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.

Environmental and cultural change on the Mt Eccles lava-flow landscapes of southwest Victoria, Australia

The Gunditjmara people developed a socio-economic system based on the modification of wetland ecosystems associated with the Mt Eccles lava flow primarily for sustainable production and management of the highly nutritious shortfin eel (Anguilla australis). This paper examines the environmental history of these landscapes since their inception about 30 000 years ago, through palaeoecological analysis of sediment cores from associated lakes and swamps, in order to contribute to an understanding of the causes and timing of cultural transformation. Two records cover the whole of the 30 000 year history of the landscape while two others provide evidence of change within the Holocene. A great deal of variation within the landscape is revealed, both temporally and spatially, with opportunities for human exploitation through the whole recorded period. Although most features of the records can be explained by natural landscape development and climate change, some human modification can be suggested from around the Pleistocene—Holocene transition while more obvious indications of management relating to eel aquaculture are evident from about 4000 cal. yr BP that appear to include adaptations to the onset of a drier and more variable climate. The study has implications for the explanation of intensification of settlement in Australia more generally within the mid to late Holocene.

Process evaluation of an integrated health promotion/occupational health model in WellWorks-2

Disparities in chronic disease risk by occupation call for newapproaches to health promotion. Well Works-2 was a randomized, controlled study comparing the effectiveness of a health promotion/occupational health program (HP/OHS) with a standard intervention (HP). Interventions in both studies were based on the same theoretical foundations. Results from process evaluation revealed that a similar number of activities were offered in both conditions and that in the HP/OHS condition there were higher levels of worker participation using three measures: mean participation per activity (HP: 14.2% vs. HP/OHS: 21.2%), mean minutes of worker exposure to the intervention/site (HP: 14.9 vs. HP/OHS: 33.3), and overall mean participation per site (HP: 34.4% vs. HP/ OHS: 45.8%). There were a greater number of contacts with management (HP: 8.8 vs. HP/OHS: 24.9) in the HP/ OHS condition. Addressing occupational health may have contributed to higher levels of worker and management participation and smoking cessation among blue-collar workers.

Cost effectiveness of surveillance for isocyanate asthma : finding an occupational health policy framework

Wild et al present an original cost effectiveness analysis for medical surveillance for isocyanate asthma in this issue of OEM.1 The general case for surveillance for isocyanate asthma is a compelling one. Most occupational physicians, practitioners, and researchers might rightly expect that if a cost effectiveness (CE) case cannot be made for this agent, it would be hard to make a case for most others. The causal link between isocyanate exposure and asthma is well established, and more is known about the pathophysiology, natural history, long term consequences, and benefits of medical surveillance in this instance than for most other occupational exposures.A mathematical simulation model was developed based on a carefully specified set of clinical parameters, drawing from empirical studies where possible (for example, in estimating sensitisation rates ranging from 0.7% to 5.3% per year), and well qualified expert opinion otherwise (for example, in estimating the chance of removal from exposure if a patient is diagnosed versus undiagnosed). Their “state transition” model compared passive case finding to surveillance (the heart of the CE analysis question as proposed) for a theoretical population of 100 000 otherwise healthy and exposed workers, predicting their progression over 10 years across three mutually exclusive “states”: healthy and exposed; symptomatic; and disabled. This alone is an impressive and valuable piece of research, integrating a substantial body of empirical research to show that surveillance is estimated to result in 700 fewer cases of disability over 10 years compared to passive case finding. While such a modelling exercise necessarily requires numerous assumptions and simplifications, each was well articulated and defensible.