Causes and Consequences of Body Fat Changes Across the Adult Life Span

Today is adults (independent of age) recommended to maintain a normal BMI (18.5-24.9 kg/m2). This is problematic, since older persons in a BMI category might have very different weight histories. For example, some might have gained weight late in life, while others might have been obese in midlife but lost weight in late life. Existing longitudinal population-based studies that originate from the Swedish Twin Registry (SATSA n=859, OCTO-Twin n=702, and Gender n=498, and) containing data ranging more than 65 years and including 1941 persons with at least one assessment of BMI (n=1247, 3 or more assessments) will be used. Apart from BMI we also have repeated measures of other body fat (BF) indices, such as waist circumference and hip circumference. In SATSA, leukocyte DNA methylation is available for 368 persons with up to five assessments. We have also identified 30 monozygotic (MZ) twin pairs who either are discordant for BMI level (6 pairs), have different BMI trajectories (11 pairs), or both (13 pairs) of which we have 3-5 methylation data points. Additional analyses will be performed on TwinGene n=10,904, LifeGene n=25,000 and EpiHealth n=21,000. By using a within-person approach, we will identify specific body fat (BF) trajectories that exist in the population, i.e. clusters of individuals will be created based on the individuals’ BF trajectories. We will examine how different BF trajectories relates to diseases common in late life, and survival. When specific BF trajectories are related to disease and survival we will focus on risk factors of belonging to these negative BF trajectories. A special strength is that we have access to repeated measures (up to five times over 20 years) of leukocyte DNA methylation in combination with other biomarkers and genotypes from both monozygotic (MZ) and dizygotic (DZ) twins. Underlying causes of BF changes such as genetics and epigenetics but also environmental factors will be analyzed with longitudinal models and twin methods. The current project will contribute with general knowledge about the causes and consequences of obesity and BF changes across the adult life course.

Contakt: Anna Dahl Aslan