Children with acute lymphoblastic leukaemia (ALL) typically gain weight at excessive rates during and after therapy, and a high proportion of young adult survivors are obese. Previous studies have failed to identify the abnormalities in energy balance that predispose these children to obesity. The aim of this study was to determine the cause of excess weight gain in children treated for ALL by testing the hypothesis that energy expenditure is reduced in these patients. Twenty children [9 boys, 11 girls; mean age 10.9 (3.2) y] treated for ALL who had shown excess weight gain, but were not obese [mean body mass index SD score 0.70 (1.04)], were closely and individually matched with 20 healthy control children [9 boys, 11 girls; mean age 10.7 (3.0) y; mean body mass index SD score 0.27 (0.91)]. In each child we measured total energy expenditure by doubly-labeled water method, resting energy expenditure, energy expended on habitual physical activity, and energy intake. Total energy expenditure was significantly higher in control subjects than in patients: mean paired difference 1185 kJ/d (282 kcal/d), 95% confidence interval (CI) 218-2152. This difference was largely due to reduced energy expended on habitual physical activity in the patients. Resting energy expenditure was lower in the patients: mean paired difference 321 kJ/d (76 kcal/d), 95% CI 100-541. Energy intake was also lower in the patients: mean paired difference 1001 kJ/d (238 kcal/d), 95% CI 93-1909. Children treated for ALL are predisposed to excess weight gain, and subsequently obesity, by reduced total energy expenditure secondary to reduced habitual physical activity. Prevention of obesity in ALL should focus on modest increases in habitual physical activity, modest restriction of dietary intake, and monitoring of excess weight gain.

OBJECTIVE: To test whether excess weight gain in patients treated for childhood acute lymphoblastic leukaemia (ALL) was predictable using patient characteristics at diagnosis. DESIGN AND SUBJECTS: Longitudinal study of changes in body mass index (BMI) in all 98 patients treated in Scotland on treatment protocol MRC UKALL-XI who had reached at least 3 y post-diagnosis in ®rst remission. MEASUREMENTS: The in¯uence of the following variables on changes in BMI, expressed as a standard deviation score (SDS), was tested using variable selection techniques and classi®cation and regression trees: BMI SDS at diagnosis; age at diagnosis; gender; socioeconomic status; treatment. RESULTS: Prevalence of obesity (BMI SDSb2.0) was`2% at diagnosis, but increased to 16% at 3 y. Gain in BMI SDS was signi®cantly inversely in¯uenced by BMI SDS at diagnosis (P`0.01) and age at diagnosis (P`0.01). CONCLUSION: Obesity is common in ALL by the end of therapy, and is more likely in children who are younger and thinner at diagnosis. Excess weight gain was not readily predictable from routinely collected information available at diagnosis and so all children treated for ALL should be considered`at risk' of excess weight gain and the target of obesity prevention.

The aim of the present study was to determine the reproducibility of measurement of resting metabolic rate (RMR) using a ventilated-hood indirect calorimeter in children using a short protocol suitable for the outpatient setting or home visit. The protocol consisted of an overnight (10-12 h) fast, 5-10 min supine rest, 5-10 min 'settling in' under the ventilated hood, and 12-16 min of measurement. Three measurements of RMR were made in eighteen healthy children (nine boys, nine girls, aged 6-11 years) on alternate days. Reproducibility of RMR was assessed using a reproducibility index and by calculating the CV for intra-individual measurements. The mean CV was 2⋅6 (SD 1⋅7)% and the reproducibility index was 95⋅0 %, indicating excellent reliability. The short protocol had higher reproducibility than more stringent protocols described in the literature. The new protocol has a number of practical advantages and should be adequate for most clinical or research purposes. Children: Resting energy expenditure: Reproducibility

The prevalence of obesity in children, as in adults, is increasing dramatically. The extent to which this is due to reduced energy expenditure, increased energy intake, or both, is unclear at present. This in part reflects the limitations of existing models of the pre-obese state. In childhood acute lymphoblastic leukaemia (ALL), patients typically gain weight excessively during and after 2 years of therapy, and are at high risk of becoming obese. Previous studies have failed to identify the cause of obesity in these patients. We have tested the hypothesis that excess weight gain in ALL is due to reduced total energy expenditure (TEE), measured using the doubly-labelled water method, and have identified risk factors for excess weight gain in ALL. Pre-obese children with ALL in the dynamic phase of weight gain are less physically active than their peers, with a reduced TEE of approximately 1.2 (95 % CI 0.2, 2.2) MJ/d. While other factors might contribute to excess weight gain, lifestyle (i.e. reduced habitual physical activity) plays a central role in ALL. Several considerations suggest that ALL might be a useful model of the pre-obese state: lifestyle is critical to development of obesity in ALL; ALL is relatively common; approximately 70 % of patients survive; patients are readily accessible during the 2 years of therapy and beyond.