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Differences in physical activity (PA) might lead to long-term weight control. Studies on inverse relations between PA and changes in fatness among adolescents are limited. This paper examined the effect of PA on adolescents' changing body fatness over 5 years in Ho Chi Minh City (HCMC). Two hundred thirty-five boys and 247 girls who have had skinfold thickness measurements in the baseline survey in 2004 were selected to follow yearly. We estimated PA as the average number of accelerometers' counts/h. Slopes of triceps, sub-scapular skinfolds and BMI were calculated and classified as increasing or stable/decreasing. To assess the effects of the low level of activity (i.e. below the median of the average number of counts) on the fat gain (i.e. increasing slopes), relative risk and 95 % CI were estimated using Poisson regression. The average number of counts/h in boys (7·8) was significantly higher than that in girls (5·0) (P < 0·001). On average, active girls still gained 0·51 mm in triceps skinfold (TSF) over 5 years, while active boys lost 0·12 mm. After controlling for baseline energy intake, baseline triceps and baseline age, inactive adolescents were 1·39 times higher than active ones to increase the slope of triceps (95 % CI 1·19, 1·63). The risk ratio was 1·62 for those with more body fat at baseline. In general, inactive students gained substantially more subcutaneous fat, especially in their TSF, than more active ones. Thus, strategies to prevent adolescent obesity in HCMC should consider the important role of PA to control this problem in adolescents effectively. [ABSTRACT FROM AUTHOR]

Nutritional interventions often rely on subjective assessments of energy intake (EI), but these are susceptible to measurement error. To introduce an accelerometer-based intake-balance method for assessing EI using data from a time-restricted eating (TRE) trial. Nineteen participants with overweight/obesity (25–63 years old; 16 females) completed a 12-week intervention (NCT03129581) in a control group (unrestricted feeding; n 8) or TRE group (n 11). At the start and end of the intervention, body composition was assessed by dual-energy X-ray absorptiometry (DXA) and daily energy expenditure (EE) was assessed for 2 weeks via wrist-worn accelerometer. EI was back-calculated as the sum of net energy storage (from DXA) and EE (from accelerometer). Accelerometer-derived EI estimates were compared against estimates from the body weight planner of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Mean EI for the control group declined by 138 and 435 kJ/day for the accelerometer and NIDDK methods, respectively (both P ≥ 0·38), v. 1255 and 1469 kJ/day, respectively, for the TRE group (both P < 0·01). At follow-up, the accelerometer and NIDDK methods showed excellent group-level agreement (mean bias of −297 kJ/day across arms; standard error of estimate 1054 kJ/day) but high variability at the individual level (limits of agreement from −2414 to +1824 kJ/day). The accelerometer-based intake-balance method showed plausible sensitivity to change, and EI estimates were biologically and behaviourally plausible. The method may be a viable alternative to self-report EI measures. Future studies should assess criterion validity using doubly labelled water. [ABSTRACT FROM AUTHOR]

Eating architecture is a term that describes meal frequency, meal timing and meal size and the daily variation in each of these. The aim of this study was to determine the relationship between components of eating architecture on body fat and markers of glycaemic control in healthy adults at increased risk of type 2 diabetes (T2DM). Participants (n 73, 39 males, age 58·8 (8·1) years, BMI 33·4 (4·4) kg/m2) recorded food intake and wore accelerometers and continuous glucose monitors (CGM) for 7–14 d under free-living conditions. Body fat and glycated Hb (HbA1c) were also measured. The mean and day-to-day variation (calculated as the standard deviation during the monitoring period) of each component of eating architecture were calculated. Multivariable linear regression models were constructed for three separate outcome variables (body fat mass, mean CGM glucose and HbA1c) for each component of eating architecture before and after adjustment for confounders. Higher variability in the time of first meal consumption was associated with increased body fat mass after adjusting for confounders (β = 0·227, 95 % CI: 0·019, 0·434, P = 0·033). Increased variability in the time lag from waking to first meal consumption was also positively associated with increased HbA1c after adjustment (β = 0·285, 95 % CI: 0·040, 0·530, P = 0·023). Low day-to-day variability in first meal consumption was associated with lower body fat and improved glucose control in adults at increased risk of T2DM. Routine consumption of meals may optimise temporal regulation to anticipate and respond appropriately to a glucose challenge. [ABSTRACT FROM AUTHOR]

Fe deficiency has negative effects on voluntary physical activity (PA); however, the impact of consuming Fe-biofortified staple foods on voluntary PA remains unclear. This study compared the effects of consuming Fe-biofortified pearl millet or a conventional pearl millet on measures of voluntary PA in Indian schoolchildren (ages 12–16 years) during a 6-month randomised controlled feeding trial. PA data were collected from 130 children using Actigraph GT3X accelerometers for 6 d at baseline and endline. Minutes spent in light and in moderate-to-vigorous PA were calculated from accelerometer counts using Crouter's refined two-regression model for children. Mixed regression models adjusting for covariates were used to assess relationships between intervention treatment or change in Fe status and PA. Children who consumed Fe-biofortified pearl millet performed 22·3 (95 % CI 1·8, 42·8, P = 0·034) more minutes of light PA each day compared with conventional pearl millet. There was no effect of treatment on moderate-to-vigorous PA. The amount of Fe consumed from pearl millet was related to minutes spent in light PA (estimate 3·4 min/mg Fe (95 % CI 0·3, 6·5, P = 0·031)) and inversely related to daily sedentary minutes (estimate −5·4 min/mg Fe (95 % CI –9·9, −0·9, P = 0·020)). Consuming Fe-biofortified pearl millet increased light PA and decreased sedentary time in Indian schoolchildren in a dose-dependent manner. [ABSTRACT FROM AUTHOR]

Objective: To determine if 7 d physical activity (PA) predicts energy intake over the same days and if PA on a given day predicts energy intake on the same day, the next day or subsequent days.Design: A 7 d prospective investigation. PA was measured using accelerometers worn for seven consecutive days. During the same week, total energy intake (including alcohol) was assessed using weighed food records.Setting: Twenty cities in the USA.Subjects: Three hundred middle-aged women.Results: After controlling for the covariates, energy intake was 36 (se 8) kJ higher for each additional 100000 activity counts (F=19·0, P<0·0001), based on the entire week of monitoring. Women with Low PA (n 75) had a mean energy intake of 8364 (sd 1235) kJ/d (1998 (sd 295) kcal/d), those with Moderate PA (n 150) consumed 8523 (sd 1264) kJ/d (2036 (sd 302) kcal/d) and those with High PA (n 75) consumed 9079 (sd 1473) kJ/d (2169 (sd 352) kcal/d; F=6·4, P=0·0019), a 5023 kJ/d (1200 kcal/d) difference between the High and Low PA groups. PA on a given day was predictive of energy consumption on the same day on four of the seven monitored days, and was predictive of energy intake the next day, with five of six associations significant. PA was not consistently predictive of energy intake on days beyond the next day.Conclusions: Over 7 d, PA and energy consumption tend to be positively related. Considered day to day, increased PA is weakly associated with increased energy intake the following day and, to a lesser extent, the same day. Therefore, managing weight by increasing PA may not result in the energy deficit expected. [ABSTRACT FROM AUTHOR]

It is widely assumed that nutrition can improve school performance in children; however, evidence remains limited and inconclusive. In the present study, we investigated whether serving healthy school meals influenced concentration and school performance of 8- to 11-year-old Danish children. The OPUS (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet) School Meal Study was a cluster-randomised, controlled, cross-over trial comparing a healthy school meal programme with the usual packed lunch from home (control) each for 3 months (NCT 01457794). The d2 test of attention, the Learning Rating Scale (LRS) and standard tests on reading and mathematics proficiency were administered at baseline and at the end of each study period. Intervention effects were evaluated using hierarchical mixed models. The school meal intervention did not influence concentration performance (CP; primary outcome, n 693) or processing speed; however, the decrease in error percentage was 0·18 points smaller (P< 0·001) in the intervention period than in the control period (medians: baseline 2·03 %; intervention 1·46 %; control 1·37 %). In contrast, the intervention increased reading speed (0·7 sentence, P= 0·009) and the number of correct sentences (1·8 sentences, P< 0·001), which corresponded to 11 and 25 %, respectively, of the effect of one school year. The percentage of correct sentences also improved (P< 0·001), indicating that the number correct improved relatively more than reading speed. There was no effect on overall math performance or outcomes from the LRS. In conclusion, school meals did not affect CP, but improved reading performance, which is a complex cognitive activity that involves inference, and increased errors related to impulsivity and inattention. These findings are worth examining in future trials. [ABSTRACT FROM PUBLISHER]

ObjectiveThe aim of the present study was to investigate if context-specific measures of parental-reported physical activity and sedentary behaviour are associated with objectively measured physical activity and sedentary time in children.DesignCross-sectional study.SettingSeven European countries taking part in the IDEFICS (Identification and Prevention of Dietary- and Lifestyle-induced Health Effects in Children and Infants) study.SubjectsData were analysed from 2–9-year-old children (n 5982) who provided both parental-reported and accelerometer-derived physical activity/sedentary behaviour measures. Parents reported their children’s daily screen-time, weekly sports participation and daily outdoor playtime by means of the Outdoor Playtime Checklist (OPC) and Outdoor Playtime Recall Questions (OPRQ).ResultsSports participation, OPC- and OPRQ-derived outdoor play were positively associated with accelerometer-derived physical activity. Television viewing and computer use were positively associated with accelerometer-derived sedentary time. All parental-reported measures that were significantly associated with accelerometer outcomes explained only a minor part of the variance in accelerometer-derived physical activity or sedentary time.ConclusionsParental-reported measures of physical activity and sedentary behaviour are not useful as a proxy for 2–9-year-old children’s physical activity and sedentary time. Findings do not preclude the use of context-specific measures but imply that conclusions should be limited to the context-specific behaviours that are actually measured. Depending on the aim of the study, future research should carefully consider the choice of measurements, including the use of subjective or objective measures of the behaviour of interest or a combination of both. [ABSTRACT FROM PUBLISHER]

The present study was conducted to determine the association between fibre intake and insulin resistance in 264 women using a cross-sectional design. Insulin resistance was indexed using homeostasis model assessment of insulin resistance (HOMA-IR) (US formula: fasting insulin (μU/ml) × fasting glucose (mg/dl)/405 international formula: fasting glucose (mmol/l) × fasting insulin (μU/l)/22.5). Fibre and energy consumption were assessed using 7 d weighed food records. Fibre was expressed as g/4184 kJ (1000 kcal). Body fat percentage (BF%) was measured using the BOD POD, and physical activity (PA) was ascertained using Actigraph accelerometers (Health One Technology) worn for seven consecutive days. Women with high total fibre intakes (F= 4·58, P= 0·0332) or high soluble fibre intakes (F= 7·97, P= 0·0051) had significantly less insulin resistance than their counterparts. Participants with high insoluble fibre intakes did not differ from their counterparts (F= 0·7, P= 0·6875). Adjusting for either PA or BF% weakened the relationships significantly. Controlling for BF% nullified the total fibre–HOMA-IR link (F= 1·96, P= 0·1631) and attenuated the association between soluble fibre and HOMA-IR by 32 % (F= 6·86, P= 0·0094). To create dichotomous variables, fibre intake and HOMA-IR were each divided into two categories using the median (low and high). In women who had high soluble fibre intake (upper 50 %), the OR of having an elevated HOMA-IR level was 0·58 (95 % CI 0·36, 0·94) times that of women with low soluble fibre intake (lower 50 %). After controlling for all of the potential confounding factors simultaneously, the OR was 0·52 (95 % CI 0·29, 0·93). High fibre intake, particularly soluble fibre, is significantly related to lower levels of insulin resistance in women. Part of this association is a function of differences in PA and BF%. [ABSTRACT FROM PUBLISHER]

The present study was intended to examine whether ponderal index (PI) at birth modifies the effect of the fat mass and obesity associated (FTO) rs9939609 polymorphism on adiposity in European adolescents. A total of 628 adolescents aged 14·4 (se 1·3) years (56·8 % female) were recruited. PI was calculated from parental reports of birth weight and length (kg/m3), and the BMI (kg/m2), body fat percentage and fat mass index (FMI, kg/m2) were calculated. The rs9939609 polymorphism was genotyped and physical activity assessed by accelerometry. Sex, duration of pregnancy, pubertal status, centre and physical activity were used as confounders in all the analyses. The minor A allele of the FTO rs9939609 was significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) but not with PI. Significant interactions between PI and the rs9939609 polymorphism in terms of body fat percentage (P = 0·002) and FMI (P = 0·017) were detected. However, this polymorphism was only significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) in adolescents in the lower PI tertile. Indeed, both body fat percentage and FMI were higher in those adolescents in the lower PI tertile carrying the A allele of the FTO rs9939609 polymorphism than in those with the TT genotype (25·0 (se 0·8) v. 22·1 (se 1·0) %, adjusted P = 0·030 and 5·6 (se 0·3) v. 4·6 (se 0·4) kg/m2, P = 0·031, respectively). Our findings suggest that those adolescents born with lower PI could be more vulnerable to the influence of the A risk allele of the FTO polymorphism on total adiposity content. [ABSTRACT FROM PUBLISHER]

ObjectiveTo investigate the reliability and the validity of the long format, Chinese version of the International Physical Activity Questionnaire (IPAQ-LC).DesignCross-sectional study, examining the reliability and validity of the IPAQ-LC compared with a physical activity log (PA-log) and objective accelerometry.SettingSelf-reported physical activity (PA) in Hong Kong adults.SubjectsA total of eighty-three Chinese adults (forty-seven males, thirty-six females) were asked to wear an ActiTrainer accelerometer (MTI-ActiGraph, Fort Walton Beach, FL, USA) for >10 h over 7 d, to complete a PA-log at the end of each day and to complete the IPAQ-LC on day 8. On a sub-sample of twenty-eight adults the IPAQ-LC was also administered on day 11 to assess its reliability.ResultsThe IPAQ-LC had good test–retest reliability for grouped activities, with intra-class correlation coefficients ranging from 0·74 to 0·97 for vigorous, moderate, walking and total PA, with between-test effect sizes that were small (<0·49). The Spearman correlation coefficients were statistically significant for vigorous PA (r = 0·28), moderate + walking PA (r = 0·27), as well as overall PA (r = 0·35), when compared with the accelerometry-based criterion measures, but none of the IPAQ activity categories correlated significantly with the PA-log. In absolute units, only the IPAQ light and overall PA did not differ significantly from the accelerometry measures, yet overall PA was able to faithfully discriminate between quartiles of PA (P = 0·019) when compared to accelerometry.ConclusionsThe IPAQ-LC demonstrated adequate reliability and showed sufficient evidence of validity in assessing overall levels of habitual PA to be used on Hong Kong adults. [ABSTRACT FROM AUTHOR]

ObjectiveTo examine the reliability and convergent validity of physical activity (PA) and inactivity estimates obtained with the past-week Modifiable Activity Questionnaire (PWMAQ).DesignThe PWMAQ, an interviewer-administered questionnaire, was administered twice, one week apart, during visits 3 and 4 of six total visits. Intra-class correlation coefficients (ICC) between administrations of the PWMAQ were used to assess the reliability of summary estimates. Spearman rank-order correlation coefficients (ρ) were used to examine the associations of PWMAQ summary estimates with temporally matched and averaged accelerometer data in all participants and then stratified by whether the data were reflective of usual PA.SettingData were obtained from the Evaluation of Physical Activity Measures in Middle-Aged Women (PAW) study.SubjectsSixty-six women, mean age 52·6 (sd 5·4) years.ResultsThe reliability of the PWMAQ physical inactivity estimate suggested substantial agreement over one week (ICC = 0·77, 95 % CI 0·57, 0·82; P < 0·0001). With the exception of light-intensity PA, the PWMAQ leisure PA estimate was significantly associated with averaged accelerometer data (ρ = 0·33–0·76; P < 0·05). For both temporally matched and averaged accelerometer data, correlation coefficients were higher between the PWMAQ estimate and moderate-walk- to vigorous-intensity PA in those who indicated that reported activity was reflective of usual PA; however, the association with moderate-lifestyle-intensity PA was higher in those reporting that data were not reflective.ConclusionsThe PWMAQ is a reliable and valid measure of leisure PA levels in middle-aged women and supports subsequent studies evaluating this questionnaire in other population subgroups. [ABSTRACT FROM AUTHOR]

Measurement of energy expenditure in humans is required to assess metabolic needs, fuel utilisation, and the relative thermic effect of different food, drink, drug and emotional components. Indirect and direct calorimetric and non-calorimetric methods for measuring energy expenditure are reviewed, and their relative value for measurement in the laboratory and field settings is assessed. Where high accuracy is required and sufficient resources are available, an open-circuit indirect calorimeter can be used. Open-circuit indirect calorimeters can employ a mask, hood, canopy or room/chamber for collection of expired air. For short-term measurements, mask, hood or canopy systems suffice. Chamber-based systems are more accurate for the long-term measurement of specified activity patterns but behaviour constraints mean they do not reflect real life. Where resources are limited and/or optimum precision can be sacrificed, flexible total collection systems and non-calorimetric methods are potentially useful if the limitations of these methods are appreciated. The use of the stable isotope technique, doubly labelled water, enables total daily energy expenditure to be measured accurately in free-living subjects. The factorial method for combining activity logs and data on the energy costs of activities can also provide detailed information on free-living subjects. [ABSTRACT FROM AUTHOR]