical pathological, and epidemiologic studies are taken together, strong evidence is provided that psychosocial and behavioral factors are important in the development and the provocation of clinical CHD manifestations. Heterogeneity in study results is partially due to methodological problems in defining and measuring behavior, stress, and psychosocial traits in population groups as well as in individuals. The difficulties in separating the role of psychosocial factors from the classic risk factors strengthen the importance and need for these factors to be considered in the design of further clinical and epidemiologic studies, not only to explore their independent predictive value but also to study their role in adherence to preventive advice and in the reversibility of risk. In these respects results are presented from a prospective epidemiologic and from a controlled multifactorial intervention study.