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.