Rutters F.,Maastricht University |
Gerver W.J.,Maastricht Academic Medical Center |
Nieuwenhuizen A.G.,Maastricht University |
Verhoef S.P.M.,Maastricht University |
Westerterp-Plantenga M.S.,Maastricht University
International Journal of Obesity | Year: 2010
Background:Short sleep duration is associated with obesity during childhood and adulthood.Objective:The objective of our study was to investigate the relationship between sleep duration and body mass index (BMI) from Tanner stages 1 to 5 in a Dutch children cohort.Design:In 98 children, anthropometric measurements and leptin concentrations were measured from age 7 to 16 years; body composition, physical activity (Baecke questionnaire), hours television viewing and self-reported sleep duration were measured yearly from age 12 to 16 years. Moreover, the polymorphisms of the FTO gene (rs9939609) and parental BMI's were determined.Results:At Tanner stages 1-5 sex differences were observed in height, body weight, waist circumference, fat mass per squared meter height and leptin concentrations per kg fat mass. Inverse relationships were observed between the change in BMI (kg m -2) and the change in hours of sleep per night (h) from Tanner stages 1 to 4 (r=-0.68, P<0.001), from Tanner stages 2 to 5 (r=-0.35, P<0.05) and from Tanner stages 1 to 5 (r=-0.33, P<0.05). Univariate analysis of variance showed that with progressive Tanner stages, BMI increases and sleep duration decreases in an interrelated way independent of possible confounders (R 2=0.38, P<0.02).Conclusion: Changes in BMI during puberty were inversely related to changes in sleep duration, independent of possible confounders. © 2010 Macmillan Publishers Limited All rights reserved.
Rutten E.P.A.,Maastricht Academic Medical Center |
Wouters E.F.M.,Maastricht Academic Medical Center
Respiratory Medicine | Year: 2010
Background: Assessment of muscle wasting in COPD is relevant as it is independently associated with metabolic and functional consequences and even survival. Muscle wasting can be approached by assessing fat free mass (FFM), but it is already demonstrated that FFM measured by bio-electrical impedance analysis (BIA) underestimates FFM measured by dual energy X-ray absorptiometry (FFMDExA) in a relatively small COPD group. Objective: To evaluated critical points for defining muscle wasting in a large cohort of moderate to severe COPD patients and with DEXA scan as reference. Design: FFM by BIA was compared with FFMDExA in 1087 COPD patients (641♂, FEV1: 44.8 ± 17.5%pred). In a subgroup (n = 422), FFMDExA was predicted by multivariate analysis and a new formula to calculate FFM by BIA was developed. The new formula was compared with FFMDExA in the remaining subgroup (n = 665). Muscle wasting was defined according to the cut-offs of Schols et al. (FFM index (FFMI)<16 kg/m2 for men, 15 kg/m2 for women), Vestbo et al. (FFMI < 17.1 kg/m2 for men, 14.6 kg/m2 for women), and Coin et al. (FFMI < 17.8 kg/m2 for men, 14.6 kg/m2 for women). Results: There was an underestimation of FFM by BIA when compared to FFMDExA by the Bland Altman. Comparing the new formula with FFMDExA, the mean underestimation almost disappeared but the variation remained. The proportion of muscle wasting was largely dependent on the used cut-offs, especially in men. Conclusion: The results of the present study emphasize the importance to accurately bare in mind the technique and cut-offs to establish muscle wasting before implementing it in the clinical practice. Crown Copyright © 2009.