The burden of obesity in Norway: morbidity, mortality, health service use and productivity loss

Obesity levels have escalated dramatically the past 30 years. Nevertheless, little is known about the burden of obesity in Norway, and the identification of causal patterns is complex due to the multidimensional concept of obesity. We used the rich and unique infrastructure for health data research in Norway along with improved statistical methods to provide comprehensive estimates of the burden of obesity in Norway. Linking national register data to large scale population studies that contain obesity measures and genetic markers provided a novel research opportunity. As we used genetic markers in instrumental variable analyses, we estimated potential causal effects by avoiding residual confounding and reverse causality. The aim of our project was to study the impact of obesity on morbidity, mortality, health service use and social insurance benefits in Norway. To achieve this, we assembled an interdisciplinary team in genetic epidemiology and health economics. The project has employed one PostDoc and one PhD-student. The project participants have contributed to a number of papers published in peer-reviewed journals on the topic. They have also attended scientific conferences and the findings have gotten media attention. Our results will be important to inform future health policies and obesity prevention strategies. The PhD-student has successfully defended her thesis for the degree of PhD. We found that increased overweight and obesity are likely to lead to increased pressure on the health service. But the effects were somewhat smaller than previous studies have shown. Furthermore, we found that an increased body mass index reduced the income of women, but no effect was found in men. Some analysis was also done on the validity of our analysis strategy. We could not definitively conclude that the use of genes in instrument variable models is a valid way to calculate causal effects of overweight and obesity on different outcomes.

- En stipendiat har disputert. - Flere vitenskapelige artikler har blitt publisert - Flere foredrag er holdt på vitenskapelige konferanser - På lengre sikt vil disse resultatene kunne benyttes direkte til beslutningstagning om tiltak rettet mot overvekt og fedme. I tillegg vil resultatene kunne brukes indirekte i nytte-kostnadsanalyser

Obesity levels have escalated dramatically the past 30 years resulting in increased disease burden and major cost consequences. Nevertheless, little is known about the burden of obesity in Norway, and the identification of causal patterns is complex due to the multidimensional concept of obesity. We will use the rich and unique infrastructure for health data research in Norway along with improved statistical methods to provide comprehensive and valid estimates of the burden of obesity in Norway. Linking national register data to large scale population studies that contain obesity measures and genetic markers provides an exceptional research opportunity in a global perspective. Furthermore, applying genetic markers in instrumental variable analyses may advance causal inference by avoiding residual confounding and reverse causality. The aim of our project is to study the impact of obesity on morbidity, mortality, health service use and social insurance benefits in Norway. Two sets of analyses will be conducted. Firstly, we aim to gain an understanding of the total burden of obesity in Norway by estimating individual trajectories and cost of illness by different demographic and social characteristics. Secondly, we aim to assess the causal impact of obesity on health and health service use by the use of genetic markers as natural experiments. To achieve this we have assembled an interdisciplinary team of complementary strength, primarily from two institutions in Norway consisting of genetic epidemiology and health economics. Our results will be important to inform future health policies and obesity prevention strategies.