Multilevel analysis of the Be Active Eat Well intervention: environmental and behavioural influences on reductions in child obesity risk.

BACKGROUND: The Be Active Eat Well (BAEW) community-based child obesity prevention intervention was successful in modestly reducing unhealthy weight gain in primary school children using a multi-strategy and multi-setting approach. OBJECTIVE: To (1) examine the relationship between changes in obesity-related individual, household and school factors and changes in standardised child body mass index (zBMI), and (2) determine if the BAEW intervention moderated these effects. METHODS: The longitudinal relationships between changes in individual, household and school variables and changes in zBMI were explored using multilevel modelling, with measurement time (baseline and follow-up) at level 1, individual (behaviours, n = 1812) at level 2 and households (n = 1318) and schools (n = 18) as higher levels (environments). The effect of the intervention was tested while controlling for child age, gender and maternal education level. RESULTS: This study confirmed that the BAEW intervention lowered child zBMI compared with the comparison group (-0.085 units, P = 0.03). The variation between household environments was found to be a large contributor to the percentage of unexplained change in child zBMI (59%), compared with contributions from the individual (23%) and school levels (1%). Across both groups, screen time (P = 0.03), sweet drink consumption (P = 0.03) and lack of household rules for television (TV) viewing (P = 0.05) were associated with increased zBMI, whereas there was a non-significant association with the frequency the TV was on during evening meals (P = 0.07). The moderating effect of the intervention was only evident for the relationship between the frequency of TV on during meals and zBMI, however, this effect was modest (P = 0.04). CONCLUSIONS: The development of childhood obesity involves multi-factorial and multi-level influences, some of which are amenable to change. Obesity prevention strategies should not only target individual behaviours but also the household environment and family practices. Although zBMI changes were modest, these findings are encouraging as small reductions can have population level impacts on childhood obesity levels.

Reducing unhealthy weight gain in children through community capacity-building: results of a quasi-experimental intervention program, Be Active Eat Well.

BACKGROUND: Be Active Eat Well (BAEW) was a multifaceted community capacity-building program promoting healthy eating and physical activity for children (aged 4-12 years) in the Australian town of Colac. OBJECTIVE: To evaluate the effects of BAEW on reducing children's unhealthy weight gain. METHODS: BAEW had a quasi-experimental, longitudinal design with anthropometric and demographic data collected on Colac children in four preschools and six primary schools at baseline (2003, n=1001, response rate: 58%) and follow-up (2006, n=839, follow-up rate: 84%). The comparison sample was a stratified random selection of preschools (n=4) and primary schools (n=12) from the rest of the Barwon South Western region of Victoria, with baseline assessment in 2003-2004 (n=1183, response rate: 44%) and follow-up in 2006 (n=979, follow-up rate: 83%). RESULTS: Colac children had significantly lower increases in body weight (mean: -0.92 kg, 95% CI: -1.74 to -0.11), waist (-3.14 cm, -5.07 to -1.22), waist/height (-0.02, -0.03 to -0.004), and body mass index z-score (-0.11, -0.21 to -0.01) than comparison children, adjusted for baseline variable, age, height, gender, duration between measurements and clustering by school. In Colac, the anthropometric changes were not related to four indicators of socioeconomic status (SES), whereas in the comparison group 19/20 such analyses showed significantly greater gains in anthropometry in children from lower SES families. Changes in underweight and attempted weight loss were no different between the groups. CONCLUSIONS: Building community capacity to promote healthy eating and physical activity appears to be a safe and effective way to reduce unhealthy weight gain in children without increasing health inequalities.

Lunchbox contents of Australian school children: room for improvement.

OBJECTIVE: In light of the increasing prevalence of obesity in children and the potential of schools as a setting for intervention, we aimed to identify the main foods and beverages consumed at primary school and to determine differences in consumption patterns between children who used the school canteen and those who did not. DESIGN: Cross-sectional survey of school foods in 1681 5-12 y old children, 2003-2004. SETTING: Barwon South-Western region of Victoria, Australia. RESULTS: The school food provided an average (+/-s.e.m.) of 3087+/-26 kJ. Bread was the most frequently consumed food and contributed 20% of total energy at school, biscuits 13%, fruit 10%, muesli/fruit bars 8%, packaged snacks 7%, and fruit juice/cordial 6%. About 10% of children used the school canteen and these children obtained more total energy and more energy from cakes, fast foods and soft drink than noncanteen users (P<0.001). In all, 68% of children had fruit in their lunchboxes, however, over 90% of children had energy-dense, micronutrient-poor snacks ('junk food'). CONCLUSIONS: Fruit intake in primary schools seems reasonably high but could be targeted for further increase as part of promoting a healthy diet. Of concern, however, are the excessive amounts of energy-dense foods in school lunchboxes. These should be considered a priority for health promotion efforts along with reducing the consumption of sweetened drinks. These measures are urgently needed to improve the school-based diets of Australian children and attempt to curb the increasing prevalence of childhood obesity.

Overweight and obesity prevalence in children based on 6- or 12-month IOTF cut-points: does interval size matter?

The International Obesity Taskforce (IOTF) recommends using age- and gender-specific body mass index (BMI) cut-points for defining the prevalence of overweight and obesity in children. These are given in both 6- and 12-month age intervals. Since the BMI-for-age curves are nonlinear, a degree of bias will be introduced when age intervals are wide. We aimed to quantify this bias in prevalence estimates in 2178 Australian children aged 4-12 years using 12- versus 6-month age intervals. Using the 12-month interval, the prevalence of overweight and obesity was underestimated by 1.4% compared to the 6-month interval estimates; however, this was age-dependent. It overestimated prevalence for 4-year olds, but underestimated it for older ages by up to 2.6%. Overweight prevalence was generally affected more than obesity prevalence. The use of different age intervals for IOTF cut-points introduces a small but systematic bias in prevalence estimates of overweight and obesity.

The Taq IA and Ser311 Cys polymorphisms in the dopamine D2 receptor gene and obesity.

Dopamine D2 receptors (DRD2) in the central nervous system are involved in the regulation of feeding. It remains to be elucidated if mutations in the DRD2 gene contribute to the development of obesity. The aim of the present study was to investigate whether the Taq IA and Ser311Cys polymorphisms in the DRD2 gene are associated with obesity in Nauruan and Australian subjects. Subjects were selected based on extremes of the body mass index (BMI) distribution. Two groups of Australian women were selected. The leanest group had a mean BMI of 22.5 kg/m2 (range: 20.3-24.3) and the heaviest group had a mean of 36.1 kg/m2 (32.5-44.1). Four groups of Nauruan subjects were selected. Leanest men had a mean BMI of 33.0 kg/m2 (28.4-36.9), heaviest men had a mean of 52.8 kg/m2 (46.5-69.2), leanest women had a mean of 34.8 kg/m2 (28.2-41.8) and heaviest women had a mean of 55.1 kg/m2 (49.3-73.8). Subjects were genotyped for the Taq IA and Ser311Cys polymorphisms using polymerase chain reaction (PCR) restriction fragment length polymorphism analysis and allelic discrimination Taqman PCR respectively. Leanest and heaviest groups were examined for differences in genotype frequency. Taq IA and Ser311Cys genotype frequencies did not differ significantly between leanest and heaviest Nauruan groups, or between leanest and heaviest Australians. Haplotype frequencies of these polymorphisms did not differ between leanest and heaviest groups. The Taq IA and Ser311Cys polymorphisms in the DRD2 gene are unlikely to be common causes of obesity in these populations.