Standardizing anthropometric measures in children and adolescents with new functions for egen

A new function for egen has been developed to allow transformation of child anthropometric data to z-scores using the LMS method and the reference data available from the 1990 British Growth Reference and the 2000 US CDC Growth Reference. An additional function allows for children to be categorized according to body mass index (weight/height ²) using international cutoff points recommended by the Childhood Obesity Working Group of the International Obesity Taskforce. Copyright 2004 by StataCorp LP.

Over and undernutrition in the children of Australian immigrants : assessing the influence of birthplace of primary carer and english language use at home on the nutritional status of 4-5-year-olds

Objective. To document the relationship between childhood nutrition status and ethnicity (defined as the birthplace of primary carer and English language use at home) using a nationally representative sample of 4- to 5-year-old children. Design and participants. Cross-sectional population survey of 4 983 4- to 5-year-old children (2 537 boys and 2 446 girls) as part of Wave 1 (2004) of the Longitudinal Study of Australian Children. Main outcome measures. Overweight/obesity and thinness using the newly published body mass index cut-off points of Cole (2007). Results. In total, 20.6% (95%CI 19.5, 21.7) of children aged 4 to 5 years were estimated to be overweight or obese, while 1.0% (95%CI 0.8, 1.3) was thin. Unadjusted analyses showed a significant relationship between childhood overweight/obesity and primary carer's country of birth (χ2=15.9, p<0.01), but the significance became minimal after adjusting for socio-economic and demographic factors. The adjusted model suggests that boys of primary carer's born in Europe (excluding UK and Ireland) were less likely to be overweight/obese than boys whose primary carers were born in Australia, but the overall effect size was negligible. No difference was found for girls. In addition, boys who mainly spoke English at home were less likely to be overweight/obese (OR=0.49; 95%CI 0.27, 0.88; p=0.017) and thin (OR=0.27; 95%CI 0.12, 0.62; p=0.002) than boys who spoke a language other than English at home. No difference was found for girls. Conclusions. There is a relationship between main language spoken at home and nutritional status in 4-5-year-old boys but not girls. The use of English language at home may be a protective factor for normal weight in young boys. After adjustment for socio-economic and demographics characteristics, there was a negligible relationship between overweight/obesity in children and their primary carer's country of birth.

Double disadvantage : the influence of ethnicity over socioeconomic position on childhood overweight and obesity: findings from an inner urban population of primary school children

Objective: To examine the relationship between overweight/obesity in children, socioeconomic status and ethnicity/cultural background.

Design: Cross-sectional survey of children aged 4–13 years.

Setting: A total of 23 primary (elementary) schools in an inner urban municipality of Melbourne, Australia.

Participants: A total of 2685 children aged 4–13 years and their parents.

Main exposure measures: Ethnicity/cultural background – maternal region of birth; socioeconomic position (SEP) indicators – maternal and paternal educational attainment, family employment status, possession of a healthcare card, ability to buy food, indicator of disadvantage (Socioeconomic Index for Areas, SEIFA) score for school; parental weight status.

Main outcome measure: Prevalence of overweight/obesity.

Results: Prevalence of overweight/obesity approached 1 in 3 (31%) in this sample. Prevalence of overweight/obesity was greater for children of both North Africa and Middle Eastern background and children of Southern, South Eastern and Eastern European background compared with children of Australian background. This difference remained after adjusting for age, sex, height, clustering by school, SEP indicators and parental weight status; odds ratio, OR=1.57 (95% confidence interval, CI 1.12–2.19) and 1.88 (95%CI 1.24–2.85), respectively.

Conclusions: There is a clear independent effect of ethnicity above and beyond the effect of socioeconomic status on overweight and obesity in children. Further research is required to explore the mediators of this gradient.

Is dog ownership or dog walking associated with weight status in children and their parents?

Issue addressed: Several studies have shown that dog owners do more physical activity than non-owners; however, associations with weight status are unknown. This study examined associations between dog ownership, frequency of dog walking and weight status among children and their parents. Methods: Height and weight were measured for 281 children aged 5-6 years and 864 children aged 10-12 years. One parent reported their own and their partner's height and weight (n=1,108), dog ownership, usual frequency their child walks a dog, and usual frequency of walking the dog as a family. Logistic regression analyses were adjusted for sex (children only), physical activity, education, neighbourhood SES, parental weight status (children only) and clustering by school. Results: Dog ownership ranged from 45-57% in the two age groups. Nearly one in four 5-6 year-olds and 37% of 10-12 year- olds walked a dog at least once/week. Weekly dog walking as a family was reported by 24-28% of respondents. The odds of being overweight or obese were lower among younger children who owned a dog (OR=0.5, 95% CI 0.3-0.8) and higher among mothers whose family walked the dog together (OR--1.3, 95% CI 1.0-1.7). Conclusions: Dog ownership may offer some protection from overweight among young children. It is important that families with a dog are encouraged to walk or play with it regularly. Associations with weight status may depend on the type of dog owned, length of ownership and the nature of walks or interaction.

Family food environments as determinants of children's eating : implications for obesity prevention

The prevalence of childhood obesity is escalating rapidly and it considered to be a major public health problem. Diet is a recognised precursor of fatness, and current evidence supports the premise that in Westernised countries, the dietary intakes of children are likely to be important in obesity genesis. However, we have a relatively poor understanding of the environments in which a child’s eating is learnt and maintained. Much of the existing work in this area is based on small-scale or experimental studies, or has been derived from homogeneous populations within the USA. Despite these limitations, there is evidence that aspects of the child’s family environment are likely to be important in determining obesity risk in children. This thesis examines the impact of the family food environment on a child’s eating through two related studies. The first study, titled the Children and Family Eating (CAFÉ) study comprised three phases. Phase one involved qualitative interviews with 17 parents of 5-6 year-old children to explore parental perceptions regarding those factors in a child’s environment believed to influence the development of their child’s eating habits. These interviews were used to inform the development of quantitative measures of the family food environment. The second phase involved the development of a Food Frequency Questionnaire (FFQ) to assess dietary intake in 5-6 year-olds. The FFQ was informed by analysis of 1995 Australian National Nutrition Survey data. In the final phase the relationships between dietary intakes of 5-6 year-old children, and potential predictors of dietary intake were examined in a cross-sectional study of 560 families. Predictors included measures of: parental perceptions of the adequacy of their child’s diet; food availability and accessibility; child-feeding; the opportunities for parental modelling of food intake; a child’s television exposure; maternal Body Mass Index; and maternal education. Analysis of the CAFÉ data provides unique information regarding the relationships between a child’s family food environment and their food consumption. Models developed for a range of dietary outcomes considered to be predictive of increased risk for obesity, including total energy and fat intakes, vegetable variety, vegetable consumption, and high-energy (non-dairy) fluid consumption, explained between 11 and 20 percent of the variance in dietary intake. Two aspects of the family food environment, parental perception of a child’s dietary adequacy, and the total minutes of television viewed per day, were frequently found to be predictive of dietary outcomes likely to promote fatness in these children. The second study, titled the Parent Education and Support (PEAS) Feeding Intervention Study, was a prospective pre/post non-randomised intervention trial that assessed the impact of a feeding intervention to 240 first-time mothers of one-year-old children. This intervention focused on one aspect of the family food environment, child-feeding, which has been proposed as influential in the development of obesogenic eating behaviours. In this study, Maternal and Child Health Nurses (MCHNs), using a ‘Division of Responsibility’ model of feeding, taught parents to provide nutritious food at regular intervals and to let children decide if to eat and how much to eat. Thus parents were encourages to food their child without exerting pressure, or employing coercion or rewards (controlling behaviours). The aim was to influence parental attitudes and beliefs regarding child-feeding. Through the use of these feeding techniques, this intervention also aimed to increase the variety of fruits and vegetables a child consumed by teaching parents to persist with offering these foods, over the year of the intervention, in non-emotive environments. Fruits and vegetables were chosen in this intervention because they are likely to be protective in the development of obesity. Analysis of the PEAS data suggests that this low-level feeding intervention, delivered through existing Maternal and Child Health services, was modestly effective in changing parental attitudes and beliefs regarding the feeding of young children. Further, the validity of fruits offered to intervention group children increased. This thesis expands the existing knowledge base by providing a comprehensive analysis of the relative impact of aspects of the family environment on dietary intakes of 5-6 year-olds. Further, the analysis of a feeding intervention in first-time parents provides important insights regarding the potential to influence child-feeding and the impact this may have on the promotion of eating behaviours protective against obesity.

Reducing obesity in early childhood : results from romp & chomp, an Australian community-wide intervention program

Background: There is growing evidence that community-based interventions can reduce childhood obesity in older children.
Objective: We aimed to determine the effectiveness of the Romp & Chomp intervention in reducing obesity and promoting healthy eating and active play in children aged 0–5 y.
Design: Romp & Chomp was a community-wide, multisetting, multistrategy intervention conducted in Australia from 2004 to 2008. The intervention occurred in a large regional city (Geelong) with a target group of 12,000 children and focused on community capacity building and environmental (political, sociocultural, and physical) changes to increase healthy eating and active play in early-childhood care and educational settings. The evaluation was repeat cross-sectional with a quasiexperimental design and comparison sample. Main outcome measures were body mass index (BMI), standardized BMI (zBMI; according to the Centers for Disease Control and Prevention 2000 reference charts), and prevalence of overweight/obesity and obesity-related behaviors in children aged 2 and 3.5 y.
Results: After the intervention there was a significantly lower mean weight, BMI, and zBMI in the 3.5-y-old subsample and a significantly lower prevalence of overweight/obesity in both the 2- and 3.5-y-old subsamples (by 2.5 and 3.4 percentage points, respectively) than in the comparison sample (a difference of 0.7 percentage points; P < 0.05) compared with baseline values. Intervention child-behavioral data showed a significantly lower intake of packaged snacks (by 0.23 serving), fruit juice (0.52 serving), and cordial (0.43 serving) than that in the comparison sample (all P < 0.05).
Conclusion: A community-wide multisetting, multistrategy intervention in early-childhood settings can reduce childhood obesity and improve young children's diets. This trial was registered with the Australian Clinical Trials Registry at anzctr.org.au as ACTRN12607000374460.

Relationships between measures of fitness, physical activity, body composition and vascular function in children

Background : The prevalence of obesity and physical inactivity in Western countries has increased rapidly. Both are modifiable risk factors for cardiovascular disease. Atherosclerosis begins in childhood and endothelial dysfunction is its earliest detectable manifestation.

Methods : We assessed flow-mediated dilation (FMD) in 129 children (75 female; 10.3 + 0.3 yrs; 54 male; 10.4; 0.3 yrs). FMD was normalised for differences in the eliciting shear rate stimulus between subjects (SR_AUC). Fitness was assessed as peak oxygen uptake during an incremental treadmill exercise test (VO₂peak). Body composition was measured using a dual-energy X-ray absorptiometry (DEXA) scan. Physical activity (PA) was assessed using Actigraph accelerometers. The cohort was split into tertiles according to FMD% and also FMD% corrected for SR_AUC to gain insight into the determinants of vascular function.

Results : Across the cohort, significant correlations were observed between FMD%/SR_AUC and DEXA percentage fat (r = &minus;0.23, p = 0.009) and percentage lean mass (r = 0.21, p = 0.008), and also with PA performed at moderate-to-high intensity (r = 0.363, p = 0.001). For children in the lowest FMD%/SR_AUC tertile, a stronger relationship with all PA measures was observed, particularly with high intensity PA (r = 0.572, P = 0.003). Regression analysis revealed that high intensity PA was the only predictor of impaired FMD%/SR_AUC.

Conclusions : These data suggest that traditional risk factors for CHD in adult populations impact upon vascular function in young people. Furthermore, it appears that individuals with impaired FMD may benefit from performing high intensity PA, whereas no relationships exist between FMD and lower intensities of PA or between PA and FMD in those subjects who possess preserved vascular function a priori.

Neighbourhood physical activity environments and adiposity in children and mothers : a three-year longitudinal study

Background Although neighbourhood environments are often blamed for contributing to rising levels of obesity, current evidence is based predominantly on cross-sectional samples. This study examined associations between objectively-measured environmental characteristics of neighbourhoods and adiposity cross-sectionally and longitudinally over three years in children and their female carers.

Methods Longitudinal study of 140 5-6 year-old and 269 10-12 year-old children and their female carers (n = 369). At baseline (2001) and follow-up (2004), height and weight were measured among children and self-reported among female carers, and were used to compute BMI z-scores and BMI, respectively. A Geographic Information System determined access to destinations (public open spaces, sports options, walking/cycling tracks), road connectivity (density of cul-de-sacs and intersections, proportion of 4-way intersections, length of 'access' paths (overpasses, access lanes, throughways between buildings)) and traffic exposure (length of 'busy' and 'local' roads) within 800 m and 2 km of home. Univariate and multivariable linear regression analyses examined associations between environmental characteristics and BMI/BMI z-scores at baseline and change in BMI/BMI z-scores over the three years.

Results Cross-sectionally, BMI z-score was inversely associated with length (km) of access paths within 800 m (b = -0.50) and 2 km (b = -0.16) among younger and number of sport/recreation public open spaces (b = -0.14) and length (km) of 'access' paths (b = -0.94) within 800 m and length of local roads within 2 km (b = -0.01) among older children. Among female carers, BMI was associated with length (km) of walking/cycling tracks (b = 0.17) and busy roads (b = -0.34) within 800 m. Longitudinally, the proportion of intersections that were 4-way (b = -0.01) within 800 m of home was negatively associated with change in BMI z-score among younger children, while length (km) of access paths (b = 0.18) within 800 m was significant among older children. Among female carers, options for aerobics/fitness and swimming within 2 km were associated with change in BMI (B = -0.42).

Conclusion A small number of neighbourhood environment features were associated with adiposity outcomes. These differed by age group and neighbourhood scale (800 m and 2 km) and were inconsistent between cross-sectional and longitudinal findings. However, the results suggest that improvements to road connectivity and slowing traffic and provision of facilities for leisure activities popular among women may support obesity prevention efforts.

Interventions to prevent obesity in 0-5 year olds : an updated systematic review of the literature

The small number and recency of the early childhood obesity-prevention literature identified in a previous review of interventions to prevent obesity, promote healthy eating, physical activity, and/or reduce sedentary behaviors in 0-5 year olds suggests this is a new and developing research area. The current review was conducted to provide an update of the rapidly emerging evidence in this area and to assess the quality of studies reported. Ten electronic databases were searched to identify literature published from January 1995 to August 2008. Inclusion criteria: interventions reporting child anthropometric, diet, physical activity, or sedentary behavior outcomes and focusing on children aged 0-5 years of age. Exclusion criteria: focusing on breastfeeding, eating disorders, obesity treatment, malnutrition, or school-based interventions. Two reviewers independently extracted data and assessed study quality. Twenty-three studies met all criteria. Most were conducted in preschool/childcare (n = 9) or home settings (n = 8). Approximately half targeted socioeconomically disadvantaged children (n = 12) and three quarters were published from 2003 onward (n = 17). The interventions varied widely although most were multifaceted in their approach. While study design and quality varied most studies reported their interventions were feasible and acceptable, although impact on behaviors that contribute to obesity were not achieved by all. Early childhood obesity-prevention interventions represent a rapidly growing research area. Current evidence suggests that behaviors that contribute to obesity can be positively impacted in a range of settings and provides important insights into the most effective strategies for promoting healthy weight from early childhood.