Duncan Radley

Children's residential weight-loss programs can work: a prospective cohort study of short-term outcomes for overweight and obese children.

Objective. The evidence base for child obesity treatment is weak. Childrens weight-loss camps, despite their popularity, have not been properly evaluated. This study evaluated the effectiveness of a residential weight-loss camp program for overweight and obese children. Methods. A total of 185 overweight children (mean age: 13.9 years) enrolled in 1 of 4 consecutive programs between 1999 and 2002 (intervention group) were compared with 94 children of similar ages who were not camp attendees, ie, 38 overweight children and 56 normal-weight children. The intervention group attended a 6-week (maximum) summer residential weight-loss camp. The program included a daily schedule of six 1-hour, skill-based, fun, physical activity sessions, moderate dietary restriction, and group-based educational sessions. All children were assessed for body weight, height, and other anthropometric measures, blood pressure, aerobic fitness, self-esteem, and selected sports skills. Results. Campers, who stayed for a mean of 29 days, lost 6.0 kg, reduced their BMI by 2.4 units, and reduced their BMI SD scores by 0.28. Fat mass decreased significantly (from 42.7 to 37.1 kg), whereas fat-free mass did not change. In contrast, both comparison groups gained weight during this period. Camp attendees also showed significant improvements in blood pressure, aerobic fitness, and self-esteem. Longer durations of stay were associated with greater improvements in outcomes. Conclusions. In the short term at least, this weight-loss program was effective across a range of health outcomes. Ongoing research is examining the maintenance of these improvements. Future research should investigate whether benefits can be generalized across weight-loss camps and how the intervention can be adapted to nonresidential, term-time settings.

Air-displacement plethysmography: here to stay.

Purpose of reviewAir-displacement plethysmography holds promise as an alternative to more traditional body composition techniques, although our understanding of air-displacement plethysmography is less than complete. Specifically, factors that influence its validity and application in certain populations, for example children, the obese, and athletes, must be better understood. This review will summarize recent findings on the validity and precision of air-displacement plethysmography and will focus primarily on papers published since 2004, with particular attention on its use in infants. Recent findingsThe most significant recent findings in the air-displacement plethysmography literature are mechanistic in nature specifically dealing with measurement issues such as heat, moisture, clothing, and recently, inter-device variability. SummaryIt is important to recognize that air-displacement plethysmography can be a practical instrument in the evaluation of body composition in a wide range of populations. Therefore, based on the body of literature that has emerged, air-displacement plethysmography appears to be a suitable and reliable instrument in the assessment of body composition. Of particular interest is its use in pediatric and obese individuals, areas requiring further study. Research is also needed to help us better understand sources of measurement error.

The effect of the Thanksgiving Holiday on weight gain

BackgroundMore people than ever are considered obese and the resulting health problems are evident. These facts highlight the need for identification of critical time periods for weight gain. Therefore the purpose was to assess potential changes that occur in body weight during the Thanksgiving holiday break in college students.Methods94 college students (23.0 ± 4.6 yrs, 72.1 ± 14.0 kg, 172.6 ± 9.3 cm, 24.0 ± 3.9 kg/m2) reported to the human body composition laboratory at the University of Oklahoma following a 6-hour fast with testing occurring prior to, and immediately following the Thanksgiving holiday break (13 ± 3 days). Body weight (BW) was assessed using a balance beam scale while participants were dressed in minimal clothing. Paired t-tests were used to assess changes in BW pre and post Thanksgiving holiday with additional analysis by gender, body mass index (BMI), and class standing (i.e. undergraduate vs. graduate).ResultsOverall, a significant (P < 0.05) increase in BW was found between pre (72.1 kg) and post (72.6 kg) Thanksgiving holiday. When stratified by gender and class standing a significant (P < 0.05) increase in body weight was observed between the pre and post Thanksgiving holiday in males (0.6 kg), females (0.4 kg) and graduate students (0.8 kg). When participants were classified by BMI as normal or as overweight/obese, a significant 1.0 kg BW gain was found (P < 0.05) in the overweight/obese (≥25 kg/m2) group compared to a non significant 0.2 kg gain in the normal group (<25 kg/m2).ConclusionThese data indicate that participants in our study gained a significant amount of BW (0.5 kg) during the Thanksgiving holiday. While an increase in BW of half a kilogram may not be cause for alarm, the increase could have potential long-term health consequences if participants retained this weight gain throughout the college year. Additionally, because the overweight/obese participants gained the greatest amount of BW, this group may be at increased risk for weight gain and further obesity development during the holiday season.

Does a high-protein diet improve weight loss in overweight and obese children?

Objective: To evaluate the effect of a high‐protein diet on anthropometry, body composition, subjective appetite, and mood sensations in overweight and obese children attending a residential weight‐loss camp.

Estimates of percentage body fat in young adolescents: a comparison of dual-energy X-ray absorptiometry and air displacement plethysmography

Objective: To evaluate the accuracy of percentage body fat (%fat) estimates from air displacement plethysmography (ADP) against an increasingly recognised criterion method, dual-energy X-ray absorptiometry (DXA), in young adolescents.Design: Cross-sectional evaluation.Setting: Leeds General Infirmary, Centre for Bone and Body Composition Research, Leeds, UK.Subjects: In all, 28 adolescents (12 males and 16 females), age (mean±s.d.) 14.9±0.5 y, body mass index 21.2±2.9 kg/m2 and body fat (DXA) 24.2±10.2% were assessed.Results: ADP estimates of %fat were highly correlated with those of DXA in both male and female subjects (r=0.84–0.95, all P<0.001; s.e.e.=3.42–3.89%). Mean %fat estimated by ADP using the Siri (1961) equation (ADPSiri) produced a nonsignificant overestimation in males (0.67%), and a nonsignificant underestimation in females (1.26%). Mean %fat estimated by ADP using the Lohman (1986) equations (ADPLoh) produced a nonsignificant underestimation in males (0.90%) and a significant underestimation in females (3.29%; P<0.01). Agreement between ADP and DXA methods was examined using the total error (TE) and methods of Bland and Altman (1986). Males produced a smaller TE (ADPSiri 3.28%; ADPLoh 3.49%) than females (ADPSiri 3.81%; ADPLoh 4.98%). The 95% limits of agreement were relatively similar for all %fat estimates, ranging from ±6.57 to ±7.58%. Residual plot analyses, of the individual differences between ADP and DXA, revealed a significant bias associated with increased %fat (DXA), only in girls (P<0.01).Conclusions: We conclude that ADP, at present, has unacceptably high limits of agreement compared to a criterion DXA measure. The ease of use, suitability for various populations and cost of ADP warrant further investigation of this method to establish biological variables that may influence the validity of body fat estimates.

UK student alcohol consumption: A cluster analysis of drinking behaviour typologies

Objective: To assess the extent to which university students are following UK Government advice regarding appropriate consumption of alcohol, and to investigate if students can be placed into distinct clusters based on their drinking behaviour. Design: A descriptive questionnaire study. Setting: One hundred and nineteen undergraduate students from Leeds Metropolitan University, UK. Method: An online survey, which included a diary to record daily alcohol consumption over the previous week, was completed during the winter of 2007/08. Cluster analysis was used to classify students into subgroups based on comparable alcohol-drinking characteristics. National recommended sensible drinking behaviour guidelines in terms of total weekly alcohol intake, maximum daily alcohol intake, number of alcohol-free days and estimated blood alcohol levels were used to compare drinking behaviour the previous week by age, sex and cluster group. Results: Consuming weekly alcohol levels considered hazardous was common (58%) with nearly 70% of responders binge drinking at least once over that period; most students (80%) were, however, following the government’s recommendation for two consecutive alcohol-free days per week. No significant differences in drinking behaviour by sex were found, but binge drinkers tended to be younger. Four distinct alcohol-drinking behaviour clusters were identified based on alcohol consumption frequency and quantity. Only students in the non or light drinkers group all remained within national recommended guidelines for weekly intake and alcohol-free days. Conclusion: Students who consume alcohol are commonly drinking daily and weekly alcohol levels in excess of national sensible drinking guidelines; most students, however, abstain from alcohol on at least two consecutive days. The four distinct drinking clusters suggest that students would benefit from targeted interventions. In particular, personalization of interventions to reflect the distinct patterns of drinking behaviour could increase intervention effectiveness.

Is BMI alone a sufficient outcome to evaluate interventions for child obesity

BACKGROUND BMI is often used to evaluate the effectiveness of childhood obesity interventions, but such interventions may have additional benefits independent of effects on adiposity. We investigated whether benefits to health outcomes following the Mind, Exercise, Nutrition…Do It! (MEND) childhood obesity intervention were independent of or associated with changes in zBMI. METHODS A total of 79 obese children were measured at baseline; 71 and 42 participants were followed-up at 6 and 12 months respectively, and split into four groups depending on magnitude of change in zBMI. Differences between groups for waist circumference, cardiovascular fitness, physical and sedentary activities, and self-esteem were investigated. RESULTS Apart from waist circumference and its z-score, there were no differences or trends across zBMI subgroups for any outcome. Independent of the degree of zBMI change, benefits in several parameters were observed in children participating in this obesity intervention. CONCLUSION We concluded that isolating a single parameter like zBMI change and neglecting other important outcomes is restrictive and may undermine the evaluation of childhood obesity intervention effectiveness.

From trial to population: a study of a family-based community intervention for childhood overweight implemented at scale

Objectives:To assess how outcomes associated with participation in a family-based weight management intervention (MEND 7–13, Mind, Exercise, Nutrition..Do it!) for childhood overweight or obesity implemented at scale in the community vary by child, family, neighbourhood and MEND programme characteristics.Methods/Subjects:Intervention evaluation using prospective service level data. Families (N=21 132) with overweight children are referred, or self-refer, to MEND. Families (participating child and one parent/carer) attend two sessions/week for 10 weeks (N=13 998; N=9563 with complete data from 1788 programmes across England). Sessions address diet and physical activity through education, skills training and motivational enhancement. MEND was shown to be effective in obese children in a randomised controlled trial (RCT). Outcomes were mean change in body mass index (BMI), age- and sex-standardised BMI (zBMI), self-esteem (Rosenberg scale) and psychological distress (Strengths and Difficulties Questionnaire) after the 10-week programme. Relationships between the outcome and covariates were tested in multilevel models adjusted for the outcome at baseline.Results:After adjustment for covariates, BMI reduced by mean 0.76 kg m−2 (s.e.=0.021, P<0.0001), zBMI reduced by mean 0.18 (s.e.=0.0038, P<0.0001), self-esteem score increased by 3.53 U  (s.e.=0.13, P<0.0001) and psychological distress score decreased by 2.65 U (s.e.=0.31, P<0.0001). Change in outcomes varied by participant, family, neighbourhood and programme factors. Generally, outcomes improved less among children from less advantaged backgrounds and in Asian compared with white children. BMI reduction under service conditions was slightly but not statistically significantly less than in the earlier RCT.Conclusions:The MEND intervention, when delivered at scale, is associated with improved BMI and psychosocial outcomes on average, but may work less well for some groups of children, and so has the potential to widen inequalities in these outcomes. Such public health interventions should be implemented to achieve sustained impact for all groups.

RCT of a High‐protein Diet on Hunger Motivation and Weight‐loss in Obese Children: An Extension and Replication

This study aimed to evaluate the weight loss and hunger motivation effects of an energy‐restricted high‐protein (HP) diet in overweight and obese children. In total, 95 overweight and obese children attended an 8‐week (maximum) program of physical activity, reduced‐energy intake, and behavior change education. Children were randomly assigned to one of two isoenergetic diets (standard (SP): 15% protein; HP: 25% protein), based on individually estimated energy requirements. Anthropometry and body composition were assessed at the start and end of the program and appetite and mood ratings completed on the first 3 consecutive weekdays of each week children attended camp. The HP diet had no greater effect on weight loss, body composition, or changes in appetite or mood when compared to the SP diet. Overall, campers lost 5.2 ± 3.0 kg in body weight and reduced their BMI standard deviation score (sds) by 0.25. Ratings of desire to eat increased significantly over the duration of the intervention, irrespective of diet. This is the third time we have reported an increase in hunger motivation in weight‐loss campers and replicates our previous failure to block this with a higher protein diet. Further work is warranted into the management of hunger motivation as a result of negative energy balance.

After the RCT: who comes to a family-based intervention for childhood overweight or obesity when it is implemented at scale in the community?

Background When implemented at scale, the impact on health and health inequalities of public health interventions depends on who receives them in addition to intervention effectiveness. Methods The MEND 7–13 (Mind, Exercise, Nutrition…Do it!) programme is a family-based weight management intervention for childhood overweight and obesity implemented at scale in the community. We compare the characteristics of children referred to the MEND programme (N=18 289 referred to 1940 programmes) with those of the population eligible for the intervention, and assess what predicts completion of the intervention. Results Compared to the MEND-eligible population, proportionally more children who started MEND were: obese rather than overweight excluding obese; girls; Asian; from families with a lone parent; living in less favourable socioeconomic circumstances; and living in urban rather than rural or suburban areas. Having started the programme, children were relatively less likely to complete it if they: reported ‘abnormal’ compared to ‘normal’ levels of psychological distress; were boys; were from lone parent families; lived in less favourable socioeconomic circumstances; and had participated in a relatively large MEND programme group; or where managers had run more programmes. Conclusions The provision and/or uptake of MEND did not appear to compromise and, if anything, promoted participation of those from disadvantaged circumstances and ethnic minority groups. However, this tendency was diminished because programme completion was less likely for those living in less favourable socioeconomic circumstances. Further research should explore how completion rates of this intervention could be improved for particular groups.