Reliability and validity of rapid assessment tools for measuring 24-hour movement behaviours in children aged 0-5 years: the Movement Behaviour Questionnaire Baby (MBQ-B) and child (MBQ-C).

BACKGROUND: The development of validated "fit-for-purpose" rapid assessment tools to measure 24-hour movement behaviours in children aged 0-5 years is a research priority. This study evaluated the test-retest reliability and concurrent validity of the open-ended and closed-ended versions of the Movement Behaviour Questionnaire for baby (MBQ-B) and child (MBQ-C). METHODS: 300 parent-child dyads completed the 10-day study protocol (MBQ-B: N = 85; MBQ-C: N = 215). To assess validity, children wore an accelerometer on the non-dominant wrist (ActiGraph GT3X+) for 7 days and parents completed 2 × 24-hour time use diaries (TUDs) recording screen time and sleep on two separate days. For babies (i.e., not yet walking), parents completed 2 × 24-hour TUDs recording tummy time, active play, restrained time, screen time, and sleep on days 2 and 5 of the 7-day monitoring period. To assess test-retest reliability, parents were randomised to complete either the open- or closed-ended versions of the MBQ on day 7 and on day 10. Test-retest intraclass correlation coefficients (ICC's) were calculated using generalized linear mixed models and validity was assessed via Spearman correlations. RESULTS: Test-retest reliability for the MBQ-B was good to excellent with ICC's ranging from 0.80 to 0.94 and 0.71-0.93 for the open- and closed-ended versions, respectively. For both versions, significant positive correlations were observed between 24-hour diary and MBQ-B reported tummy time, active play, restrained time, screen time, and sleep (rho = 0.39-0.87). Test-retest reliability for the MBQ-C was moderate to excellent with ICC's ranging from 0.68 to 0.98 and 0.44-0.97 for the open- and closed-ended versions, respectively. For both the open- and closed-ended versions, significant positive correlations were observed between 24-hour diary and MBQ-C reported screen time and sleep (rho = 0.44-0.86); and between MBQ-C reported and device-measured time in total activity and energetic play (rho = 0.27-0.42). CONCLUSIONS: The MBQ-B and MBQ-C are valid and reliable rapid assessment tools for assessing 24-hour movement behaviours in infants, toddlers, and pre-schoolers. Both the open- and closed-ended versions of the MBQ are suitable for research conducted for policy and practice purposes, including the evaluation of scaled-up early obesity prevention programs.

A great way to bring up health behaviour topics at playgroup: a qualitative evaluation of the Healthy Conversations @ Playgroup program.

BACKGROUND: The early years is a critical stage to establish optimal nutrition and movement behaviours. Community playgroups are a relaxed environment for parents with a focus on social connection and supporting parents in their role as 'First Teachers'. Playgroups are therefore an opportunistic setting to promote health behaviours in the early years. To support parents with young children around healthy lifestyle behaviours, the Healthy Conversations @ Playgroup program was delivered in urban and regional areas, across three Australian jurisdictions between 2021-2023. OBJECTIVE: This qualitative evaluation aimed to understand how the Healthy Conversations @ Playgroup program was experienced by parents, playgroup coordinators and peer facilitators. DESIGN: Semi-structured virtual interviews and focus groups were conducted with parents, playgroup coordinators (i.e., person responsible for coordinating the playgroup) and peer facilitators (i.e., trained facilitator for the program) that participated in the Healthy Conversations @ Playgroup study. Transcripts were analysed following a thematic analysis approach. RESULTS: Twenty-eight playgroup parents, coordinators or peer facilitators participated in one of 8 focus groups or 5 interviews. Four themes were developed: Program strengths and challenges; Setting strengths and challenges; Factors that impact program delivery; Participant's suggestions for future program delivery. CONCLUSIONS: The Healthy Conversations @ Playgroup program was valued by parents, providing validation and normalisation of parenting practices, and fostering a shared experience of parenting. Playgroups are a convenient setting for families to attend. The dynamic and distracting nature of the playgroup setting were carefully considered when designing the program. Strategies to further enhance program engagement could include use of coordinator or parent champions, tailored delivery, and extending the reach to other family members. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12621000055808, registered 22 January 2021, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=380890.

Goal-directed therapeutic exercise for paediatric posterior fossa brain tumour survivors: a qualitative analysis of experiences.

PURPOSE: To explore child and parent experiences of a 12-week goal-directed therapeutic exercise intervention in paediatric posterior fossa brain tumours survivors and to identify features of the program that influenced program adherence and acceptability. METHODS: Eleven interviews were conducted; five parent-child dyads (mothers = 83%) and one parent only (mean child age = 10.6 ± 3.0 years; 83% male). Posterior fossa brain tumour survivors, who participated in a weekly goal-directed exercise program for 12 weeks, completed semi-structured interviews to discuss their experience of the program. An inductive content analysis was undertaken. Interviews were transcribed, imported into NVivo and independently coded by two reviewers. Code and content categories were iteratively discussed and refined. RESULTS: Five content categories were generated: (1) perceived improvements, (2) program logistics, (3) activity selection, (4) connection with the therapist and (5) options for technology. All participants valued the tailored exercise program and described improvements in movement competence. Children and their parents discussed preferring home- and community-based locations and favoured face-to-face delivery. Occasionally, parents reported difficulty completing the home program due to low child motivation or family time restrictions. Multiple families suggested an interactive digital application would be an effective delivery channel for the supplemental home-based program. CONCLUSION: A goal-directed exercise program delivered at home and in community-based locations was considered valuable and helpful for improving movement competence in paediatric survivors of posterior fossa brain tumour. TRIAL REGISTRATION: ACTRN12619000841178 June 12, 2019.

Cognitive Testing of Items Measuring Movement Behaviours in Young Children Aged Zero to Five Years: Development of the Movement Behaviour Questionnaires for -Baby (MBQ-B) and -Child (MBQ-C).

This paper describes the cognitive interview phase of the development of two brief surveys, the Movement Behaviour Questionnaire-Baby (MBQ-B) and Movement Behaviour Questionnaire-Child (MBQ-C), which measure the duration of physical activity, screen time, and sleep of children aged 0-5 years. The aims were (1) review the format, content, and clarity of questionnaire items and response options, (2) understand how parents retrieve, encode, and formulate responses when asked about their child's movement behaviours, and (3) identify potential sources of response error and make appropriate modifications. Interviews with parents of children aged 0-5 years were conducted using concurrent think-aloud techniques and probing questions. Parents reviewed the MBQ-B and/or MBQ-C depending on the developmental stage of their child(ren). Twenty-nine interviews were conducted with 20 parents, over four iterative rounds. Participants recalled usual family routines and rules when estimating the duration/frequency of behaviours. To estimate active play, parents referred to the child's daily routine considering wake and bedtimes, naps, and mealtimes. Participants were influenced by the examples provided, being unable to interpret these as exemplars only. Decomposing general items into specific questions with examples was well received. Use of numeracy skills when estimating duration was evident. Interviews informed revisions to item wording, examples, and recall prompts, which will be taken forward into the MBQ-B and MBQ-C validation studies. Utilising cognitive interviewing can enhance confidence that questionnaire items are correctly interpreted and understood by participants.

Altered bone and body composition in children and adolescents with confirmed prenatal alcohol exposure.

Prenatal alcohol exposure can contribute to long term adverse health outcomes. Development of the skeletal system begins at the early embryonic stage and continues into early adulthood but the effect of prenatal alcohol exposure on skeletal growth is relatively unexplored in a clinical population. Here, we performed dual X-ray absorptiometry to examine bone, fat, and muscle accrual in children and adolescents diagnosed with, or at risk of, fetal alcohol spectrum disorders (FASDs). Children (aged 4-9 years) with FASD or at risk of FASD (n = 10) had similar growth to age matched controls (n = 27). By adolescence (aged ≥10 years), those with FASDs (n = 13) were shorter and had lower areal bone mineral density and lean tissue mass than typically developing peers (n = 29). Overall, adolescents diagnosed with FASDs had greater odds of impairments to bone and body composition. These findings highlight the importance of early FASD diagnosis and appropriate post-diagnostic medical follow-up to enable timely, effective interventions to optimize bone and body composition during paediatric growth.

Evaluation of Wrist Accelerometer Cut-Points for Classifying Physical Activity Intensity in Youth.

Background: Wrist worn accelerometers are convenient to wear and provide greater compliance. However, methods to transform the resultant output into predictions of physical activity (PA) intensity have been slow to evolve, with most investigators continuing the practice of applying intensity-based thresholds or cut-points. The current study evaluated the classification accuracy of seven sets of previously published youth-specific cut-points for wrist worn ActiGraph accelerometer data. Methods: Eighteen children and adolescents [mean age (± SD) 14.6 ± 2.4 years, 10 boys, 8 girls] completed 12 standardized activity trials. During each trial, participants wore an ActiGraph GT3X+ tri-axial accelerometer on the wrist and energy expenditure (Youth METs) was measured directly using the Oxycon Mobile portable calorimetry system. Seven previously published sets of ActiGraph cut-points were evaluated: Crouter regression vertical axis, Crouter regression vector magnitude, Crouter ROC curve vertical axis, Crouter ROC curve vector magnitude, Chandler ROC curve vertical axis, Chandler ROC curve vector magnitude, and Hildebrand ENMO. Classification accuracy was evaluated via weighted Kappa. Confusion matrices were generated to summarize classification accuracy and identify patterns of misclassification. Results: The cut-points exhibited only moderate agreement with directly measured PA intensity, with Kappa ranging from 0.45 to 0.58. Although the cut-points classified sedentary behavior accurately (> 95%), classification accuracy for the light (3-51%), moderate (12-45%), and vigorous-intensity trials (30-88%) was generally poor. All cut-points underestimated the true intensity of the walking trials, with error rates ranging from 35 to 100%, while the intensity of activity trials requiring significant upper body and/or arm movements was consistently overestimated. The Hildebrand cut-points which serve as the default option in the popular GGIR software package misclassified 30% of the light intensity trials as sedentary and underestimated the intensity of moderate and vigorous intensity trials 75% of the time. Conclusion: Published ActiGraph cut-points for the wrist, developed specifically for school-aged youth, do not provide acceptable classification accuracy for estimating daily time spent in light, moderate, and vigorous intensity physical activity. The development and deployment of more robust accelerometer data reduction methods such as functional data analysis and machine learning approaches continues to be a research priority.

Bronchiectasis - Exercise as Therapy (BREATH): rationale and study protocol for a multi-center randomized controlled trial.

BACKGROUND: Globally, bronchiectasis (BE) unrelated to cystic fibrosis (CF) is recognized as a major cause of respiratory morbidity, mortality, and healthcare utilization. Children with BE regularly experience exacerbations of their condition resulting in frequent hospitalizations and decreased health-related quality of life (HR-QoL). Guidelines for the treatment and management of BE call for regular exercise as a means of improving aerobic fitness and HR-QoL. Moreover, research in adults with BE has shown that exercise can reduce the frequency of exacerbations, a potent predictor of future lung function decline and respiratory morbidity. Yet, to date, the health benefits resulting from therapeutic exercise have not been investigated in children with BE. The BREATH, Bronchiectasis - Exercise as Therapy, trial will test the efficacy of a novel 8-week, play-based therapeutic exercise program to reduce the frequency of acute exacerbations over 12 months in children with BE (aged ≥ 4 and < 13 years). Secondary aims are to determine the cost-effectiveness of the intervention and assess the program's impact on aerobic fitness, fundamental movement skill (FMS) proficiency, habitual physical activity, HR-QoL, and lung function. METHODS: This multi-center, observer-blinded, parallel-group (1:1 allocation), randomized controlled trial (RCT) will be conducted at three sites. One hundred and seventy-four children ≥ 4 and < 13 years of age with BE will be randomized to a developmentally appropriate, play-based therapeutic exercise program (eight, 60-min weekly sessions, supplemented by a home-based program) or usual care. After completing the baseline assessments, the number of exacerbations and secondary outcomes will be assessed immediately post-intervention, after 6 months of follow-up, and after 12 months of follow-up. Monthly, parental contact and medical review will document acute respiratory exacerbations and parameters for cost-effectiveness outcomes. DISCUSSION: The BREATH trial is the first fully powered RCT to test the effects of a therapeutic exercise on exacerbation frequency, fitness, movement competence, and HR-QoL in children with bronchiectasis. By implementing a developmentally appropriate, play-based exercise program tailored to the individual needs of children with bronchiectasis, the results have the potential for a major paradigm shift in the way in which therapeutic exercise is prescribed and implemented in children with chronic respiratory conditions. The exercise program can be readily translated. It does not require expensive equipment and can be delivered in a variety of settings, including the participant's home. The program has strong potential for translation to other pediatric patient groups with similar needs for exercise therapy, including those with obesity, childhood cancers, and neurological conditions such as cerebral palsy. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Register (ANZCTR) ACTRN12619001008112.

Physical ACTivity in Survivorship (PACTS): study protocol for a randomized controlled trial evaluating a goal-directed therapeutic exercise program in pediatric posterior fossa brain tumor survivors.

BACKGROUND: Posterior fossa brain tumors (PFBT) are the most common solid tumor in children. Recent increases in survival rates are encouraging; however, survivors may experience a plethora of disease- and treatment-related complications that can persist into adulthood. Therapeutic exercise interventions have been shown to improve quality of survivorship in other pediatric cancer diagnoses. There is also evidence that goal-directed interventions are effective at improving motor activities, function, and self-care in children with complex health conditions. Yet, there is currently no evidence on the efficacy of goal-directed therapeutic exercise in pediatric PFBT survivors. The Physical ACTivity in Survivorship (PACTS) study aims to investigate the effects of a novel goal-directed therapeutic exercise program on cardiorespiratory fitness and physical activity-related goal attainment in pediatric survivors of PFBT. METHOD: PFBT survivors, aged five to 17 years, who underwent surgery at least 12 months earlier and completed radiation therapy and/or chemotherapy at least 6 months prior will be recruited from the Queensland Children's Hospital (Brisbane, Australia) (target n = 48). Following baseline assessment, participants are randomized into either the intervention or usual care group. The intervention group will receive weekly individualized, goal-directed exercise therapy delivered face-to-face for 12 weeks, along with an accompanying home-based program (three sessions per week). Outcomes will be assessed at baseline, immediately post-intervention, and at 6- and 12-months post-intervention. The primary outcomes are cardiorespiratory fitness (Peak VO2) and physical activity-related goal attainment. Secondary outcomes are cardiorespiratory endurance, high-level mobility skills, functional muscle strength, habitual physical activity, gait, balance, quality of life, fatigue, participation, perceived movement skill competence and parameters of body composition. DISCUSSION: PACTS is the first study to investigate the efficacy of goal-directed therapeutic exercise in children with PFBT and provide evidence needed to inform clinical practice recommendations for managing quality of survivorship in PFBT survivors. TRIAL REGISTRATION: ACTRN12619000841178 .

Effectiveness of a novel digital application to promote fundamental movement skills in 3- to 6-year-old children: A randomized controlled trial.

OBJECTIVE: Fundamental movement skills (FMS) are the foundational building blocks for lifetime participation in physical activity (PA). Programmes to promote FMS development have been primarily delivered in childcare settings. No studies have evaluated the effectiveness of an interactive digital application, designed to be co-used by parent and child, to increase FMS proficiency in preschool-aged children. Therefore, the purpose of this study was to evaluate the effectiveness of the Moovosity™ programme, a novel digital application to increase FMS proficiency in 3- to 6-year-old children. Methods: A randomized controlled trial (RCT) was conducted involving 34 parent-child dyads randomly assigned to either the 8-week intervention (n = 17) or wait-list control (n = 17) condition. FMS proficiency, PA, and parental support for PA was assessed at baseline and 8-weeks. Intervention participants were given free access to the app over a period of 8 weeks. Wait-listed controls were given access after the 8-week period. Group differences for pre to post changes in outcomes were tested for significance using general linear mixed models. Results: There was a significant group by time interaction for object control skills (F1,32 = 10.81, P = 0.003). Intervention children exhibited significant improvements in object control skills, while children in the wait-list control group exhibited a modest decline. Intervention children also exhibited improvements in locomotor skills, while wait-listed controls exhibited minimal change; however, the group by time interaction fell outside the 0.05 level of significance (F1,32 = 3.15, P = 0.09). There were no significant intervention effects observed for child PA (F1,32 = 0.03, P = 0.86) and parental support for PA (F1,32 = 0.84, P = 0.37). Conclusions: An 8-week exposure to a digital application to promote motor competence within a family environment was effective in improving FMS proficiency in preschool-aged children. The results warrant further investigation in larger trials.

Living well after breast cancer randomized controlled trial protocol: evaluating a telephone-delivered weight loss intervention versus usual care in women following treatment for breast cancer.

BACKGROUND: Obesity, physical inactivity and poor diet quality have been associated with increased risk of breast cancer-specific and all-cause mortality as well as treatment-related side-effects in breast cancer survivors. Weight loss intervention trials in breast cancer survivors have shown that weight loss is safe and achievable; however, few studies have examined the benefits of such interventions on a broad range of outcomes and few have examined factors important to translation (e.g. feasible delivery method for scaling up, assessment of sustained changes, cost-effectiveness). The Living Well after Breast Cancer randomized controlled trial aims to evaluate a 12-month telephone-delivered weight loss intervention (versus usual care) on weight change and a range of secondary outcomes including cost-effectiveness. METHODS/DESIGN: Women (18-75 years; body mass index 25-45 kg/m2) diagnosed with stage I-III breast cancer in the previous 2 years are recruited from public and private hospitals and through the state-based cancer registry (target n = 156). Following baseline assessment, participants are randomized 1:1 to either a 12-month telephone-delivered weight loss intervention (targeting diet and physical activity) or usual care. Data are collected at baseline, 6-months (mid-intervention), 12-months (end-of-intervention) and 18-months (maintenance). The primary outcome is change in weight at 12-months. Secondary outcomes are changes in body composition, bone mineral density, cardio-metabolic and cancer-related biomarkers, metabolic health and chronic disease risk, physical function, patient-reported outcomes (quality of life, fatigue, menopausal symptoms, body image, fear of cancer recurrence) and behaviors (dietary intake, physical activity, sitting time). Data collected at 18-months will be used to assess whether outcomes achieved at end-of-intervention are sustained six months after intervention completion. Cost-effectiveness will be assessed, as will mediators and moderators of intervention effects. DISCUSSION: This trial will provide evidence needed to inform the wide-scale provision of weight loss, physical activity and dietary interventions as part of routine survivorship care for breast cancer survivors. TRIAL REGISTRATION: Australian and New Zealand Clinical Trial Registry (ANZCTR) - ACTRN12612000997853 (Registered 18 September 2012).

ABCD: Anthropometry, Body Composition, and Crohn Disease.

BACKGROUND: Young individuals with Crohn disease (CD) are at risk of poor bone mineral density (BMD) and reduced lean tissue mass (LTM). The importance of LTM for maintaining skeletal health, in both incident and established CD, is evidenced. We used dual-energy x-ray absorptiometry assessment to identify areal BMD and LTM in individuals with CD. METHODS: In 57 patients with CD (15F; 12.99-14.16 years) anthropometric, disease activity, bone age assessment, and total body dual-energy x-ray absorptiometry measurements were acquired. A 4-step algorithm was used to assess simultaneous bone and body composition data: areal BMD and height z scores, and LTM for height and bone mineral content (BMC) for LTM z scores were calculated. Low z score cut-off values were defined as ≤1 standard deviations below the population means. RESULTS: The CD cohort showed: low areal BMD z scores (P = 0.00); and low LTM for height (P = 0.00) according to defined cut-off values. BMC appeared to be adapting for the lower amount of LTM. Correcting for bone age eliminated the low areal BMD z scores. As expected, LTM for height and BMC for LTM z scores remained unchanged. CONCLUSIONS: We present a useful clinical algorithm to show significant LTM for height deficits, regardless of chronological or bone age, in this CD cohort. BMC seemed to adapt to the reduced LTM, indicating clinically "normal" areal BMD for age when considered for height. The ongoing deficits in LTM may, however, create chronic long-term consequences for bone health. Improving LTM should be a focus of clinical treatment in individuals with CD.

Cystic fibrosis-related bone disease in children: Examination of peripheral quantitative computed tomography (pQCT) data.

BACKGROUND: The investigation of skeletal health data beyond dual X-ray absorptiometry (DXA) is limited in young individuals with CF. We assessed volumetric bone mineral densities (BMD), and bone and muscle parameters using peripheral quantitative computed tomography (pQCT) in individuals with CF and controls, 7.00-17.99 years. METHODS: Peripheral QCT (XCT 3000, Stratec) measurements were made in 53 individuals with CF and 53 controls. Bone mineral content (BMC), total volumetric BMD (vBMD) and cross sectional area (CSA) of the bone were measured at the 4% and 66% sites of the non-dominant tibia and radius. Additionally, trabecular vBMD and bone strength index (BSIc) were measured at the 4% sites, and cortical vBMD, muscle CSA (mCSA) and strength strain index (SSI) were measured at the 66% sites. RESULTS: Pre-pubertal males with CF had greater trabecular vBMD (p=0.01) and total vBMD (p=0.00) at 4% tibia, and greater total vBMD (p=0.02) at 4% radius. Pre-pubertal females with CF had greater total vBMD at 66% tibia (p=0.02) and radius (p=0.04), and cortical vBMD (p=0.04) at the radius. At puberty, the CF cohort had less BMC at 4% tibia (males, p=0.02; females, p=0.01), and smaller mCSA at 66% tibia (males, p=0.02; females, p=0.01). Pubertal CF females had a smaller bone CSA (p=0.01) at 4% tibia, and lower bone strength (SSI) at the tibia (p=0.00) and radius (p=0.05) sites. CONCLUSIONS: Bone strength parameters were not compromised prior to puberty in this CF cohort. At puberty, the bone phenotype changed for this CF cohort, showing several deficits compared to the controls. However, bone strength was adapting to the mechanical demands of the muscle. Altered bone parameters and their implications for lowered bone strength with increased age may be greatly influenced by: the CF cohort remaining smaller for age and/or a reduced bone strain, secondary to reduced muscle force.

Cystic fibrosis-related bone disease explored using a four step algorithm.

BACKGROUND: A suboptimal bone accrual in young individuals with cystic fibrosis (CF) may be related to the development of a premature CF-related bone disease. Dual energy X-ray absorptiometry (DXA) is the mainstream measure of bone health; however, the influence of body size and lean tissue mass (LTM) on bone data is poorly interpreted. METHODS: Total body dual-energy X-ray absorptiometry (DXA) measurements of bone mineral content (BMC) and LTM in 53 individuals with CF (7.00-17.99years) were compared to 53 sex-matched controls. BMC, height, and LTM in relation to height and BMC Z-scores were calculated and used in a 4-step algorithm. RESULTS: Pubertal females with CF had less total body BMC for age (p=0.02); pre-pubertal males (p=0.05) and pubertal females with CF (p=0.03) were shorter; and pubertal females with CF showed less total body BMC for LTM (p=0.01). CONCLUSIONS: The algorithm showed the following: (1) prior to puberty lowered total body BMC was primarily due to short stature, (2) LTM was appropriate for body size, and (3) pubertal females with CF had significantly less total body BMC for their LTM. Longer controlled trials are needed to clinically interpret CF-related bone disease using DXA derived data that considers patient size and body composition.

Bones in pediatric Crohn's disease: a review of fracture risk in children and adults.

There is evidence to suggest that the inflammation associated with Crohn's disease (CD) impacts the bone health of patients, predisposing them to early onset osteoporosis and increasing their risk of fracture. Fractures have been documented in patients with CD, with a high proportion of these being found during young adulthood, which suggests that these patients are not simply fracturing as a result of the normal aging process but rather due to the presence of CD. In population terms, patients with CD have increased risk of fracture compared with the general population. Studies in children suggest that, irrespective of time on corticosteroid therapy, the underlying systemic inflammation associated with CD is an independent detrimental influence on the bone health of children with CD. This poses the question as to whether the onset of disease in childhood predisposes the individual to increased risk of future fractures later in life, as a result of decreased peak bone mass during the growing years. It is generally believed that dual energy x-ray absorptiometry-assessed areal bone mineral density is a good indicator of fracture risk; however, several studies have shown this may not be the case. New research, utilizing peripheral quantitative computed tomography, which provides a true volumetric assessment of bone, suggests altered bone geometry in patients with CD, which poses a structural threat by being more brittle and susceptible to damage accumulation.

Bone health in children with inflammatory bowel disease: adjusting for bone age.

OBJECTIVES: Clinical results of bone mineral density for children with inflammatory bowel disease are commonly reported using reference data for chronological age. It is known that these children, particularly those with Crohn disease, experience delayed growth and maturation. Therefore, it is more appropriate to compare clinical results with bone age rather than chronological age. MATERIALS AND METHODS: Areal bone mineral density (aBMD) was measured using dual energy x-ray absorptiometry, and bone age was assessed using the Tanner-Whitehouse 3 method from a standard hand/wrist radiograph. Results were available for 44 children ages 7.99 to 16.89 years. Areal bone mineral density measurements were converted to z scores using both chronological and bone ages for each subject. RESULTS: Areal bone mineral density z scores calculated using bone age, as opposed to chronological age, were significantly improved for both the total body and lumbar spine regions of interest. When subjects were grouped according to diagnosis, bone age generated z scores remained significantly improved for those with Crohn disease but not for those diagnosed with ulcerative colitis. Grouping of children with Crohn disease into younger and older ages produced significantly higher z scores using bone age compared with chronological for the older age group, but not the younger age group. CONCLUSIONS: Our findings, in accordance with those presented in the literature, suggest that aBMD results in children with Crohn disease should include the consideration of bone age, rather than merely chronological age. Bone size, although not as easily available, would also be an important consideration for interpreting results in paediatric populations.