Background: During the last two decades, obesity has reached epidemic proportions in industrialised societies such as Sweden.
Objective: The first aim of this study is to examine whether the body mass index (BMI) and obesity increased between 1996/97 and 2000/01 in different subgroups in the Swedish population. The second aim is to examine whether there were any differences in BMI between subgroups of the population, characterised by age, gender, educational status, smoking habits, degree of urbanisation, and country of birth. The third aim is to examine whether BMI increased between the two periods after adjustment for all the explanatory variables.
Methods: This study is based on two cross-sectional, random samples of the entire population aged 16-84 y, the first from 1996/97 including 5622 men and 5940 women and the second from 2000/01 including 5515 men and 5838 women. To investigate the possible change in obesity between the two periods, a logistic model adjusted for age was applied, after stratification by gender. To study the relationship between BMI and the explanatory variables, and the possible change in the subgroups of the population between the two periods, a linear regression model was used.
Results: The total BMI mean increased by 0.4 units from 1996/97 to 2000/01 for both men and women. The prevalence of obesity also increased to about 10% in 2000/01. In some subgroups, the prevalence of obesity was especially high, for example, men and women aged 55-74 y, men with middle educational status, women with low educational status, former smokers, and Finnish-born men and women.
Conclusions: These findings illustrate that both BMI and obesity increased in the Swedish population between 1996/97 and 2000/01. This increase in BMI and obesity is most likely due to environmental factors, such as diet and a sedentary lifestyle. Health interventions need to target both certain subgroups and the whole population.