A. J. Murphy

Validity of BMI as a measure of obesity in Australian white Caucasian and Australian Sri Lankan children

Background: Body mass index (BMI) is used to diagnose obesity. However, its ability to predict the percentage fat mass (%FM) reliably is doubtful. Therefore validity of BMI as a diagnostic tool of obesity is questioned. Aim: This study is focused on determining the ability of BMI-based cut-off values in diagnosing obesity among Australian children of white Caucasian and Sri Lankan origin. Subjects and methods: Height and weight was measured and BMI (W/H2) calculated. Total body water was determined by deuterium dilution technique and fat free mass and hence fat mass derived using age- and gender-specific constants. A %FM of 30% for girls and 20% for boys was considered as the criterion cut-off level for obesity. BMI-based obesity cut-offs described by the International Obesity Task Force (IOTF), CDC/NCHS centile charts and BMI-Z were validated against the criterion method. Results: There were 96 white Caucasian and 42 Sri Lankan children. Of the white Caucasians, 19 (36%) girls and 29 (66%) boys, and of the Sri Lankans 7 (46%) girls and 16 (63%) boys, were obese based on %FM. The FM and BMI were closely associated in both Caucasians (r = 0.81, P<0.001) and Sri Lankans (r = 0.92, P<0.001). Percentage FM and BMI also had a lower but significant association. Obesity cut-off values recommended by IOTF failed to detect a single case of obesity in either group. However, NCHS and BMI-Z cut-offs detected cases of obesity with low sensitivity. Conclusions: BMI is a poor indicator of percentage fat and the commonly used cut-off values were not sensitive enough to detect cases of childhood obesity in this study. In order to improve the diagnosis of obesity, either BMI cut-off values should be revised to increase the sensitivity or the possibility of using other indirect methods of estimating the %FM should be explored.

Body composition of children with cancer

BACKGROUND Nutritional status, as represented by body composition, is an important consideration in the treatment of pediatric cancer patients because it is linked to poor outcomes. Little is known about how a childs body composition responds to cancer and treatment. OBJECTIVES We aimed to compare the body composition of children undergoing treatment of cancer with that of healthy controls and to compare body composition between children with hematologic malignancies and children with solid tumors. DESIGN This cross-sectional study measured height, weight, body cell mass, fat-free mass, and fat mass in 48 children undergoing treatment of cancer and blood-related disorders and in age-matched healthy controls. RESULTS Patients with cancer had a significantly lower body cell mass index z score (body cell mass/height raised to the power of 2.5 for females and 3 for males) than did controls (P = 0.0001), and 45% of the patients with cancer were considered malnourished according to body cell mass. Subjects with cancer had a significantly higher percentage of body fat (P = 0.0001) and fat mass (P = 0.0001) than did controls; however, there was no significant difference in fat-free mass (P = 0.09). On the basis of percentage fat, 77% of subjects with cancer were considered obese. No difference in body composition was observed between cancer types. CONCLUSIONS This study showed that children undergoing treatment of all types of cancer have a significantly lower body cell mass and a significantly higher fat mass than do healthy controls. Nutritional support is suggested for all children undergoing treatment of cancer.

Nutritional status and energy expenditure in children pre-bone-marrow-transplant.

Summary:The aims of this study were to establish the nutritional status of children pre-BMT and to determine whether predictive methods of assessing nutritional status and resting energy expenditure (REE) are accurate in this population. We analysed the body cell mass (BCM) (n=26) and REE (n=24) in children undergoing BMT. BCM was adjusted for height (BCM/HTp) and expressed as a Z score to represent nutritional status. To determine whether body mass index (BMI) was indicative of nutritional status in children undergoing BMT, BMI Z scores were compared to the reference method of BCM/HTp Z scores. Schofield predictive equations of basal metabolic rate (BMR) were compared to measured REE to evaluate the accuracy of the predictive equations. The mean BCM/HTp Z score for the subject population was −1.09±1.28. There was no significant relationship between BCM/HTp Z score and BMI Z score (r=0.34; P>0.05); however there was minimal difference between measured REE and predicted BMR (bias=−11±149 kcal/day). The results of this study demonstrate that children undergoing BMT may have suboptimal nutritional status and that BMI is not an accurate indication of nutritional status in this population. However, Schofield equations were found to be suitable for representing REE in children pre-BMT.

The validity of simple methods to detect poor nutritional status in paediatric oncology patients

Poor nutritional status is a major concern for children being treated for an oncology condition. It is vital for optimal prognosis that nutritional concerns are recognised and treated promptly. The majority of oncology treatment centres only use simple methods to screen for poor nutritional status; however, it is unknown whether these simple methods accurately recognise poor nutritional status. We aimed to determine whether commonly used simple nutritional assessment variables could accurately identify poor nutritional status in children being treated for oncological conditions. This cross-sectional study measured height, weight, mid-upper arm circumference, triceps skinfold, albumin levels and body cell mass in forty children being treated for an oncological condition. To determine whether commonly used nutritional variables were suitable determinants, the variables were compared against the reference measure of body cell mass index (BCMI) Z-scores. Using the BCMI Z-score cut-off of - 1.65, 48 % of the study population were considered poorly nourished. Correlational analysis showed that there was no significant biological relationship between the BCMI Z-score and the simple parameters. When divided into two groups based on the nutritional status indicated by the BCMI Z-score, the independent t tests between the well-nourished and malnourished groups demonstrated that there was a significant difference in the BMI Z-score (P = 0.01) between the groups. No simple nutritional measures were found to accurately identify poor nutritional status in children being treated for oncological conditions.

Survival in overweight and underweight children undergoing hematopoietic stem cell transplantation

Background/objectives:There is a growing body of evidence that nutritional status influences the morbidity and mortality of children undergoing treatment for cancer. The aim of this paper is to determine if nutritional status is associated with survival post-pediatric bone marrow transplant.Subjects/methods:This was a single-center retrospective audit of patients who underwent an autologous or allogeneic hematopoietic stem cell transplant. Patients were divided into three weight categories of underweight, ideal weight and overweight defined by percent ideal body weight. The outcome of interest, overall post transplant survival, was compared between weight categories.Results:Of 113 patients, 15 (13%) were underweight and 41 (36%) were classified as overweight. After adjustment for age, sex, donor source, conditioning therapy and year of transplant, overweight patients were significantly less likely to survive than ideal-weight patients (hazard ratio (HR) 1.91; 95% confidence interval, 1.10–3.31). There was no significant increase in mortality when underweight patients were compared with ideal-weight patients (HR 1.47; 95% confidence interval, 0.57–3.79).Conclusions:Children who are overweight before hematopoietic stem cell transplantation have decreased survival compared with ideal-weight children.

Body cell mass index in children: interpretation of total body potassium results

Body cell mass (BCM) is a valuable measure of functional nutritional status in children. As BCM is related to body size, it is essential that BCM is adjusted for stature when interpreting BCM data in children. Our aim was to examine the relationship between height and BCM in healthy children to determine the power by which height should be raised to adjust BCM for stature. This cross-sectional study calculated BCM by 40K counting in 146 healthy children aged between 5 and 18 years. The relationship between BCM and height was explored using log-log regression. The present results demonstrate that the power by which height should be raised to adjust for BCM in females is 2.39 (se 0.09) and for males is 2.92 (se 0.10). A simplified sex-specific version of the index, BCM/height2.5 for females and BCM/height3 for males, was found to be statistically valid and numerically convenient, with the proportion of variation that could be attributed to height being less than 2 %. The present study shows that there is a difference in the relationship between height and BCM for males and females and that BCM can be adjusted in children using the BCM index of BCM/height2.5 for females and BCM/height3 for males.

Validation of percent body fat indicators in pediatric oncology nutrition assessment.

Background Given the high prevalence of malnutrition and potential impact nutritional status can have on a child undergoing treatment for cancer, it is vital that oncology centers regularly assess nutritional status. It is important that simple noninvasive anthropometric nutrition assessment measures correlate to more accurate body composition measures. Objectives The aim of this study was to determine the relationship between anthropometric measures and percent body fat determined via air displacement plethysmography in the children being treated in a pediatric oncology and hematology department. Design This cross-sectional study measured height, weight, percent ideal body weight (%IBW), mid arm circumference, triceps skinfolds, and mid upper arm fat area in 23 children. These anthropometric variables were compared against the reference measure of percent body fat via air displacement plethysmography. Results Correlational analysis and general linear models showed that there was a significant statistical relationship between percent body fat and body mass index Z score, %IBW, mid arm circumference, triceps skinfolds, and arm fat area. Conclusions Simple anthropometric measurements of %IBW and triceps skinfolds are good indicators of percent body fat and should be incorporated into regular nutrition assessment of the pediatric oncology patient.

An international survey of nutritional practices in low- and middle-income countries: a report from the International Society of Pediatric Oncology (SIOP) PODC Nutrition Working Group

Background/Objectives:Optimal nutritional status is important in children with cancer, as it can influence clinical outcomes. To improve the nutritional health of children and adolescents receiving treatment for cancer residing in low income and middle-income countries (LMIC), we investigated nutrition practices among these nations’ institutions providing treatment for childhood cancer.Subject/Methods:A cross-sectional survey of nutrition practice was administered to staff members at institutions providing treatment for children with cancer between 2011 and 2012. Countries classified as low income and middle income were divided by geographical region. Final analysis was performed with 96 surveys, which included 27 institutions from Asia, 27 institutions from Latin America and Caribbean, 27 institutions from Africa and 15 institutions from Europe.Results:The study found that 55% of institutions had a dietician available on their service. Access to dieticians, lack of nutrition resources and lack of nutrition education of staff were the main barriers to providing nutrition care in LMIC. Half of the institutions performed nutritional assessment at diagnosis, and the methods used varied widely. Twenty-nine percent of all institutions used complementary and alternate therapies within their clinical practice, and 35% of institutions reported that nutrition education was provided to patients and families.Conclusions:Priority areas for improving the nutritional management in LMIC include the following: (1) improved nutrition education and assessment tools for doctors and nurses; (2) increased availability of nutrition education resources for families and patients; and (3) identification of the role of complementary and alternative therapies in closing gaps in symptom management in these institutions.

The use of air displacement plethysmography in children and adolescents with cystic fibrosis

Objectives: The purpose of this paper was to evaluate the use of air displacement plethysmography (ADP) in children and adolescents with cystic fibrosis (CF). Specifically, the primary aim of this study was to compare estimates of fat-free mass (FFM) measured from ADP and dual energy X-ray absorptiometry (DEXA) in children and adolescents with CF. The secondary aim was to compare the effect of using predicted thoracic gas volume (V TG) and measured V TG for the calculation of FFM by ADP in this population.Methods: Cross-sectional FFM measurements were taken using ADP and DEXA in 52 children and adolescents with CF, ranging in age from 6.3 to 16.6 y.Results: Bland–Altman analysis showed that ADP values of FFM were on average 0.59 kg higher than DEXA values (95% limits of agreement = 3.61 to −2.43 kg); however this difference was not significant. There was no significant correlation (r=−0.26, P=0.07) between the mean FFM and difference in FFM between ADP and DEXA. Using either predicted or measured V TG did not significantly affect FFM estimates in individuals with CF who had normal lung function (bias=−0.39±0.86 kg; r=−0.02, P=0.93).Conclusions: ADP is an appropriate technique for use in children and adolescents with CF.

The nutritional status of children with cystic fibrosis

The importance of nutritional intervention for children with cystic fibrosis (CF) is well recognised. It would be expected that the increase in knowledge over the past decade would be reflected in improvements in nutritional status for the CF paediatric population. The aim of the present paper was to evaluate the nutritional status of children with CF, cross-sectionally and longitudinally. Body cell mass adjusted for gender and size (BCM/Htp) was measured in sixty-four children with CF to represent nutritional status and expressed as a Z-score. The cross-sectional results showed a mean BCM/Htp Z-score of 0.54 (sd 1.21), with males having a slightly higher Z-score than females but with a larger variation. At the initial measurement, only one female and one male were considered sub-optimally nourished. The longitudinal analysis after 2 years showed that the mean population had a significantly decreased BCM/Htp Z-score; however, when each gender was analysed separately, this decrease was significant only in the males. At the final measurement, only two females and three males were considered sub-optimally nourished. It is evident from our results that children with CF are well nourished, with only a small percentage considered malnourished. It appears that nutritional status decreases with age, with this decline being more evident in males. These results signify that although children with CF are better nourished with current treatment support, intervention needs to continue throughout a CF patients life to counteract the changes that occur with age.