Quality of life after diet or exercise-induced weight loss in overweight to obese postmenopausal women: The SHAPE-2 randomised controlled trial

Introduction This study investigates the effect of a modest weight loss either by a calorie restricted diet or mainly by increased physical exercise on health related quality of life (HRQoL) in overweight-to-obese and inactive postmenopausal women. We hypothesize that HRQoL improves with weight loss, and that exercise-induced weight loss is more effective for this than diet-induced weight loss. Methods The SHAPE-2 trial was primarily designed to evaluate any additional effect of weight loss by exercise compared with a comparable amount of weight loss by diet on biomarkers relevant for breast cancer risk. In the present analysis we focus on HRQoL. We randomly assigned 243 eligible women to a diet (n = 97), exercise (n = 98), or control group (n = 48). Both interventions aimed for 5–6 kg weight loss. HRQoL was measured at baseline and after 16 weeks by the SF-36 questionnaire. Results Data of 214 women were available for analysis. Weight loss was 4.9 kg (6.1%) and 5.5 kg (6.9%) with diet and exercise, respectively. Scores of the SF-36 domain ‘health change’ increased significantly by 8.8 points (95% CI 1.6;16.1) with diet, and by 20.5 points (95% CI 13.2;27.7) with exercise when compared with control. Direct comparison of diet and exercise showed a statistically significantly stronger improvement with exercise. Both intervention groups showed a tendency towards improvements in most other domains, which were more pronounced in the exercise group, but not statistically different from control or each other. Conclusion In a randomized trial in overweight-to-obese and inactive postmenopausal women a comparable 6%-7% weight loss was achieved by diet-only or mainly by exercise and showed improvements in physical and mental HRQoL domains, but results were not statistically significant in either the diet or exercise group. However, a modest weight loss does lead to a positive change in self-perceived health status. This effect was significantly larger with exercise-induced weight loss than with comparable diet-induced weight loss

Baseline and 16-week differences in HRQoL and intervention effects between study groups.

<p>PCS: Physical Component Summary score (1–5). MCS: Mental Component Summary score (4–8). NOTE 1. As complete cases are presented, i.e., women who filled in a questionnaire both at baseline and follow-up, baseline scores may differ from the baseline scores as presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127520#pone.0127520.t001" target="_blank">Table 1</a>. n = 214 (88.1%) (control group, n = 39; diet group, n = 87; exercise group, n = 88). Analyses were according to the intention-to-treat principle in all complete cases by linear regression with adjustment for the baseline SF-36 domain score. NOTE 2. The eight SF-36 domain scores range from 0 to 100, a higher score on the scale indicates a better health status. The score of the domain ‘<i>health change’</i> ranges from 0 to 100, a score of 50 means no change in perceived health, a score <50 denotes deterioration and >50 improvement. The summary scores PCS and MCS are sex-standardised and represent health scores of the Dutch population with a mean of 50, and a standard deviation (SD) of 10. For example, a PCS score of 60 indicates that physical health is improved with one SD in our study population compared to the general female population.</p><p>Baseline and 16-week differences in HRQoL and intervention effects between study groups.</p

Baseline characteristics of the SHAPE-2 study participants.

<p>PCS: Physical Component Score (1–5). MCS: Mental Component Score (4–8). NOTE 1. Data available for: VO_2peak n = 237 (97.5%); alcohol intake, n = 226 (93.0%); SQUASH physical activity questionnaire, n = 236 (97.1%); ActiGraph accelerometer, n = 161 (out of 215 (74.9%)). For SF-36: domains social functioning, <i>health change</i>, and physical and mental component summary score, n = 229 (94.2%, control group, n = 43; diet group, n = 93; exercise group, n = 93); for physical functioning, role-physical and role-emotional, n = 228 (93.8%); and bodily pain, n = 227 (93.4%). NOTE 2. The eight SF-36 domain scores range from 0 to 100, a higher score on the scale indicates a better health status. The score of the domain ‘<i>health change’</i> ranges from 0 to 100, a score of 50 means no change in perceived health, a score <50 denotes deterioration and >50 improvement. The summary scores PCS and MCS are sex-standardised and represent health scores of the Dutch population with a mean of 50, and a standard deviation (SD) of 10. For example, a PCS score of 60 indicates that physical health is improved with one SD in our study population compared to the general female population.</p><p>* Education, low: primary school and technical/professional school. Middle: college degree. High: university degree</p><p>† GT3X+ ActiGraph activity monitor. Minutes/day of activity spent in each activity category. Activity categories are based on Freedson 1998 cutoff points.</p><p>‡Based on the SQUASH physical activity questionnaire, activities performed ≥4 METs.</p><p>Baseline characteristics of the SHAPE-2 study participants.</p

Association between change in weight (weight loss) and change in HRQoL, regardless of study group.

<p>PCS: Physical Component Score (1–5). MCS: Mental Component Score (4–8).</p><p>*Crude model 1 = Weight loss (i.e. Weight at baseline minus Weight at 16 weeks) = independent, (SF-36 Score at 16 weeks minus SF-36 Score at baseline) = dependent.</p><p>†Adjusted model 2 = model 1 adjusted for intervention group, age, education, baseline SF-36 score and baseline weight</p><p>‡Adjusted model 3 = model 1 adjusted for intervention group, age, education, baseline SF-36 score, baseline weight and change in VO_2peak (mL/min)</p><p>§St-b (with 95% confidence interval, 95%CI) is the regression coefficient from linear regression models that represents the effect on standard deviations (SD) change in HRQoL, per one SD change in weight. E.g., an St-b of 0.16 means that if weight loss increases by 1 SD, the mean SF-36 domain score increases by 0.16 SD.</p><p>Association between change in weight (weight loss) and change in HRQoL, regardless of study group.</p

Association between change in fitness (VO_2peak) and change in HRQoL, regardless of study group.

<p>PCS: Physical Component Score (1–5). MCS: Mental Component Score (4–8).</p><p>*Crude model 1 = (Fitness at 16 weeks minus Fitness at baseline) = independent, (SF-36 Score at 16 weeks minus SF-36 Score at baseline) = dependent.</p><p>†Adjusted model 2 = model 1 adjusted for intervention group, age, education, baseline SF-36 score and baseline VO_2peak (per 10 mL/min)</p><p>‡Adjusted model 3 = model 1 adjusted for intervention group, age, education, baseline SF-36 score, baseline VO_2peak (per 10 mL/min) and change in weight.</p><p>§St-b (with 95% confidence interval, 95%CI) is the regression coefficient from linear regression models that represents the number of standard deviations (SD) change in HRQoL (dependent variable), per 1 SD change in fitness VO_2peak, per 10 mL/min, independent variable). E.g., an St-b of 0.16 means that if fitness increases by 1 SD, the mean SF-36 domain score increases by 0.16 SD.</p><p>Association between change in fitness (VO_2peak) and change in HRQoL, regardless of study group.</p