Estimation of Daily Energy Expenditure in Pregnant and Non-Pregnant Women Using a Wrist-Worn Tri-Axial Accelerometer

et al. (2011) Estimation of Daily Energy Expenditure in Pregnant and Non-Pregnant Women Using a Wrist-Worn Tri-Axial Accelerometer. PLoS ONE 6(7): e22922. doi:10.1371/journal.pone.0022922 Estimation of Daily Energy Expenditure in Pregnant and Non-Pregnant Women Using a Wrist-Worn Tri-Axial Accelerometer Vincent T. van Hees 0 Frida Renstro m 0 Antony Wright 0 Anna Gradmark 0 Michael Catt 0 Kong Y. 0 Chen 0 Marie Lo f 0 Les Bluck 0 Jeremy Pomeroy 0 Nicholas J. Wareham 0 Ulf Ekelund 0 Sren Brage 0 Paul W. Franks 0 Jonatan R. Ruiz, University of Granada, Spain 0 1 Medical Research Council Epidemiology Unit, Institute of Metabolic Science , Cambridge , United Kingdom , 2 Genetic Epidemiology and Clinical Research Group, Section for Medicine, Department of Public Health and Clinical Medicine, Umea University Hospital, Umea , Sweden, 3 Genetic and Molecular Epidemiology Unit, Department of Clinical Sciences, Lund University , Malmo , Sweden , 4 Medical Research Council Human Nutrition Research, Cambridge, United Kingdom, 5 Institute for Ageing and Health, Newcastle University , Newcastle , United Kingdom , 6 Clinical Endocrinology Branch , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland, United States of America, 7 Division of Nutrition, Department of Clinical and Experimental Medicine, Linko ping University, Linko ping, Sweden, 8 Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive, and Kidney Diseases, National Institutes of Health , Phoenix, Arizona , United States of America Background: Few studies have compared the validity of objective measures of physical activity energy expenditure (PAEE) in pregnant and non-pregnant women. PAEE is commonly estimated with accelerometers attached to the hip or waist, but little is known about the validity and participant acceptability of wrist attachment. The objectives of the current study were to assess the validity of a simple summary measure derived from a wrist-worn accelerometer (GENEA, Unilever Discover, UK) to estimate PAEE in pregnant and non-pregnant women, and to evaluate participant acceptability. Methods: Non-pregnant (N = 73) and pregnant (N = 35) Swedish women (aged 20-35 yrs) wore the accelerometer on their wrist for 10 days during which total energy expenditure (TEE) was assessed using doubly-labelled water. PAEE was calculated as 0.96TEE-REE. British participants (N = 99; aged 22-65 yrs) wore accelerometers on their non-dominant wrist and hip for seven days and were asked to score the acceptability of monitor placement (scored 1 [least] through 10 [most] acceptable). Results: There was no significant correlation between body weight and PAEE. In non-pregnant women, acceleration explained 24% of the variation in PAEE, which decreased to 19% in leave-one-out cross-validation. In pregnant women, acceleration explained 11% of the variation in PAEE, which was not significant in leave-one-out cross-validation. Median (IQR) acceptability of wrist and hip placement was 9(8-10) and 9(7-10), respectively; there was a within-individual difference of 0.47 (p,.001). Conclusions: A simple summary measure derived from a wrist-worn tri-axial accelerometer adds significantly to the prediction of energy expenditure in non-pregnant women and is scored acceptable by participants. - Funding: This work was supported by Grants from LifeGene (Torsten and Ragnar So derbergs Foundation), Fredrik and Ingrid Thurings Foundation, Umea University Young Investigators Award, and the Vasterbottens regional health authority (all grants to PWF). LifeGene is a charity, by which no commercial interests are involved (https://www.lifegene.se/In-english/). GENEA monitors in the Swedish study were loaned pro gratis from Unilever Discover Ltd. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have the following competing interest: GENEA monitors in the Swedish study were loaned pro gratis from Unilever Discover Ltd. There are no patents, products in development or marketed products to declare. This does not alter the authors adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors. . These authors contributed equally to this work. Glucose metabolism is closely linked to physical activity [1] and maternal glucose homeostasis during pregnancy plays an important role in foetal programming of the endocrine pancreas [2]. However, it is unclear whether higher levels of physical activity during pregnancy are associated with maternal glucose [35], which is partly because the accurate assessment of physical activity in pregnancy is a major challenge. Perhaps because of this, little is known about suitability of objective methods for physical activity assessment which can be used in large-scale studies of pregnant populations [3]. Accelerometers are becoming increasingly popular in epidemiological studies, and because they are relatively non-invasive, they may be suitable for use in a range of settings, including pregnancy. Moreover, accelerometers may provide a more accurate estimation of physical activity-related energy expenditure (PAEE) than can be obtained from more traditional epidemiological approaches, such as questionnaire-based estimations [610]. It is however important that the method used is acceptable to the study participant to minimize selection bias and maximize the amount of data obtained; thus studies that seek to evaluate validity and acceptability of monitors are important. Accelerometers are most commonly attached to the waist using an elastic belt, which, for reasons of discomfort, requires that participants remove the monitor during water-based activities and, generally, also during sleep. This may affect the incompleteness of the data beyond the intended periods of non-wear time because participants forget to re-attach the monitor. Small, waterproof accelerometers allow attachment to the wrist without the need to intermittently remove the monitor, which may improve data completeness. However, accelerometers attached to the wrist may not capture the main body movements that contribute to PAEE as suggested in early laboratory studies comparing uniaxial accelerometry obtained at wrist and waist level [11,12]. However, a recent study reported similar correlations (r.0.8) for triaxial wrist and waist acceleration with energy expenditure during a laboratory simulation of daily activities [13]. The purpose of this study was to examine whether a simple summary measure of tri-axial acceleration from a wrist-worn accelerometer can contribute to estimated PAEE in pregnant and in non-pregnant women. Further, we compared participant acceptability of accelerometers attached to wrist and hip in a different sample, comprising both men and women. Ethics statement Ethical (...truncated)