Impaired Physical Function Associated with Childhood Obesity: How Should We Intervene?

BACKGROUND: This study examined relationships between adiposity, physical functioning, and physical activity. METHODS: Obese (N = 107) and healthy-weight (N = 132) children aged 10-13 years underwent assessments of percent body fat (%BF, dual energy X-ray absorptiometry); knee extensor strength (KE, isokinetic dynamometry); cardiorespiratory fitness (CRF, peak oxygen uptake by cycle ergometry); physical health-related quality of life (HRQOL); and worst pain intensity and walking capacity [six-minute walk (6MWT)]. Structural equation modelling was used to assess relationships between variables. RESULTS: Moderate relationships were observed between %BF and (1) 6MWT, (2) KE strength corrected for mass, and (3) CRF relative to mass (r -0.36 to -0.69, p ≤ 0.007). Weak relationships were found between %BF and physical HRQOL (r -0.27, p = 0.008); CRF relative to mass and physical HRQOL (r -0.24, p = 0.003); physical activity and 6MWT (r 0.17, p = 0.004). Squared multiple correlations showed that 29.6% variance in physical HRQOL was explained by %BF, pain, and CRF relative to mass; while 28.0% variance in 6MWT was explained by %BF and physical activity. CONCLUSIONS: It appears that children with a higher body fat percentage have poorer KE strength, CRF, and overall physical functioning. Reducing percent fat appears to be the best target to improve functioning. However, a combined approach to intervention, targeting reductions in body fat percentage, reductions in pain, and improvements in physical activity and CRF may assist physical functioning.

Relationships between self-reported lifetime physical activity, estimates of current physical fitness, and aBMD in adult premenopausal women.

Osteoporosis is common, and physical activity is important in its prevention and treatment. Of the categories of historical physical activity (PA) examined, we found that weight-bearing and very hard physical activity had the strongest relationships with areal bone mineral density (aBMD) throughout growth and into adulthood, while for measures of strength, only grip strength proved to be an independent predictor of aBMD. PURPOSE/INTRODUCTION: To examine relationships between aBMD (total body, lumbar spine, proximal femur, tibial shaft, distal radius) and estimates of historical PA, current strength, and cardiovascular fitness in adult premenopausal women. METHODS: One hundred fifty-two adult premenopausal women (40 ± 9.6 years) undertook aBMD (dual-energy X-ray absorptiometry (DXA)) and completed surveys to estimate historical physical activity representative of three decades (Kriska et al. [1]), while subsets underwent functional tests of isokinetic strength (hamstrings and quadriceps), grip strength (hand dynamometer), and maximum oxygen uptake (MaxV02; cycle ergometer). Historical PA was characterized by demand (metabolic equivalents, PA > 3 METS; PA > 7 METS) and type (weight-bearing; high impact). RESULTS: Significant positive independent predictors varied by decade and site, with weight-bearing exercise and PA > 3 METS significant for the tibial shaft (10-19 decade) and only PA > 7 METS significant for the final two decades (20-29 and 30-39 years; total body and total hip). A significant negative correlation between high impact activity and tibial shaft aBMD appeared for the final decade. For strength measures, only grip strength was an independent predictor (total body, total hip), while MaxV02 provided a significant independent prediction for the tibial shaft. CONCLUSIONS: Past PA > 7 METS was positively associated with aBMD, and such activity should probably constitute a relatively high proportion of all weekly PA to positively affect aBMD. The findings warrant more detailed investigations in a prospective study, specifically also investigating the potentially negative effects of high impact PA on tibial aBMD.

Impact exercise and bone density in premenopausal women with below average bone density for age.

PURPOSE: To study the effects of two home-based impact exercise programs on areal bone mineral density (aBMD) in adult premenopausal women with below average aBMD for age (negative Z-scores; 40.8 years; n = 107). METHODS: Two unilateral impact exercise programs were employed, one targeting the total hip and lumbar spine (n = 42 pairs), the other the distal radius (n = 24 pairs) with some individuals performing both. Force plate data were used to establish exercise loading characteristics (peak loads, time to peak), dual-energy X-ray absorptiometry (DXA) provided bone data. Calcium intake, health and extraneous physical activity (PA) were determined by survey. Exercise for both hip and spine consisted of unilateral landings from adjustable steps (maximum height 63.5 cm) while impacts were delivered to the forearm by arresting falls against a wall. An exercise log was used to provide the exercise prescription, record each exercise bout and any injuries. Participants were randomly assigned to exercise or control groups and pair-matched (age, BMI, Z-score, aBMD). Compliance was calculated as the number of sessions completed divided by the total prescribed number (mean ~50 %). RESULTS: The programs delivered significant gains pre to post at each site compared with significant losses in controls (forearm: 3.9 vs -3.9 %; total hip: 2.0 vs -2.6 %; lumbar spine: 2.8 vs -2.9 % exercise and controls, respectively, all p < 0.001). No exerciser lost bone at the target site regardless of compliance which was strongly correlated with bone gains (R (2) = 0.53-0.68, all p < 0.001). CONCLUSIONS: Impact exercise provides an effective means of improving below average aBMD without supervision in this at risk population.

Musculoskeletal pain in obese compared with healthy-weight children.

OBJECTIVES: To investigate whether obesity is associated with musculoskeletal pain in children. MATERIALS AND METHODS: Obese (n=107) and healthy-weight (n=132) 10- to 13-year-old children (132 males, 107 females) participated in an observational case-control study. Children self-reported pain location (excluding abdominal pain), pain intensity (current and prior week), and pain prevalence (overall and lower limb) using the Pediatric Pain Questionnaire. Body composition was assessed (dual-energy x-ray absorptiometry) and children wore an accelerometer for 8 days. RESULTS: After adjustment for accelerometry (weekly average counts per hour) and socioeconomic status, obese children had more intense pain (worst pain, P=0.006), pain in more locations (P≤0.005), and a higher prevalence of lower limb pain (60% vs. 52% respectively, P=0.012) than healthy-weight children. Significant relationships were observed between body mass index and total pain locations (P≤0.004, unadjusted and adjusted) and worst pain intensity (P≤0.009, adjusted for socioeconomic status/accelerometry). There were no significant relationships between percent body fat and pain variables (unadjusted/adjusted analyses, P=0.262 to 1.0). DISCUSSION: Obesity in children was associated with increased overall and lower limb musculoskeletal pain, for which body mass index was a stronger predictor than adiposity. Clinicians treating obese children should screen for pain and prescribe exercise programs that take their symptoms into account.

Physiological and behavioural outcomes of a randomised controlled trial of a cognitive behavioural lifestyle intervention for overweight and obese adolescents.

AIM: This study evaluates the efficacy of the Choose Health program, a family-based cognitive behavioural lifestyle program targeting improved eating and activity habits, in improving body composition, cardiovascular fitness, eating and activity behaviours in overweight and obese adolescents. METHOD: The sample comprised 29 male and 34 female overweight (n = 15) or obese (n = 48) adolescents aged 11.5-18.9 years (M = 14.3, SD = 1.9). Participants were randomly allocated to treatment or waitlist control conditions; waitlist condition participants were offered treatment after 6 months. DEXA-derived and anthropometric measures of body composition; laboratory-based cycle ergometer and field-assessed cardiovascular fitness data; objective and self-report physical activity measures; and self-report measures of eating habits and 7-day weighed food diaries were used to assess treatment outcome. Adherence to treatment protocols was high. RESULTS: Treatment resulted in significant (p < .05) and sustained improvements in a range of body composition (body fat, percent body fat, lean mass) and anthropometric measures (weight, BMI, BMI-for-age z-score and percentiles). Minimal improvements were seen in cardiovascular fitness. Similar results were obtained in completer and intention-to-treat analysis. Poor adherence to assessment protocols limits conclusions that can be drawn from physical activity and dietary data. CONCLUSIONS: Participation in the Choose Health program resulted in significant improvement in body composition. Longer-term follow up is required to determine the durability of intervention effects. Alternative approaches to the measurement of diet and physical activity may be required for adolescents.

Knee extensor strength differences in obese and healthy-weight 10-to 13-year-olds.

The purpose of this study was to investigate if obese children have reduced knee extensor (KE) strength and to explore the relationship between adiposity and KE strength. An observational case-control study was conducted in three Australian states, recruiting obese [N = 107 (51 female, 56 male)] and healthy-weight [N = 132 (56 female, 76 male)] 10- to 13-year-old children. Body mass index, body composition (dual energy X-ray absorptiometry), isokinetic/isometric peak KE torques (dynamometry) and physical activity (accelerometry) were assessed. Results revealed that compared with their healthy-weight peers, obese children had higher absolute KE torques (P ≤ 0.005), equivocal KE torques when allometrically normalized for fat-free mass (FFM) (P ≥ 0.448) but lower relative KE torques when allometrically normalized for body mass (P ≤ 0.008). Adjustments for maternal education, income and accelerometry had little impact on group differences, except for isometric KE torques relative to body mass which were no longer significantly lower in obese children (P ≥ 0.013, not significant after controlling for multiple comparisons). Percent body fat was inversely related to KE torques relative to body mass (r = -0.22 to -0.35, P ≤ 0.002), irrespective of maternal education, income or accelerometry. In conclusion, while obese children have higher absolute KE strength and FFM, they have less functional KE strength (relative to mass) available for weight-bearing activities than healthy-weight children. The finding that FFM-normalized KE torques did not differ suggests that the intrinsic contractile properties of the KE muscles are unaffected by obesity. Future research is needed to see if deficits in KE strength relative to mass translate into functional limitations in weight-bearing activities.

Does long-term swimming participation have a deleterious effect on the adult female skeleton?

Swimming is a popular activity for Australian women with proven cardiovascular benefits yet lacks the features thought necessary to stimulate positive adaptive changes in bone. Given that peak bone mass is attained close to the end of the second decade, we asked whether swimming was negatively associated with bone mineral density in premenopausal women beyond this age. Bone mass and retrospective physical activity data were gathered from 43 female swimmers and 44 controls (mean ages 40.4 and 43.8 years, respectively). Swimmers were recruited from the Australian Union of Senior Swimmers International while controls were healthy community dwellers with similar lean mass, fat mass, height, weight and body mass index. None of the participants had a history of medical complaints nor use of medications known to affect bone. Dual energy X-ray absorptiometry was used to determine areal bone mineral density at total body, lumbar spine, proximal femur, distal radius and tibia while self-administered questionnaires were used to approximate historical and recent physical activity and calcium intake. Swimmers had averaged over 2 hours of swimming per week for the past 5 years and 1.45 h/week over lifetime with no systematic swimming exposure for controls. Lifetime exposure to weight bearing and impact exercise were similar. There were no intergroup differences for bone mass at any site though controls had higher incidence of low bone mass/osteoporosis. No differences in bone mass were detected between swimmers in the upper and lower quartiles for swim participation for any period. Long-term swim participation did not compromise areal bone mineral density.

Parent- and adolescent-reported barriers to participation in an adolescent overweight and obesity intervention.

This study explored reported barriers to treatment completion in a sample of adolescents and their parents who either completed or did not complete family-based cognitive behavioral lifestyle intervention for overweight and obese adolescents. The sample comprises 56 overweight or obese adolescents (52% female) aged 11.5-18.9 years (mean = 14.5, s.d. = 1.8) and a parent. 57% of families did not complete treatment and maintenance phases of the intervention. A telephone-administered questionnaire assessing barriers to participation was completed by 96% of adolescents and 91% of parent completers and 100% of adolescents and 94% of parent noncompleters. Adolescents and parents most commonly reported barriers to participation related to research demands, treatment approach, program components/strategies, practical barriers, and other individual/family demands. Parents also noted adolescent effort, parent-adolescent conflict, and adolescent unhappiness as barriers to participation. While both completers and noncompleters experienced barriers to participation, families who discontinued treatment reported experiencing more treatment barriers. Findings of the current study suggest that adolescents and parents may find it easier to participate in adolescent overweight and obesity interventions if research and out-of-session program demands are minimized, efforts are made to enhance adolescent motivation, and treatment is offered in a convenient location and scheduled around school holidays and other family demands. Results also suggest that targeting adolescent unhappiness, family stressors, and parent-adolescent conflict in treatment may improve retention. Future research should explore the impact of these modifications on treatment completion and outcomes.

An initial evaluation of a long-term, sustainable, integrated community-based physical activity program for adults with intellectual disability.

BACKGROUND: Physical activity (PA) programs for adults with intellectual disability (ID) have positive impacts, at least in the short term. No research has been reported on the effect of long-term engagement in PA programs for adults with ID. This paper explores the physical and psychosocial benefits gained by two individuals with mild ID who participated in a long-term PA program. METHOD: Accelerometery was used to collect PA data during the program and for 7-day periods outside of the program. To explore the psychosocial outcomes gained from participating in the program, participants and their caregivers were interviewed about their participation experiences. RESULTS: Across time, a decrease in the amount of light activity engaged in during sessions was found, with participants gradually increasing their moderate to vigorous activity. Psychosocial benefits, including meeting new people and gaining social acknowledgement were reported by participants and caregivers. CONCLUSIONS: Long-term, sustainable, low cost PA programs (such as the one under investigation) can minimise barriers to physical activity for people with ID.

Predicting treatment initiation in a family-based adolescent overweight and obesity intervention.

Little is known about factors associated with treatment initiation in overweight and obese adolescents. This study investigated parent-reported adolescent demographic, adolescent health, and parent motivation factors associated with initiation of a family-based adolescent overweight and obesity intervention. A telephone survey was completed by 349 parents calling to register their interest in participating in a cognitive behavioral lifestyle intervention for adolescent overweight and obesity. A total of 172 families (49.3%) returned their consent form to initiate treatment. A binomial logistic regression, with predictors entered in three blocks: (i) adolescent demographic (adolescent age, gender, adolescent BMI-for-age z-score, parent BMI); (ii) adolescent health (perceived adolescent physical and mental health, presence of an adolescent physical health problem or mental health problem, medication intake); and (iii) parent motivation (perceived adolescent weight category, concern about adolescent weight, importance of adolescent weight, confidence in adolescent capacity to change weight, priority of adolescent weight loss, discrepancy between adolescent current and ideal weight, previous weight loss attempts), was significant (χ2 (16) = 35.19, P = 0.004) accounting for 12.4-16.5% (95% confidence interval) of treatment initiation variance. Parent-reported adolescent physical health problem, parent perception of adolescent weight category, parent priority of adolescent weight loss, and parent perception of discrepancy between adolescent current and ideal weight were significant in the model. These findings indicate that data collected at intake are associated with treatment initiation and highlight the role of assessing and enhancing treatment motivation from initial contact.

Energy expended by adults with and without intellectual disabilities during activities of daily living.

The aims of this study were to (1) determine the energy expenditure of adults with and without intellectual disabilities during common activities of daily living (ADL), (2) use these values to evaluate the accuracy of equivalent activity values reported in the Compendium of Physical Activities (CPA), and (3) identify ADL that may confer a health benefit for adults with intellectual disabilities when undertaken regularly. Energy expenditure was measured for adults with intellectual disabilities (N=31; 29.0±8.6 yr) and adults without intellectual disabilities (N=15; 30.4±9.6 yr) while undertaking each of seven ADL: sitting quietly (SitQ); sitting watching television (SitTV); sitting and standing while completing an assembly task (SitAT, StaAT); and walking at a slow (WalkS, 3.0 km h(-1)), quick (WalkQ, 6.0 km h(-1)) and fast (WalkF, 9.0 km h(-1)) speed, under laboratory conditions. Adults with intellectual disabilities were found to expend significantly more energy than adults without intellectual disabilities for SitQ, WalkS, WalkQ and WalkF (p<0.05). Energy expended by both populations was significantly more than CPA values for SitQ, SitTV, SitAT, WalkS, and WalkQ (p<0.02) and significantly less for WalkF (p<0.01). Walking at the speed of 3.0 km h(-1) (50 m min(-1)) was found to be sufficient to achieve moderate-intensity energy expenditure, surpassing the intensity threshold for conferring a health benefit. Energy expenditure inaccuracies of the CPA have important consequences when estimating prevalence of engagement in health enhancing physical activities among population sub-groups. The identification of slow walking as a moderate-intensity physical activity offers significant health promotion opportunities for adults with intellectual disabilities through active transport and leisure.

Body mass index as an indicator of adiposity among adults with intellectual disability.

BACKGROUND: Body mass index (BMI) has been identified as a key health indicator and determinant of health for people with intellectual disability. Our aim was to examine whether BMI is a useful indicator of adiposity among a sample of adults with intellectual disability. METHOD: Participants were 46 ambulatory community-dwelling volunteers with mild to moderate intellectual disability. Age ranged from 19 to 60 years, 25 were male, and 17 had Down syndrome. Soft tissue composition was determined using a dual-energy X-ray absorptiometer (DXA) and height and weight were directly assessed. RESULTS: Regression equations revealed that BMI accounted for 68% of the variance in percent body fat and 83% of the variance in total body fat. Partial correlations of BMI with fat and lean masses determined by DXA were r = .91 and r = -.12, respectively. A BMI of >or= 30 had excellent specificity for obesity, but less than optimal sensitivity. CONCLUSIONS: BMI appears to be a reasonable indicator of adiposity, although a BMI >or= 30 may misclassify a proportion of individuals assessed by DXA as obese.

Cognitive behavioral therapy improves diet and body composition in overweight and obese adolescents.

BACKGROUND: Cognitive behavioral therapy (CBT) teaches behavioral and cognitive strategies that focus on achieving and maintaining lifestyle changes. OBJECTIVE: We examined the effectiveness of a CBT program (CHOOSE HEALTH) for improving body composition, diet, and physical activity in overweight and obese adolescents. DESIGN: Adolescents [16 male, 31 female; aged 14.5 +/- 1.6 y; body mass index (BMI; in kg/m(2)) 30.9 +/- 4.2] were block-matched into 2 groups by age, sex, Tanner stage, BMI, and hip and waist circumferences and were randomly assigned to CBT or no treatment (control). CBT consisted of 10 weekly sessions, followed by 5 fortnightly telephone sessions. RESULTS: Compared with the control, over 20 wk, CBT improved (significant group x time interactions) BMI (CBT, -1.3 +/- 0.4; control, 0.3 +/- 0.3; P = 0.007), weight (CBT, -1.9 +/- 1.0 kg; control, 3.8 +/- 0.9 kg; P = 0.001), body fat (CBT, -1.5 +/- 0.9 kg; control, 2.3 +/- 1.0 kg; P = 0.001), and abdominal fat (CBT, -124.0 +/- 46.9 g; control, 50.1 +/- 53.5 g; P = 0.008). CBT showed a greater reduction in intake of sugared soft drinks as a percentage of total energy (CBT, -4.0 +/- 0.9%; control, -0.3 +/- 0.9%; P = 0.005 for group x time interaction), which was related to reductions in weight (r = 0.48, P = 0.04), BMI (r = 0.53, P = 0.02), and waist circumference (r = 0.54, P = 0.02). Physical activity did not change significantly. CONCLUSIONS: A 10-wk CBT program followed by 10 wk of fortnightly phone contact improved body composition in overweight and obese adolescents. Changes in soft drink consumption may have contributed to this benefit.

Motivational interviewing and cognitive behaviour therapy in the treatment of adolescent overweight and obesity: study design and methodology.

BACKGROUND: Despite the high prevalence and negative physical and psychosocial consequences of overweight and obesity in adolescents, very little research has evaluated treatment in this population. Consequently, clinicians working with overweight and obese adolescents have little empirical research on which to base their practise. Cognitive behavioural therapy has demonstrated efficacy in promoting behaviour change in many treatment resistant disorders. Motivational interviewing has been used to increase motivation for change and improve treatment outcomes. In this paper we describe the rationale and design of a randomised controlled trial testing the efficacy of motivational interviewing and cognitive behaviour therapy in the treatment of overweight and obese adolescents. METHODS: Participants took part in a motivational interview or a standard semi-structured assessment interview and were then randomly allocated to a cognitive behavioural intervention or a wait-list control condition. The cognitive behavioural intervention, the CHOOSE HEALTH Program, consisted of 13 individual treatment sessions (12 face-to-face, 1 phone call) followed by 9 maintenance sessions (7 phone calls, 2 face-to-face). Assessments were conducted prior to participation, after the treatment phase and after the maintenance phase of intervention. Improvement in body composition was the primary outcome; secondary outcomes included improved cardiovascular fitness, eating and physical activity habits, family and psychosocial functioning. CONCLUSION: Despite the demonstrated effectiveness of motivational interviewing and cognitive behavioural therapy in the long-term management of many treatment resistant disorders, these approaches have been under-utilised in adolescent overweight and obesity treatment. This study provides baseline data and a thorough review of the study design and treatment approach to allow for the assessment of the efficacy of motivational interviewing and cognitive behavioural therapy in the treatment of adolescent overweight and obesity. Data obtained in this study will also provide much needed information about the behavioural and psychosocial factors associated with adolescent overweight and obesity.

Perspectives of constraining and enabling factors for health-promoting physical activity by adults with intellectual disability.

BACKGROUND: Physical activity influences health in individuals and within populations. This study explored factors perceived as enabling or inhibiting participation in physical activity by adults with intellectual disability from a health promotion perspective. METHOD: Six focus group interviews were conducted: adults with intellectual disability (1 group, n = 9), direct care workers (1 group, n = 5), group home supervisors (2 groups, n = 9 and n = 6), managers (1 group, n = 4), and parents (1 group, n = 7). RESULTS: Three major themes were identified from the focus group interviews: motivation for participation, social support, and political and financial support. CONCLUSIONS: The most critical issue was the lack of clear policies. Both day training centres and accommodation services would benefit from development of policies related to health-promoting physical activity. Flowing on logically from the development of policy would be much needed training and support of staff.