Time trends in body mass index distribution in the general population in Denmark from 1987 to 2021

INTRODUCTION. The epidemic increase in obesity is well documented and of intensive public health interest. Attention has almost entirely focused on a dichotomous measure of obesity such as how the prevalence of BMI >= 30 kg/m(2) has changed over time. Less consideration has been given to how the general distribution of BMI has evolved. METHODS. We used data from the National Health and Morbidity Surveys, which are surveys of the adult Danish population (16 years or above) conducted in 1987, 2000, 2005, 2010, 2013, 2017 and 2021. Participants reported height and weight from which BMI was calculated following correction for systematic bias in self-reported data and non-response. RESULTS. The prevalence of obesity in Denmark increased from 6.1% in 1987 to 18.4% in 2021. A right shift in BMI distribution was observed with positive linear slopes for high and low BMI percentiles and for all socioeconomic groups, although with steeper slopes for high BMI percentiles and for short education. CONCLUSIONS. The right shift in the distribution curve of BMI from 1987 to 2021 with gradually higher values in all BMI percentiles and in all socioeconomic strata show that the increasing obesity prevalence may, to some extent, be attributed to a generally higher BMI in the entire Danish population.