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    ABSTRACT: Physical inactivity is responsible for 5.3 million deaths annually worldwide. To measure physical activity energy expenditure, the doubly labeled water (DLW) method is the gold standard. However, questionnaires and accelerometry are more widely used. We compared physical activity measured by accelerometer and questionnaire against total (TEE) and physical activity energy expenditure (PAEE) estimated by DLW. TEE, PAEE (TEE minus resting energy expenditure) and body composition were measured using the DLW technique in 25 adolescents (16 girls) aged 13 years living in Pelotas, Brazil. Physical activity was assessed using the Actigraph accelerometer and by self-report. Physical activity data from accelerometry and self-report were tested against energy expenditure data derived from the DLW method. Further, tests were done to assess the ability of moderate-to-vigorous intensity physical activity (MVPA) to predict variability in TEE and to what extent adjustment for fat and fat-free mass predicted the variability in TEE. TEE varied from 1,265 to 4,143 kcal/day. It was positively correlated with physical activity (counts) estimated by accelerometry (rho = 0.57; p = 0.003) and with minutes per week of physical activity by questionnaire (rho = 0.41; p = 0.04). An increase of 10 minutes per day in moderate-to-vigorous intensity physical activity (MVPA) relates to an increase in TEE of 141 kcal/day. PAEE was positively correlated with accelerometry (rho = 0.64; p = 0.007), but not with minutes per week of physical activity estimated by questionnaire (rho = 0.30; p = 0.15). Physical activity by accelerometry explained 31% of the vssariability in TEE. By incorporating fat and fat-free mass in the model, we were able to explain 58% of the variability in TEE. Objectively measured physical activity significantly contributes to the explained variance in both TEE and PAEE in Brazilian youth. Independently, body composition also explains variance in TEE, and should ideally be taken into account when using accelerometry to predict energy expenditure values.
    PLoS ONE 11/2013; 8(11):e77036. DOI:10.1371/journal.pone.0077036
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    ABSTRACT: The aim of this study was to report outcomes of the UK service level delivery of MEND (Mind,Exercise,Nutrition...Do it!) 5-7, a multicomponent, community-based, healthy lifestyle intervention designed for overweight and obese children aged 5-7 years and their families. Repeated measures. Community venues at 37 locations across the UK. 440 overweight or obese children (42% boys; mean age 6.1 years; body mass index (BMI) z-score 2.86) and their parents/carers participated in the intervention. MEND 5-7 is a 10-week, family-based, child weight-management intervention consisting of weekly group sessions. It includes positive parenting, active play, nutrition education and behaviour change strategies. The intervention is designed to be scalable and delivered by a range of health and social care professionals. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was BMI z-score. Secondary outcome measures included BMI, waist circumference, waist circumference z-score, children's psychological symptoms, parenting self-efficacy, physical activity and sedentary behaviours and the proportion of parents and children eating five or more portions of fruit and vegetables. 274 (62%) children were measured preintervention and post-intervention (baseline; 10-weeks). Post-intervention, mean BMI and waist circumference decreased by 0.5 kg/m(2) and 0.9 cm, while z-scores decreased by 0.20 and 0.20, respectively (p<0.0001). Improvements were found in children's psychological symptoms (-1.6 units, p<0.0001), parent self-efficacy (p<0.0001), physical activity (+2.9 h/week, p<0.01), sedentary activities (-4.1 h/week, p<0.0001) and the proportion of parents and children eating five or more portions of fruit and vegetables per day (both p<0.0001). Attendance at the 10 sessions was 73% with a 70% retention rate. Participation in the MEND 5-7 programme was associated with beneficial changes in physical, behavioural and psychological outcomes for children with complete sets of measurement data, when implemented in UK community settings under service level conditions. Further investigation is warranted to establish if these findings are replicable under controlled conditions.
    BMJ Open 05/2013; 3(5). DOI:10.1136/bmjopen-2013-002607
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    ABSTRACT: The concept that early growth has long-term biological effects is based on extensive studies in animals dating from the 1930s. More recently, compelling evidence for a long-term influence of early growth on later health has also emerged in humans. Substantial data now support the hypothesis that 'accelerated', or too fast infant growth, increases the propensity to obesity, glucose intolerance, raised blood pressure, dyslipidaemia and endothelial dysfunction, the clustering of risk factors which predispose to the development of atherosclerotic cardiovascular disease (CVD). The association between infant growth and these risk factors is strong, consistent, shows a dose-response effect, and is biologically plausible. Moreover, experimental data from prospective randomized controlled trials strongly support a causal link between infant growth and later cardiovascular risk. These observations suggest, therefore, that the primary prevention of CVD should begin from as early as the first few months of life. The present review considers this evidence, the underlying mechanisms involved, and its implications for public health.
    World review of nutrition and dietetics 01/2013; 106:162-7. DOI:10.1159/000342580
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    ABSTRACT: BACKGROUND: A routine pediatric clinical assessment of body composition is increasingly recommended but has long been hampered by the following 2 factors: a lack of appropriate techniques and a lack of reference data with which to interpret individual measurements. Several techniques have become available, but reference data are needed. OBJECTIVE: We aimed to provide body-composition reference data for use in clinical practice and research. DESIGN: Body composition was measured by using a gold standard 4-component model, along with various widely used reference and bedside methods, in a large, representative sample of British children aged from 4 to ≥20 y. Measurements were made of anthropometric variables (weight, height, 4 skinfold thicknesses, and waist girth), dual-energy X-ray absorptiometry, body density, bioelectrical impedance, and total body water, and 4-component fat and fat-free masses were calculated. Reference charts and SD scores (SDSs) were constructed for each outcome by using the lambda-mu-sigma method. The same outcomes were generated for the fat-free mass index and fat mass index. RESULTS: Body-composition growth charts and SDSs for 5-20 y were based on a final sample of 533 individuals. Correlations between SDSs by using different techniques were ≥0.68 for adiposity outcomes and ≥0.80 for fat-free mass outcomes. CONCLUSIONS: These comprehensive reference data for pediatric body composition can be used across a variety of techniques. Together with advances in measurement technologies, the data should greatly enhance the ability of clinicians to assess and monitor body composition in routine clinical practice and should facilitate the use of body-composition measurements in research studies.
    American Journal of Clinical Nutrition 10/2012; 96(6). DOI:10.3945/ajcn.112.036970
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    ABSTRACT: Because obesity is associated with diverse chronic diseases, little attention has been directed to the multiple beneficial functions of adipose tissue. Adipose tissue not only provides energy for growth, reproduction and immune function, but also secretes and receives diverse signaling molecules that coordinate energy allocation between these functions in response to ecological conditions. Importantly, many relevant ecological cues act on growth and physique, with adiposity responding as a counterbalancing risk management strategy. The large number of individual alleles associated with adipose tissue illustrates its integration with diverse metabolic pathways. However, phenotypic variation in age, sex, ethnicity and social status is further associated with different strategies for storing and using energy. Adiposity therefore represents a key means of phenotypic flexibility within and across generations, enabling a coherent life-history strategy in the face of ecological stochasticity. The sensitivity of numerous metabolic pathways to ecological cues makes our species vulnerable to manipulative globalized economic forces. The aim of this article is to understand how human adipose tissue biology interacts with modern environmental pressures to generate excess weight gain and obesity. The disease component of obesity might lie not in adipose tissue itself, but in its perturbation by our modern industrialized niche. Efforts to combat obesity could be more effective if they prioritized 'external' environmental change rather than attempting to manipulate 'internal' biology through pharmaceutical or behavioral means.
    Disease Models and Mechanisms 09/2012; 5(5):595-607. DOI:10.1242/dmm.009613
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    ABSTRACT: The WHO recommends exclusive breastfeeding (EBF) for 6 mo after birth. However, the time at which breast milk ceases to provide adequate energy and nutrition, requiring the introduction of complementary foods, remains unclear. Most studies that investigated this issue were observational and potentially confounded by variability in social circumstances or infant growth. We hypothesized that EBF infants would consume more breast milk at age 6 mo than infants receiving breast milk and complementary foods. We measured anthropometric outcomes, body composition, and breast-milk intake at age 6 mo in infants who were randomly assigned at age 4 mo either to 6-mo EBF or to the introduction of complementary foods with continued breastfeeding. We recruited 119 infants from health centers in Reykjavik and neighboring municipalities in Iceland. In 100 infants who completed the protocol (50/group), breast-milk intake was measured by using stable isotopes, and complementary food intakes were weighed over 3 d in the complementary feeding (CF) group. Breast-milk intake was 83 g/d (95% CI: 19, 148 g/d) greater in EBF (mean ± SD: 901 ± 158 g/d) than in CF (818 ± 166 g/d) infants and was equivalent to 56 kcal/d; CF infants obtained 63 ± 52 kcal/d from complementary foods. Estimated total energy intakes were similar (EBF: 560 ± 98 kcal/d; CF: 571 ± 97 kcal/d). Secondary outcomes (anthropometric outcomes, body composition) did not differ significantly between groups. On a group basis, EBF to age 6 mo did not compromise infant growth or body composition, and energy intake at age 6 mo was comparable to that in CF infants whose energy intake was not constrained by maternal breast-milk output.
    American Journal of Clinical Nutrition 05/2012; 96(1):73-9. DOI:10.3945/ajcn.111.030403
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    ABSTRACT: To evaluate whether dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS) classify the same children as 'abnormal' (SD (z) score (SDS) ≤-2). Speed of sound (SOS) was measured at the radius and tibia using QUS and lumbar spine bone mineral density (BMD) using DXA in 621 subjects aged 5-20 years; healthy 412, cystic fibrosis 117 and obese 92. BMD SDS positively (p<0.001) and tibia SOS SDS negatively correlated with size (p<0.05). Disagreement between DXA and QUS for 'abnormal' scans occurred in 6-31%. Those with abnormal BMD and normal SOS SDS had lower mean BMI SDS than those with normal BMD and abnormal SOS SDS. SOS measurements were unobtainable in some children, especially in the obese group. DXA and QUS identify different individuals as 'abnormal'. Agreement between BMD and tibia SOS is lower in obese subjects. Without a gold-standard, it is difficult to determine which technique is more 'correct'.
    Archives of Disease in Childhood 05/2012; 97(9):822-4. DOI:10.1136/archdischild-2011-301326
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    ABSTRACT: Obesity is widely assumed to be associated with economic affluence; it has therefore been assumed to become more common with economic development. However, obesity has also been associated with poverty. These contrary findings highlight the need for an examination of the contribution of social and economic factors to the global distribution of obesity. Males and females may be differently exposed to social and economic inequality, however few studies have considered possible gender differences in the association between socio-economic indices and obesity prevalence. We analysed between-country associations between obesity prevalence and three social or economic indices: per capita gross domestic product (GDP), the Gini index of national wealth inequality, and the gender inequality index (GII). We considered the genders separately, the gender average, and also the gender difference (female excess) in obesity prevalence. Across 68 countries listing sample size, there were 3 obese women for every 2 obese men. Within populations, obesity prevalence in males and females was strongly correlated (r = 0.74), however, only 17% of the female excess prevalence was accounted for by the gender-average prevalence. In both genders, there was a positive association between obesity prevalence and GDP that attenuated at higher GDP levels, with this association weaker in females than males. Adjusting for GDP, both the Gini index and GII were associated with excess female obesity. These analyses highlight significant gender differences in the global distribution of obesity, and a gender difference in the association of obesity prevalence with socio-economic factors. The magnitude of female excess obesity is not constant across populations, and is greater in countries characterised by gender inequality and lower GDP. These findings indicate that improving women's status may be a key area for addressing the global obesity epidemic over the long term, with potential benefits for the women themselves and for their offspring.
    Social Science [?] Medicine 04/2012; 75(3):482-90. DOI:10.1016/j.socscimed.2012.03.029
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    International Journal of Epidemiology 02/2012; 41(1):229-35. DOI:10.1093/ije/dyr239
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    ABSTRACT: In the 19th century, two "ecogeographical rules" were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue (the heat-producing component) or fat (energy stores). Data on weight, height, and two skinfold thickness were obtained from the literature for 137 nonindustrialized populations, providing 145 male and 115 female individual samples. A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index (BMI), and increasing triceps but not subscapular skinfold. After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system. Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.
    American Journal of Physical Anthropology 02/2012; 147(2):169-86. DOI:10.1002/ajpa.21591
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