Mean BMI of the Belgians entering the dangerous zone

Sabine Drieskens, Scientific Institute of Public Health
Johan Van der Heyden, Scientific Institute of Public Health
Stefaan Demarest, Scientific Institute of Public Health
Jean Tafforeau, Scientific Institute of Public Health

Background: The Body Mass Index (BMI) is an indication of the health status of a population. Research has shown that a BMI of 25 or more (cut-off point for overweight) increases the risk of morbidity (diabetes, cardiovascular diseases, some cancers) and mortality. The distribution of BMI is shifting upwards in many countries. One of the targets of the World Health Organization is preventing and managing the global epidemic of obesity. Data and Methods: Cross-sectional data from four successive waves (1997, 2001, 2004 and 2008) of the Belgian Health Interview Survey (HIS) were analysed. Since the BMI, calculated as weight (kg)/square length (m²), is stable from 18 years on, the study is restricted to the adult population (18+ years), resulting in a sample of respectively 8075, 9400, 10331 and 8837 individuals. Linear regression was used to assess the evolution for the mean BMI after adjustment for age and/or gender; logistic regression for the evolution of the proportion of people with overweight. Results: A significant linear increase of the mean BMI is observed among the Belgian adult population: from 24,7 in 1997, to 25,0 in 2001, 25,1 in 2004 until 25,3 in 2008 (P < 0,05). The average Belgian is thus too thick since 2001! The mean BMI of men (25,7 in 2008) is higher than the one for women (24,8 in 2008). More and more people suffer from overweight: from 41% in 1997, to 44% in 2001 and 2004 until 47% in 2008, which is also a significant increasing trend (P < 0,05). Conclusions: It is not obvious for policy makers to qualify overweight as a public health priority while most of the people don’t experience it as a health threat. But when nearly half of the population is overweight it is imperative to place this problem high on the agenda.