Longitudinal Association Between Body Mass Index and Health-Related Quality of Life.

Objective: Health-related quality of life (HRQoL) is an important outcome in individuals with a high risk for cardiovascular diseases. We investigated the association of HRQoL and body mass index (BMI) as an indicator for obesity. Design: Secondary longitudinal analysis of the ORBITAL study, an intervention study which included high-risk cardiovascular primary care patients with hypercholesterolemia and an indication for statin therapy. Methods: HRQoL was determined with the generic Short Form (SF)-12 health status instrument. Body weight and height were assessed at baseline and at months 6, 12, 18, 24, 30, and 36. We used a linear and a linear mixed-effects regression model to investigate the association between BMI and SF-12 summary scores at baseline as well as between change in BMI and SF-12 summary scores over 3 years. We adjusted for age, sex, smoking status, and in the longitudinal analysis also for the study arm and its interaction term with time. Results: Of the 7640 participants who completed the baseline questionnaire, 6726 participants (mean age: 61 years) were analyzed. The baseline BMI was inversely associated with physical and mental SF-12 summary scores (b [95% CI] per 1 kg/ m: 20.36 [20.41; 20.30] and 20.05 [20.11; 20.00], respectively). A significant association between the change in BMI and physical SF-12 summary scores over time was only present in women (20.18 [20.27; 20.09]) and only in obese participants (20.19 [20.29; 20.10]). A change in BMI was directly associated with mental SF-12 summary scores (0.12 [0.06; 0.19]) in the total population. Conclusion: Increases in BMI were associated with decreases in physical HRQoL, particularly in obese individuals and in women. In contrast, the mental HRQoL seemed to increase with increasing BMI over time. Thus, body weight management with respect to the HRQoL should be evaluated differentially by sex and body weight status. Trial Registration: ClinicalTrials.gov NCT00379249 Citation: Muller-Nordhorn J, Muckelbauer R, Englert H, Grittner U, Berger H, et al. (2014) Longitudinal Association between Body Mass Index and Health-Related Quality of Life. PLoS ONE 9(3): e93071. doi:10.1371/journal.pone. 0093071 Editor: Robert L. Newton, Pennington Biomedical Research Center, United States of America Received August 16, 2013; Accepted February 28, 2014; Published March 26, 2014 Copyright: 2014 Muller-Nordhorn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The original intervention study was supported by an unconditional grant from AstraZeneca. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The present analysis was supported exclusively by the Berlin School of Public Health, Charite University Medical Center Berlin. Competing Interests: The original intervention study was supported by an unconditional grant from AstraZeneca. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. * E-mail: jacqueline.mueller-nordhorn@charite.de . These authors contributed equally to this work.