Cancer survival in New Zealand: ethnic, social and geographical inequalities.

This study investigated the combined effects of ethnicity, deprivation and geographical access to health services on the likelihood of survival from a range of common cancers in New Zealand. Individual cancer registry records of 99,062 cases of melanoma, colorectal, lung, breast and prostate cancers diagnosed in the period 1994-2004 were supplemented with small area information on social deprivation and estimates of travel time to the nearest primary care and cancer centre. Logistic regression was used to identify the variables associated with advanced extent of the disease at diagnosis. Adverse influences on survival were investigated using Cox proportional hazards models. Controlling for age and gender, Maori and Pacific peoples' ethnicity was strongly associated with poorer survival, partly because ethnicity was also linked to the likelihood of advanced disease at diagnosis. Living in a deprived area was related to later stage presentation and poorer survival of people with melanoma, but there was no other evidence that living in a deprived area or in a remote location were associated with later stage presentation. Some disease-specific trends in survival were observed. Colorectal and lung cancers were more likely to be fatal for people living in deprived areas, survival from prostate cancer was poor for men living remote from primary care, and people with colorectal, breast and prostate cancers had adverse survival chances if they lived distant from a cancer centre.

The influence of road curvature on fatal crashes in New Zealand.

Bends in roads can cause crashes but a recent study in the UK found that areas with mostly curved roads had lower crash rates than areas with straighter roads. This present study aimed to replicate the previous research in a different country. Variations in the number of fatal road crashes occurring between 1996 and 2005 in 73 territorial local authorities across New Zealand were modelled against possible predictors. The predictors were traffic flow, population counts and characteristics, car use, socio-economic deprivation, climate, altitude and road characteristics including four measures of average road curvature. The best predictors of the number of fatal crashes on urban roads, rural state highways and other rural roads were traffic flow, speed limitation and socio-economic deprivation. Holding significant factors constant, there was no evidence that TLAs with the most curved roads had more crashes than elsewhere. Fatal crashes on urban roads were significantly and negatively related to two measures of road curvature: the ratio of road length to straight distance and the cumulative angle turned per kilometre. Weaker negative associations on rural state highways could have occurred by chance. These results offer limited support to the suggestion that frequently occurring road bends might be protective.

Modifiable neighbourhood units, zone design and residents' perceptions.

Neighbourhood effects on health are partly determined by the way the neighbourhoods are defined (the modifiable areal unit problem), but few studies of place effects have incorporated alternative sets of areal units. This study compared computer-generated zones with areal units identified subjectively by local government officers as communities in the city of Bristol, UK. Automated zone design came close to replicating the subjective communities when the balance of objectives and boundary constraints was adjusted. The set of subjective community areas was compared with automated zone designs, which maximized the homogeneity of a social factor (deprivation) and an environmental factor (housing type), at three different geographical scales, with average populations of 2500, 3700 and 7500. All sets of areas were then matched against the neighbourhood perceptions and social behaviour reported by residents, measured as part of the Avon Longitudinal Study of Parents and Children (ALSPAC). Neighbourhood perceptions and social behaviour varied mostly between individuals, but there were significant small differences between all sets of areas. The neighbourhood perceptions of residents were found to match the areas identified by automated zone design as well as they matched the subjectively defined communities, suggesting that the neighbourhoods identified by experts were not more real to residents than synthetic areas. Differences in perceptions could be explained by variations in social and housing conditions at the very local scale of enumeration districts, with populations of about 500. The neighbourhoods with meaning for residents therefore appeared to be much smaller areas than those typically investigated in geographical studies of health.

The index of multiple deprivation 2000 access domain: a useful indicator for public health?

The access domain of the UK index of multiple deprivation (IMD) 2000 was designed to identify populations in small areas with poor geographical access to certain local key services. The measure is a composite of straight line distances to post offices, large food shops, primary schools and general practice surgeries for population sub-groups. Using the region of East Anglia as a case study area, this research evaluated the utility of the IMD2000 as an indicator of access to primary care. IMD2000 access scores for electoral wards were compared with a range of more detailed indicators of travel times and bus availability for visiting a general practitioner generated in a geographical information system (GIS). A range of easy-to-calculate surrogate variables was developed and tested as possible candidates to improve the explanatory power of the IMD2000 access score. The access domain was negatively correlated with the other five deprivation domains that comprise the overall index, suggesting that access should not be combined with the other measures of deprivation into a composite single score. The access domain was also found to predict access to primary care only with moderate accuracy. Two additional indicators of accessibility calculated in a GIS (road kilometres per thousand population and the presence of a major road in each ward) were found to add slightly to the power of the index. The predictive power of the index was best in urban areas, although it is in rural areas that access to primary care is a more important public health issue. The IMD2000 should be therefore used with caution as a measure of health service accessibility in rural areas.

Car travel time and accessibility by bus to general practitioner services: a study using patient registers and GIS.

Accessibility to general practitioner (GP) surgeries was investigated in a population study of East Anglia (Cambridgeshire, Norfolk and Suffolk) in the United Kingdom. Information from patient registers was combined with details of general practitioner surgery locations, road network characteristics, bus routes and community transport services, and a geographical information system (GIS) was used to calculate measures of accessibility to surgeries by public and private transport. Outcome measures included car travel times and indicators of the extent to which bus services could be used to visit GP surgeries. These variables were aggregated for wards or parishes and then compared with socio-economic characteristics of the populations living in those areas. The results indicated that only 10% of residents faced a car journey of more than 10 min to a GP. Some 13% of the population could not reach general medical services by daily bus. For 5% of the population, the car journey to the nearest surgery was longer than 10 min and there was no suitable bus service each weekday. In the remoter rural parishes, the lowest levels of personal mobility and the highest health needs indicators were found in the places with no daytime bus service each weekday and no community transport. The overall extent of accessibility problems and the existence of inverse care law effects in some rural localities have implications for the NHS, which aims to provide an equitable service to people wherever they live. The research also demonstrates the potential of patient registers and GIS as research and planning tools, though the practical difficulties of using these data sources and techniques should not be underestimated.