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AIM: Feeding of preterm-born children has been extensively studied during infancy. Few studies have focused on later life but the available data indicate that feeding problems may persist after infancy. We studied this topic using two cohorts of full-term and preterm-born children. METHODS: The Children's Eating Difficulties Questionnaire was used to assess the appetite, food enjoyment, pickiness and neophobia, the fear of new foods, of 347 four-year-old children born in 2009-2011. Of these, 179 (52% boys) were born preterm at 24 to 36 weeks and recruited from paediatric clinics in southeast Sweden. The 168 children (54% boys) born full-term were recruited from a maternity health clinic in the same region. The parents graded 12 statements about their child's eating behaviour from very false to very true. RESULTS: A low gestational age at birth was associated with less reported appetite in girls. Estimates describing appetite and food enjoyment correlated with gestational age at birth in girls but not in boys. This difference between boys and girls was significant (p < 0.05). CONCLUSION: Prematurity had no major effects on food-related behaviour in four-year-old children. However, some estimates of reduced appetite and food enjoyment were associated with lower gestational age at birth in girls but not in boys.
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Trastornos de Alimentación y de la Ingestión de Alimentos , Nacimiento Prematuro , Niño , Masculino , Recién Nacido , Femenino , Humanos , Embarazo , Adolescente , Preescolar , Conducta Alimentaria , Encuestas y Cuestionarios , Edad GestacionalRESUMEN
BACKGROUND: Birth weight is determined by the interplay between infant genetics and the intrauterine environment and is associated with several health outcomes in later life. Many studies have reported an association between birth weight and DNA methylation in infants and suggest that altered epigenetics may underlie birthweight-associated health outcomes. However, birth weight is a relatively nonspecific measure of fetal growth and consists of fat mass and fat-free mass which may have different effects on health outcomes which motivates studies of infant body composition and DNA methylation. Here, we combined genome-wide DNA methylation profiling of buccal cells from 47 full-term one-week old infants with accurate measurements of infant fat mass and fat-free mass using air-displacement plethysmography. RESULTS: No significant association was found between DNA methylation in infant buccal cells and infant body composition. Moreover, no association between infant DNA methylation and parental body composition or indicators of maternal glucose metabolism were found. CONCLUSIONS: Despite accurate measures of body composition, we did not identify any associations between infant body fatness and DNA methylation. These results are consistent with recent studies that generally have identified only weak associations between DNA methylation and birthweight. Although our results should be confirmed by additional larger studies, our findings may suggest that differences in DNA methylation between individuals with low and high body fatness may be established later in childhood.
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Metilación de ADN , Mucosa Bucal , Tejido Adiposo , Peso al Nacer/genética , Composición Corporal/genética , Índice de Masa Corporal , Humanos , LactanteRESUMEN
AIM: Premature birth is a worldwide problem and increases the risk of chronic disease later in life. Prematurely born infants may have a high percentage of body fat at term-equivalent age, but it is unclear if this characteristic is maintained in childhood. Therefore, we compared the size and body composition of four-year-old prematurely born children to such values of full-term controls. METHODS: Between 2013 and 2015, we assessed weight, height, fat mass and fat-free mass, using air displacement plethysmography in 188 reasonably healthy prematurely born four-year-olds (98 boys). RESULTS: At four years of age, prematurely born children (gestational weeks at birth: 23.3-36.9) tended to be lighter and shorter and to contain less fat mass and fat-free mass than did full-term controls. The gestational age at birth of the prematurely born children correlated positively and significantly (P < .05) with height, weight, body mass index, fat mass (kg, %), fat mass index and fat-free mass (kg) in girls but not in boys. CONCLUSION: Prematurity was not associated with increased body fatness in our four-year-olds. Our findings are relevant in relation to previously published results showing that premature birth is associated with chronic disease later in life.
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Nacimiento Prematuro , Tejido Adiposo , Peso al Nacer , Composición Corporal , Índice de Masa Corporal , Peso Corporal , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Pletismografía , Embarazo , Nacimiento Prematuro/epidemiologíaRESUMEN
BACKGROUND: Physical activity is associated with health in women. Published MET-values (MET: metabolic equivalent of task) may assess physical activity and energy expenditure but tend to be too low for subjects with a high total body fat (TBF) content and therefore inappropriate for many contemporary women. The MET-value for an activity is the energy expenditure of a subject performing this activity divided by his/her resting energy expenditure, often assumed to be 4.2 kJ/kg/h. Relationships between TBF and MET have been little studied although overweight and obesity is common in women. Available data indicate that MET-values decrease during pregnancy but more studies in pregnant contemporary women are needed. SUBJECTS AND METHODS: Using indirect calorimetry we measured energy expenditure and assessed MET-values in women, 22 non-pregnant (BMI: 18-34) and 22 in gestational week 32 (non-pregnant BMI: 18-32) when resting, sitting, cycling (30 and 60 watts), walking (3.2 and 5.6 km/h) and running (8 km/h). Relationships between TBF and MET-values were investigated and used to predict modified MET-values. The potential of such values to improve calculations of total energy expenditure of women was investigated. RESULTS: The resting energy expenditure was below 4.2 kJ/kg/h in both groups of women. Women in gestational week 32 had a higher resting energy metabolism (p < 0.001) and 7-15% lower MET-values (p < 0.05) than non-pregnant women. MET-values of all activities were correlated with TBF (p < 0.05) in non-pregnant women and modified MET-values improved estimates of total energy expenditure in such women. In pregnant women, correlations (p ≤ 0.03) between TBF and MET were found for running (8 km/h) and for walking at 5.6 km/h. CONCLUSIONS: Our results are relevant when attempts are made to modify the MET-system in contemporary pregnant and non-pregnant women. MET-values were decreased in gestational week 32, mainly due to an increased resting energy metabolism and studies describing how body composition affects the one MET-value (i.e. the resting energy metabolism in kJ/kg/h) during pregnancy are warranted. Studies of how pregnancy and TBF affect MET-values of high intensity activities are also needed. Corrections based on TBF may have a potential to improve the MET-system in non-pregnant women.
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Nutritional epidemiology is an inherently complex and multifaceted research area. Dietary intake is a complex exposure and is challenging to describe and assess, and links between diet, health, and disease are difficult to ascertain. Consequently, adequate reporting is necessary to facilitate comprehension, interpretation, and generalizability of results and conclusions. The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement is an international and collaborative initiative aiming to enhance the quality of reporting of observational studies. We previously presented a checklist of 24 reporting recommendations for the field of nutritional epidemiology, called "the STROBE-nut." The STROBE-nut is an extension of the general STROBE statement, intended to complement the STROBE recommendations to improve and standardize the reporting in nutritional epidemiology. The aim of the present article is to explain the rationale for, and elaborate on, the STROBE-nut recommendations to enhance the clarity and to facilitate the understanding of the guidelines. Examples from the published literature are used as illustrations, and references are provided for further reading.
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Dieta , Evaluación Nutricional , Estudios Observacionales como Asunto , Lista de Verificación , Diseño de Investigaciones Epidemiológicas , Ejercicio Físico , Calidad de los Alimentos , Humanos , Ingesta Diaria Recomendada , Reproducibilidad de los Resultados , Proyectos de Investigación , Informe de Investigación , Encuestas y CuestionariosRESUMEN
BACKGROUND: Concerns have been raised about the quality of reporting in nutritional epidemiology. Research reporting guidelines such as the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement can improve quality of reporting in observational studies. Herein, we propose recommendations for reporting nutritional epidemiology and dietary assessment research by extending the STROBE statement into Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut). METHODS AND FINDINGS: Recommendations for the reporting of nutritional epidemiology and dietary assessment research were developed following a systematic and consultative process, coordinated by a multidisciplinary group of 21 experts. Consensus on reporting guidelines was reached through a three-round Delphi consultation process with 53 external experts. In total, 24 recommendations for nutritional epidemiology were added to the STROBE checklist. CONCLUSION: When used appropriately, reporting guidelines for nutritional epidemiology can contribute to improve reporting of observational studies with a focus on diet and health.
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Diseño de Investigaciones Epidemiológicas , Ciencias de la Nutrición/métodos , Estudios Observacionales como Asunto/normas , Informe de Investigación/normas , Lista de Verificación , Guías como Asunto/normas , Humanos , Ciencias de la Nutrición/normasRESUMEN
(1) BACKGROUND: Assessing the quality of growth in premature infants is important in order to be able to provide them with optimal nutrition. The Pea Pod device, based on air displacement plethysmography, is able to assess body composition of infants. However, this method has not been sufficiently evaluated in premature infants; (2) METHODS: In 14 infants in an age range of 3-7 days, born after 32-35 completed weeks of gestation, body weight, body volume, fat-free mass density (predicted by the Pea Pod software), and total body water (isotope dilution) were assessed. Reference estimates of fat-free mass density and body composition were obtained using a three-component model; (3) RESULTS: Fat-free mass density values, predicted using Pea Pod, were biased but not significantly (p > 0.05) different from reference estimates. Body fat (%), assessed using Pea Pod, was not significantly different from reference estimates. The biological variability of fat-free mass density was 0.55% of the average value (1.0627 g/mL); (4) CONCLUSION: The results indicate that the Pea Pod system is accurate for groups of newborn, moderately premature infants. However, more studies where this system is used for premature infants are needed, and we provide suggestions regarding how to develop this area.
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Antropometría/métodos , Composición Corporal/fisiología , Recien Nacido Prematuro/fisiología , Femenino , Humanos , Recién Nacido , Masculino , Modelos Biológicos , Pletismografía/métodosRESUMEN
Mobile phones are becoming important instruments for assessing diet and energy intake. We developed the Tool for Energy Balance in Children (TECH), which uses a mobile phone to assess energy and food intake in pre-school children. The aims of this study were: (a) to compare energy intake (EI) using TECH with total energy expenditure (TEE) measured via doubly labelled water (DLW); and (b) to compare intakes of fruits, vegetables, fruit juice, sweetened beverages, candy, ice cream, and bakery products using TECH with intakes acquired by 24 h dietary recalls. Participants were 39 healthy, Swedish children (5.5 ± 0.5 years) within the ongoing Mobile-based Intervention Intended to Stop Obesity in Preschoolers (MINISTOP) obesity prevention trial. Energy and food intakes were assessed during four days using TECH and 24 h telephone dietary recalls. Mean EI (TECH) was not statistically different from TEE (DLW) (5820 ± 820 kJ/24 h and 6040 ± 680 kJ/24 h, respectively). No significant differences in the average food intakes using TECH and 24 h dietary recalls were found. All food intakes were correlated between TECH and the 24 h dietary recalls (ρ = 0.665-0.896, p < 0.001). In conclusion, TECH accurately estimated the average intakes of energy and selected foods and thus has the potential to be a useful tool for dietary studies in pre-school children, for example obesity prevention trials.
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Teléfono Celular , Registros de Dieta , Encuestas sobre Dietas/instrumentación , Dieta/estadística & datos numéricos , Aplicaciones Móviles/estadística & datos numéricos , Bebidas , Dulces , Preescolar , Encuestas sobre Dietas/métodos , Ingestión de Alimentos , Ingestión de Energía , Metabolismo Energético , Femenino , Frutas , Voluntarios Sanos , Humanos , Masculino , Recuerdo Mental , Reproducibilidad de los Resultados , Suecia , Verduras , AguaRESUMEN
Intrauterine factors influence infant size and body composition but the mechanisms involved are to a large extent unknown. We studied relationships between the body composition of pregnant women and variables related to their glucose homeostasis, i.e., glucose, HOMA-IR (homeostasis model assessment-insulin resistance), hemoglobin A1c and IGFBP-1 (insulin-like growth factor binding protein-1), and related these variables to the body composition of their infants. Body composition of 209 women in gestational week 32 and of their healthy, singleton and full-term one-week-old infants was measured using air displacement plethysmography. Glucose homeostasis variables were assessed in gestational week 32. HOMA-IR was positively related to fat mass index and fat mass (r2 = 0.32, p < 0.001) of the women. Maternal glucose and HOMA-IR values were positively (p ≤ 0.006) associated, while IGFBP-1 was negatively (p = 0.001) associated, with infant fat mass. HOMA-IR was positively associated with fat mass of daughters (p < 0.001), but not of sons (p = 0.65) (Sex-interaction: p = 0.042). In conclusion, glucose homeostasis variables of pregnant women are related to their own body composition and to that of their infants. The results suggest that a previously identified relationship between fat mass of mothers and daughters is mediated by maternal insulin resistance.
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Composición Corporal/fisiología , Glucosa/metabolismo , Homeostasis/fisiología , Tejido Adiposo , Femenino , Humanos , Recién Nacido , EmbarazoRESUMEN
BACKGROUND: Childhood obesity is an increasing health problem globally. Obesity may be established already at pre-school age. Further research in this area requires accurate and easy-to-use methods for assessing the intake of energy and foods. Traditional methods have limited accuracy, and place large demands on the study participants and researchers. Mobile phones offer possibilities for methodological advancements in this area since they are readily available, enable instant digitalization of collected data, and also contain a camera to photograph pre- and post-meal food items. We have recently developed a new tool for assessing energy and food intake in children using mobile phones called the Tool for Energy Balance in Children (TECH). OBJECTIVE: The main aims of our study are to (1) compare energy intake by means of TECH with total energy expenditure (TEE) measured using a criterion method, the doubly labeled water (DLW) method, and (2) to compare intakes of fruits and berries, vegetables, juice, and sweetened beverages assessed by means of TECH with intakes obtained using a Web-based food frequency questionnaire (KidMeal-Q) in 3 year olds. METHODS: In this study, 30 Swedish 3 year olds were included. Energy intake using TECH was compared to TEE measured using the DLW method. Intakes of vegetables, fruits and berries, juice, as well as sweetened beverages were assessed using TECH and compared to the corresponding intakes assessed using KidMeal-Q. Wilcoxon matched pairs test, Spearman rank order correlations, and the Bland-Altman procedure were applied. RESULTS: The mean energy intake, assessed by TECH, was 5400 kJ/24h (SD 1500). This value was not significantly different (P=.23) from TEE (5070 kJ/24h, SD 600). However, the limits of agreement (2 standard deviations) in the Bland-Altman plot for energy intake estimated using TECH compared to TEE were wide (2990 kJ/24h), and TECH overestimated high and underestimated low energy intakes. The Bland-Altman plots for foods showed similar patterns. The mean intakes of vegetables, fruits and berries, juice, and sweetened beverages estimated using TECH were not significantly different from the corresponding intakes estimated using KidMeal-Q. Moderate but statistically significant correlations (ρ=.42-.46, P=.01-.02) between TECH and KidMeal-Q were observed for intakes of vegetables, fruits and berries, and juice, but not for sweetened beverages. CONCLUSION: We found that one day of recordings using TECH was not able to accurately estimate intakes of energy or certain foods in 3 year old children.
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BACKGROUND: Childhood obesity is an increasing health problem globally. Overweight and obesity may be established as early as 2-5 years of age, highlighting the need for evidence-based effective prevention and treatment programs early in life. In adults, mobile phone based interventions for weight management (mHealth) have demonstrated positive effects on body mass, however, their use in child populations has yet to be examined. The aim of this paper is to report the study design and methodology of the MINSTOP (Mobile-based Intervention Intended to Stop Obesity in Preschoolers) trial. METHODS/DESIGN: A two-arm, parallel design randomized controlled trial in 300 healthy Swedish 4-year-olds is conducted. After baseline measures, parents are allocated to either an intervention- or control group. The 6- month mHealth intervention consists of a web-based application (the MINSTOP app) to help parents promote healthy eating and physical activity in children. MINISTOP is based on the Social Cognitive Theory and involves the delivery of a comprehensive, personalized program of information and text messages based on existing guidelines for a healthy diet and active lifestyle in pre-school children. Parents also register physical activity and intakes of candy, soft drinks, vegetables as well as fruits of their child and receive feedback through the application. Primary outcomes include body fatness and energy intake, while secondary outcomes are time spent in sedentary, moderate, and vigorous physical activity, physical fitness and intakes of fruits and vegetables, snacks, soft drinks and candy. Food and energy intake (Tool for Energy balance in Children, TECH), body fatness (pediatric option for BodPod), physical activity (Actigraph wGT3x-BT) and physical fitness (the PREFIT battery of five fitness tests) are measured at baseline, after the intervention (six months after baseline) and at follow-up (12 months after baseline). DISCUSSION: This novel study will evaluate the effectiveness of a mHealth program for mitigating gain in body fatness among 4-year-old children. If the intervention proves effective it has great potential to be implemented in child-health care to counteract childhood overweight and obesity. TRIAL REGISTRATION: ClinicalTrials.gov NCT02021786 ; 20 Dec 2013.
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Teléfono Celular , Internet , Obesidad Infantil/prevención & control , Evaluación de Programas y Proyectos de Salud/estadística & datos numéricos , Preescolar , Femenino , Frutas , Humanos , Estilo de Vida , Masculino , Obesidad/prevención & control , Aptitud Física , Proyectos de Investigación , Suecia , Envío de Mensajes de Texto , VerdurasRESUMEN
AIM: Existing studies suggest that weight and body composition of parents influence the size and body composition of their offspring, but are often inconclusive and conducted by means of inappropriate body composition methodology. Our aim was to study infant size and body composition variables in relation to body composition variables of their mothers and fathers in a well-nourished population using an accurate methodology. METHODS: Between 2008 and 2011, we used air displacement plethysmography to measure the body composition of 209 parent-infant units. Parents were measured when women were in gestational week 32. Their healthy, singleton, full-term infants were measured at 1 week. RESULTS: Infant fat-free mass in grams was positively related (p ≤ 0.007) to the fat-free mass in kilograms of the mothers (15.6 g/kg) and the fathers (9.1 g/kg). Furthermore, the fat mass of the daughters, but not of the sons, was positively related to the fat mass of the mothers (5.8 g/kg, p = 0.007). CONCLUSION: This study found associations between the fat-free mass of parents and infants and an association between the fat mass of mothers and their infant girls. These findings may help to understand early life factors behind overweight and obesity.
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Composición Corporal , Padre/estadística & datos numéricos , Recién Nacido/fisiología , Madres/estadística & datos numéricos , Adulto , Tamaño Corporal , Femenino , Humanos , Masculino , EmbarazoRESUMEN
A possibility to assess body composition during pregnancy is often important. Estimating body density (DB) and use the two-component model (2CM) to calculate total body fat (TBF) represents an option. However, this approach has been insufficiently evaluated during pregnancy. We evaluated the 2CM, and estimated fat-free mass (FFM) density and variability in 17 healthy women before pregnancy, in gestational weeks 14 and 32, and 2 weeks postpartum based on DB (underwater weighing), total body water (deuterium dilution) and body weight, assessed on these four occasions. TBF, calculated using the 2CM and published FFM density (TBF(2CM)), was compared to reference estimates obtained using the three-component model (TBF(3CM)). TBF(2CM) minus TBF(3CM) (mean ± 2SD) was -1.63 ± 5.67 (p = 0.031), -1.39 ± 7.75 (p = 0.16), -0.38 ± 4.44 (p = 0.49) and -1.39 ± 5.22 (p = 0.043) % before pregnancy, in gestational weeks 14 and 32 and 2 weeks postpartum, respectively. The effect of pregnancy on the variability of FFM density was larger in gestational week 14 than in gestational week 32. The 2CM, based on DB and published FFM density, assessed body composition as accurately in gestational week 32 as in non-pregnant adults. Corresponding values in gestational week 14 were slightly less accurate than those obtained before pregnancy.
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Tejido Adiposo , Composición Corporal , Modelos Biológicos , Periodo Periparto/fisiología , Periodo Posparto/fisiología , Adulto , Índice de Masa Corporal , Peso Corporal , Femenino , Voluntarios Sanos , Humanos , Modelos Lineales , EmbarazoRESUMEN
Accurate and easy-to-use methods to assess free-living energy expenditure in response to physical activity in young children are scarce. In the present study, we evaluated the capacity of (1) 4 d recordings obtained using the Actiheart (mean heart rate (mHR) and mean activity counts (mAC)) to provide assessments of total energy expenditure (TEE) and activity energy expenditure (AEE) and (2) a 7 d activity diary to provide assessments of physical activity levels (PAL) using three sets of metabolic equivalent (MET) values (PALTorun, PALAdolph and PALAinsworth) in forty-four and thirty-one healthy Swedish children aged 1·5 and 3 years, respectively. Reference TEE, PALref and AEE were measured using criterion methods, i.e. the doubly labelled water method and indirect calorimetry. At 1·5 years of age, mHR explained 8 % (P= 0·006) of the variation in TEE above that explained by fat mass and fat-free mass. At 3 years of age, mHR and mAC explained 8 (P= 0·004) and 6 (P= 0·03) % of the variation in TEE and AEE, respectively, above that explained by fat mass and fat-free mass. At 1·5 and 3 years of age, average PALAinsworth values were 1·44 and 1·59, respectively, and not significantly different from PALref values (1·39 and 1·61, respectively). By contrast, average PALTorun (1·5 and 3 years) and PALAdolph (3 years) values were lower (P< 0·05) than the corresponding PALref values. In conclusion, at both ages, Actiheart recordings explained a small but significant fraction of free-living energy expenditure above that explained by body composition variables, and our activity diary produced mean PAL values in agreement with reference values when using MET values published by Ainsworth.
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Composición Corporal , Calorimetría Indirecta , Metabolismo Energético/fisiología , Frecuencia Cardíaca/fisiología , Equivalente Metabólico/fisiología , Actividad Motora/fisiología , Preescolar , Femenino , Humanos , Lactante , Masculino , Valores de Referencia , Análisis de Regresión , Reproducibilidad de los Resultados , Autoinforme , AguaAsunto(s)
Tejido Adiposo , Índice de Masa Corporal , Sobrepeso/diagnóstico , Composición Corporal , Preescolar , Humanos , PletismografíaRESUMEN
Childhood overweight and obesity, a worldwide problem, is generally identified using BMI (body mass index). However, this application of BMI has been little investigated in children below 5 years of age due to a lack of appropriate methods to assess body composition. Therefore, we used air displacement plethysmography (ADP) to study 4.4-year old boys and girls since this method is accurate in young children if they accept the requirements of the measurement. The purpose was to analyze the relationship between BMI and body fat in these children. Body composition was assessed in 76 (43 boys, 33 girls) of the 84 children brought to the measurement session. Boys and girls contained 25.2 ± 4.7 and 26.8 ± 4.0% body fat, respectively. BMI-based cut-offs for overweight could not effectively identify children with a high body fat content. There was a significant (P < 0.001) but weak (r = 0.39) correlation between BMI and body fat (%). In conclusion, requirements associated with a successful assessment of body composition by means of ADP were accepted by most 4-year-olds. Furthermore, BMI-based cut-offs for overweight did not effectively identify children with a high body fatness and BMI explained only a small proportion of the variation in body fat (%) in this age group.
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Tejido Adiposo , Composición Corporal , Índice de Masa Corporal , Distribución de la Grasa Corporal , Estatura , Peso Corporal , Preescolar , Femenino , Humanos , Masculino , Sobrepeso/diagnóstico , PletismografíaRESUMEN
The prevalence of overweight and obesity in women has increased during the last decades. This is a serious concern since a high BMI before conception is an independent risk factor for many adverse outcomes of pregnancy. Therefore, dietary counseling, intended to stimulate weight loss in overweight and obese women prior to conception has recently been recommended. However, dieting with the purpose to lose weight may involve health risks for mother and offspring. We conducted a systematic literature review to identify papers investigating the effects of weight loss due to dietary interventions before conception. The objective of this study is to assess the effect of weight loss prior to conception in overweight or obese women on a number of health-related outcomes in mother and offspring using studies published between January 2000 and December 2011. Our first literature search produced 486 citations and, based on predefined eligibility criteria, 58 were selected and ordered in full text. Two group members read each paper. Fifteen studies were selected for quality assessment and two of them were considered appropriate for inclusion in evidence tables. A complementary search identified 168 citations with four papers being ordered in full text. The two selected studies provided data for overweight and obese women. One showed a positive effect of weight loss before pregnancy on the risk of gestational diabetes and one demonstrated a reduced risk for large-for-gestational-age infants in women with a BMI above 25 who lost weight before pregnancy. No study investigated the effect of weight loss due to a dietary intervention before conception. There is a lack of studies on overweight and obese women investigating the effect of dietary-induced weight loss prior to conception on health-related variables in mother and offspring. Such studies are probably lacking since they are difficult to conduct. Therefore, alternative strategies to control the body weight of girls and women of reproductive age are needed.
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Activity energy expenditure (AEE) during free-living conditions can be assessed using devices based on different principles. To make proper comparisons of different devices' capacities to assess AEE, they should be evaluated in the same population. Thus, in the present study we evaluated, in the same group of subjects, the ability of three devices to assess AEE in groups and individuals during free-living conditions. In twenty women, AEE was assessed using RT3 (three-axial accelerometry) (AEERT3), Actiheart (a combination of heart rate and accelerometry) (AEEActi) and IDEEA (a multi-accelerometer system) (AEEIDEEA). Reference AEE (AEEref) was assessed using the doubly labelled water method and indirect calorimetry. Average AEEActi was 5760 kJ per 24 h and not significantly different from AEEref (5020 kJ per 24 h). On average, AEERT3 and AEEIDEEA were 2010 and 1750 kJ per 24 h lower than AEEref, respectively (P < 0·001). The limits of agreement (± 2 sd) were 2940 (Actiheart), 1820 (RT3) and 2650 (IDEEA) kJ per 24 h. The variance for AEERT3 was lower than for AEEActi (P = 0·006). The RT3 classified 60 % of the women in the correct activity category while the corresponding value for IDEEA and Actiheart was 30 %. In conclusion, the Actiheart may be useful for groups and the RT3 for individuals while the IDEEA requires further development. The results are likely to be relevant for a large proportion of Western women of reproductive age and demonstrate that the procedure selected to assess physical activity can greatly influence the possibilities to uncover important aspects regarding interactions between physical activity, diet and health.
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Assessment of body fat (BF) in pregnant women is important when investigating the relationship between maternal nutrition and offspring health. Convenient and accurate body composition methods applicable during pregnancy are therefore needed. Air displacement plethysmography, as applied in Bod Pod, represents such a method since it can assess body volume (BV) which, in combination with body weight, can be used to calculate body density and body composition. However, BV must be corrected for the thoracic gas volume (TGV) of the subject. In non-pregnant women, TGV may be predicted using equations, based on height and age. It is unknown, however, whether these equations are valid during pregnancy. Thus, we measured the TGV of women in gestational week 32 (n 27) by means of plethysmography and predicted their TGV using equations established for non-pregnant women. Body weight and BV of the women was measured using Bod Pod. Predicted TGV was significantly (P = 0·033) higher than measured TGV by 6 % on average. Calculations in hypothetical women showed that this overestimation tended to be more pronounced in women with small TGV than in women with large TGV. The overestimation of TGV resulted in a small but significant (P = 0·043) overestimation of BF, equivalent to only 0·5 % BF, on average. A Bland-Altman analysis showed that the limits of agreement were narrow (from -1·9 to 2·9 % BF). Thus, although predicted TGV was biased and too high, the effect on BF was marginal and probably unimportant in many situations.