Ralph Chapman

Effects of improved home heating on asthma in community dwelling children: randomised controlled trial

Objective To assess whether non-polluting, more effective home heating (heat pump, wood pellet burner, flued gas) has a positive effect on the health of children with asthma. Design Randomised controlled trial. Setting Households in five communities in New Zealand. Participants 409 children aged 6-12 years with doctor diagnosed asthma. Interventions Installation of a non-polluting, more effective home heater before winter. The control group received a replacement heater at the end of the trial. Main outcome measures The primary outcome was change in lung function (peak expiratory flow rate and forced expiratory volume in one second, FEV1). Secondary outcomes were child reported respiratory tract symptoms and daily use of preventer and reliever drugs. At the end of winter 2005 (baseline) and winter 2006 (follow-up) parents reported their child’s general health, use of health services, overall respiratory health, and housing conditions. Nitrogen dioxide levels were measured monthly for four months and temperatures in the living room and child’s bedroom were recorded hourly. Results Improvements in lung function were not significant (difference in mean FEV1 130.7 ml, 95% confidence interval −20.3 to 281.7). Compared with children in the control group, however, children in the intervention group had 1.80 fewer days off school (95% confidence interval 0.11 to 3.13), 0.40 fewer visits to a doctor for asthma (0.11 to 0.62), and 0.25 fewer visits to a pharmacist for asthma (0.09 to 0.32). Children in the intervention group also had fewer reports of poor health (adjusted odds ratio 0.48, 95% confidence interval 0.31 to 0.74), less sleep disturbed by wheezing (0.55, 0.35 to 0.85), less dry cough at night (0.52, 0.32 to 0.83), and reduced scores for lower respiratory tract symptoms (0.77, 0.73 to 0.81) than children in the control group. The intervention was associated with a mean temperature rise in the living room of 1.10°C (95% confidence interval 0.54°C to 1.64°C) and in the child’s bedroom of 0.57°C (0.05°C to 1.08°C). Lower levels of nitrogen dioxide were measured in the living rooms of the intervention households than in those of the control households (geometric mean 8.5 μg/m3 v 15.7 μg/m3, P<0.001). A similar effect was found in the children’s bedrooms (7.3 μg/m3 v 10.9 μg/m3, P<0.001). Conclusion Installing non-polluting, more effective heating in the homes of children with asthma did not significantly improve lung function but did significantly reduce symptoms of asthma, days off school, healthcare utilisation, and visits to a pharmacist. Trial registration Clinical Trials NCT00489762.

Retrofitting houses with insulation: a cost–benefit analysis of a randomised community trial

Background: Housing is an important environmental influence on population health, and there is growing evidence of health effects from indoor environment characteristics such as low indoor temperatures. However, there is relatively little research, and thus little firm guidance, on the cost-effectiveness of public policies to retrospectively improve the standards of houses. The purpose of this study was to value the health, energy and environmental benefits of retrofitting insulation, through assessing a number of forms of possible benefit: a reduced number of visits to GPs, hospitalisations, days off school, days off work, energy savings and CO2 savings. Methods: All these metrics are used in a cluster randomised trial—the “Housing, Insulation and Health Study”—of retrofitting insulation in 1350 houses, in which at least one person had symptoms of respiratory disease, in predominantly low-income communities in New Zealand. Results: Valuing the health gains, and energy and CO2 emissions savings, suggests that total benefits in “present value” (discounted) terms are one and a half to two times the magnitude of the cost of retrofitting insulation. Conclusion: This study points to the need to consider as wide a range of benefits as possible, including health and environmental benefits, when assessing the value for money of an intervention to improve housing quality. From an environmental, energy and health perspective, the value for money of improving housing quality by retrofitting insulation is compelling.

Increasing active travel: results of a quasi-experimental study of an intervention to encourage walking and cycling

Background There is increased interest in the effectiveness and cobenefits of measures to promote walking and cycling, including health gains from increased physical activity and reductions in fossil fuel use and vehicle emissions. This paper analyses the changes in walking and cycling in two New Zealand cities that accompanied public investment in infrastructure married with programmes to encourage active travel. Method Using a quasi-experimental two-group pre–post study design, we estimated changes in travel behaviour from baseline in 2011 to mid-programme in 2012, and postprogramme in 2013. The intervention and control cities were matched in terms of sociodemographic variables and baseline levels of walking and cycling. A face-to-face survey obtained information on walking and cycling. We also drew from the New Zealand Travel Survey, a national ongoing survey of travel behaviour, which was conducted in the study areas. Estimates from the two surveys were combined using meta-analysis techniques. Results The trips and physical activity were evaluated. Relative to the control cities, the odds of trips being by active modes (walking or cycling) increased by 37% (95% CI 8% to 73%) in the intervention cities between baseline and postintervention. The net proportion of trips made by active modes increased by about 30%. In terms of physical activity levels, there was little evidence of an overall change. Discussion Comparing the intervention cities with the matched controls, we found substantial changes in walking and cycling, and conclude that the improvements in infrastructure and associated programmes appear to have successfully arrested the general decline in active mode use evident in recent years.

Dealing with changing risks: a New Zealand perspective on climate change adaptation

Future changes in New Zealand’s climate are expected to be less than in many other countries, and New Zealand has well-established governance structures for dealing with environmental risks. While this might imply that adaptation would be straightforward, extensive public and private investments, as well as many traditional Māori assets and cultural values, are in areas increasingly at risk of flooding and sea level rise. In order to consider the country’s adaptive capacity in more detail, we have used an empirical research approach, working with government practitioners at three levels and with Māori communities. Very different perceptions of risk, and structural inertia in planning processes have emerged as key issues for implementing adaptation responses. In particular, the use of static frameworks biases responses towards retrospective, rather than anticipatory analysis. Ongoing socioeconomic changes in New Zealand also raise the risk of structural effects caused by climate change impacts becoming unevenly distributed across society. Our analysis indicates that a national and regional strategic approach, centred on a dynamic view of climate risk, is necessary for effective decisions at the local government and community level. In addition, effective adaptation requires better identification of barriers and opportunities for addressing changing risk, together with more effective and continuous social engagement.

Improving health and energy efficiency through community-based housing interventions

ObjectivesHouses designed for one climate and cultural group may not be appropriate for other places and people. Our aim is to find cost-effective ways to improve the characteristics of older homes, ill-fitted for New Zealand’s climate, in order to improve the occupants’ health.MethodWe have carried out two community randomised trials, in partnership with local communities, which have focused on retrofitted insulation and more effective heating and have two other studies under way, one which focuses on electricity vouchers and the other on housing hazard remediation.ResultsThe Housing, Insulation and Health Study showed that insulating 1,350 houses, built before insulation was required, improved the occupants’ health and well being as well as household energy efficiency. In the Housing, Heating and Health Study we investigated the impact of installing more effective heating in insulated houses for 409 households, where there was a child with doctor-diagnosed asthma. Again, the study showed significant results in the intervention group; indoor temperatures increased and levels of NO2 were halved. Children reported less poor health, lower levels of asthma symptoms and sleep disturbances by wheeze and dry cough. Children also had fewer days off school.ConclusionImproving the energy efficiency of older housing leads to health improvements and energy efficiency improvements. Multidisciplinary studies of housing interventions can create compelling evidence to support policies for sustainable housing developments which improve health.

Transitioning to Low-Carbon Urban Form and Transport in New Zealand

There is a growing sense of urgency internationally about cutting greenhouse gas emissions. If New Zealand is to continue to position itself as a truly sustainable nation, it will need to take radical and effective steps to reduce its transport-related carbon dioxide emissions. Even if New Zealand were not to take early action, it is likely that it would come under strong international pressure to stay in step with progressive countries. The government has recently committed, in principle, to cutting domestic transport related emissions by 50 percent by 2040, but it is not yet clear that the measures the government has proposed will get New Zealand to this target. This paper examines the policy opportunities provided by urban form and transport, arguing that these issues have been little explored to date in New Zealand in terms of their potential to reduce carbon emissions, and provide co-benefits such as health gains and cost savings. Ensuring that urban development and transport policies are highly innovative and integrated will be critical to the sustainability transition that New Zealand is now beginning to make, including the transition to low-carbon transport.

Housing and health: The relationship between research and policy

There is a long tradition of using housing interventions to promote public health, despite causative factors being unclear. This article reviews the research evidence on the key aspects of poor housing such as inadequate maintenance, over crowding, low temperatures and dampness, that have been identified as contributing to the impact of housing on health. Possible intervening factors such as house dust mites and fungi are also reviewed. This evidence is discussed in the context of possible confounding factors such as housing location and tenure. Conclusions are drawn about the adequacy of the research evidence as a basis for changing building regulations and other policy measures as a way of improving health.

Increasing active travel: aims, methods and baseline measures of a quasi-experimental study

BackgroundPolicy advisers are seeking robust evidence on the effectiveness of measures, such as promoting walking and cycling, that potentially offer multiple benefits, including enhanced health through physical activity, alongside reductions in energy use, traffic congestion and carbon emissions. This paper outlines the ‘ACTIVE’ study, designed to test whether the Model Communities Programme in two New Zealand cities is increasing walking and cycling. The intervention consists of the introduction of cycle and walkway infrastructure, along with measures to encourage active travel. This paper focuses on the rationale for our chosen study design and methods.MethodThe study design is multi-level and quasi-experimental, with two intervention and two control cities. Baseline measures were taken in 2011 and follow-up measures in 2012 and 2013. Our face-to-face surveys measured walking and cycling, but also awareness, attitudes and habits. We measured explanatory and confounding factors for mode choice, including socio-demographic and well-being variables. Data collected from the same households on either two or three occasions will be analysed using multi-level models that take account of clustering at the household and individual levels. A cost-benefit analysis will also be undertaken, using our estimates of carbon savings from mode shifts. The matching of the intervention and control cities was quite close in terms of socio-demographic variables, including ethnicity, and baseline levels of walking and cycling.DiscussionThis multidisciplinary study provides a strong design for evaluating an intervention to increase walking and cycling in a developed country with relatively low baseline levels of active travel. Its strengths include the use of data from control cities as well as intervention cities, an extended evaluation period with a reasonable response rate from a random community survey and the availability of instrumental variables for sensitivity analyses.

Towards zero carbon? Constrained policy action in two New Zealand cities

ABSTRACT Transportation was Aotearoa/New Zealand’s fastest-growing sector in terms of carbon emissions over the last two decades. This article investigates mitigation policies for transportation emissions in the two most prosperous cities, Wellington and Auckland. Analysing local government policy documents, we dissect commitments and examine the gap between aspirations and outcomes. Neither city’s emissions are falling significantly despite trends towards housing intensification, which can cut emissions via shorter journeys. The mode share of motor vehicles in total commuting trips is only gradually diminishing, while the share of walking and cycling is only marginally increasing. We explore possible explanations for the slow progress in achieving aspirations. Our main findings are: first, there is a significant ambition gap between councils’ stated goals, on the one hand, and measures adopted by councils, on the other; and second, ‘business as usual’ policies of central government are dampening these cities’ will and ability to adopt more sustainable policies. We conclude that city mitigation performance will likely be modest until the central government’s stance changes, but there is nevertheless a strong case, and clear opportunities, for Auckland and Wellington to strengthen their emission reductions.

Valuing social housing needs to take a broader view

Tenements were viewed as plague houses in nineteenth century industrial cities such as Glasgow, London, New York and Berlin. Replacing the tenements with social housing was seen as a key marker of social progress in the late 19th and 20th centuries. But as austerity budgets have spread across national and local governments in the 21st century, public expenditure on social housing, like other collective services, is not necessarily protected. Yet success in breaking the link between poor housing and health inequalities critically depends on retaining a social role for housing.1 How can public health researchers make the case that good quality housing is an upstream determinant of health? Good quality housing for low-income people is a public good which is under-provided by the private market—the market ignores negative spillovers, such as infectious disease, as well as social spillovers, such as community instability affecting education outcomes. Attaining positive health and social outcomes therefore requires some public funding to be sustainable. The social housing system frequently selects sick people as priority tenants; this suggests that evaluating the impact of social housing requires a robust methodological design. Lawson and colleagues took the opportunity to evaluate the Scottish Governments progressive broad healthy public policy approach and make substantial investments in new social housing. Scottish housing associations approached their clientele, but only 46% of those approached agreed to participate in this study.2 Using a matched sample rather than randomisation inevitably resulted in a sample that was not matched on some key variables, such as age, …