Richard Summerhayes

Influence of socioeconomic and cultural factors on rural health.

OBJECTIVE To provide a framework for investigating the influence of socioeconomic and cultural factors on rural health. DESIGN Discussion paper. RESULTS Socioeconomic and cultural factors have long been thought to influence an individuals health. We suggest a framework for characterising these factors that comprises individual-level (e.g. individual socioeconomic status, sex, race) and neighbourhood-level dimensions (population composition, social environment, physical environment) operating both independently and through interaction. Recent spatial research suggests that in rural communities, socioeconomic disadvantage and indigenous status are two of the greatest underlying influences on health status. However, rural communities also face additional challenges associated with access to, and utilisation of, health care. The example is given of procedural angiography for individuals with an acute coronary event. CONCLUSIONS Socioeconomic and cultural factors specific to rural Australia are key influences on the health of residents. These range from individual-level factors, such as rural stoicism, poverty and substance use norms, to neighbourhood-level social characteristics, such as lack of services, migration out of rural areas of younger community members weakening traditionally high levels of social cohesion, and to environmental factors, such as climate change and access to services.

Socioeconomic and maternal determinants of small-for-gestational age births: patterns of increasing disparity

Objective. To better characterize the relation between socioeconomic disadvantage and small‐for‐gestational age births (SGA). Design. Analysis of data from a mandatory population‐based surveillance system. Setting. Public or private hospitals and at home. Population. All 877,951 singleton births occurring in New South Wales, Australia, between 1994 and 2004. Methods. Multilevel models were developed to determine the factors associated with babies weighing less than the 3rd percentile for gestation and gender. Main outcome measures. Odds of SGA. Results. The risk of SGA increased with increasing socioeconomic disadvantage. Smoking accounted for approximately 40% of the increased risk associated with socioeconomic disadvantage, and delayed antenatal care approximately 5%. While the absolute rate of SGA remained stable over the study period, the odds of SGA in mothers living in the most disadvantaged areas compared to those in the least disadvantaged areas increased from approximately 1.7 to 2.2. This trend persisted after accounting for maternal smoking. The risk of SGA over this period also increased in mothers commencing antenatal care after the first trimester. After accounting for smoking, socioeconomic disadvantage and clinical conditions, mothers under 21 years of age were at reduced risk of SGA, but mothers over 35 were at increased risk. Conclusions. Socioeconomic disadvantage remains one of the dominant determinants of SGA, even in a developed country with universal insurance. This relation appears to be strengthening. Smoking patterns, inadequate antenatal care and clinical conditions partially account for this association and trend, however, most is mediated by other factors.

Socioeconomic disadvantage and acute coronary events: a spatiotemporal analysis

Background: The associations between socioeconomic disadvantage and ischemic heart disease are not well understood. We explore the relationship between socioeconomic factors and acute coronary events using spatiotemporal analysis. Methods: We studied all deaths from acute myocardial infarction and hospital admissions for acute coronary syndrome and related revascularization procedures for the state of New South Wales, Australia, from 1996 through 2002. We used conditional autoregressive models to describe how characteristics of subjects’ place of residence (socioeconomic disadvantage, proportion of the population of indigenous background, and metropolitan versus nonmetropolitan area) influenced admissions and mortality. Results: There were 32,534 deaths due to acute myocardial infarction and 129,045 admissions for acute coronary syndrome. We found a relationship between increasing socioeconomic disadvantage and mortality (unadjusted relative risk for highest quartile of disadvantage relative to lowest = 1.40; 95% confidence interval = 1.27–1.54) as well as admissions (1.41; 1.28–1.55). After accounting for admission rates, socioeconomic disadvantage was associated with lower rates of angiography (0.75; 0.63–0.88) and interventional angiography (0.70; 0.56–0.85). After adjusting for socioeconomic disadvantage, areas with higher proportions of the population identified as indigenous had higher rates of admission and mortality, while residency in the state capital was associated with higher admission rates and more interventional angiography. After accounting for admission rates, the association of socioeconomic disadvantage with mortality was reduced. Conclusions: Socioeconomic disadvantage increases both the risk of acute coronary syndrome and related mortality. A contributing factor appears to be a reduced chance of receiving appropriate care. Regions with a higher proportion of indigenous residents show risk beyond the effects of general socioeconomic disadvantage, while residents of metropolitan communities had increased utilization of more recent interventions.

Spatio-temporal variation in trihalomethanes in New South Wales

AIM This paper describes the spatio-temporal variation of trihalomethanes in drinking water in New South Wales, Australia from 1997 to 2007 METHOD We obtained data on trihalomethanes (THMs) from two metropolitan and 13 rural water utilities and conducted a descriptive analysis of the spatial and temporal trends in THMs and the influence of season and drought. RESULTS Concetrations of monthly THMs in the two metropolitan water utilities of Sydney/Illawarra (mean 66.8 μg/L) and Hunter (mean 62.7 μg/L) were similar compared to the considerable variation between rural water utilities (range in mean THMs: 14.5-330.7 μg/L). Chloroform was the predominate THM in two-thirds of the rural water utilities. Higher concentrations of THMs were found in chlorinated water distribution systems compared to chloraminated systems, and in distribution systems sourced from surface water compared to ground water or mixed surface and ground water. Ground water sourced supplies had a greater proportion of brominated THMs than surface water sourced supplies. There was substantial variation in concentration of THMs between seasons and between periods of drought or no drought. There was a moderate correlation between heavy rainfall and elevated concentrations of THMs. CONCLUSION There is considerable spatial and temporal variation in THMs amongst New South Wales water utilities and these variations are likely related to water source, treatment processes, catchments, drought and seasonal factors.

Small area estimation of sparse disease counts using shared component models-application to birth defect registry data in New South Wales, Australia

In the field of disease mapping, little has been done to address the issue of analysing sparse health datasets. We hypothesised that by modelling two outcomes simultaneously, one would be able to better estimate the outcome with a sparse count. We tested this hypothesis utilising Bayesian models, studying both birth defects and caesarean sections using data from two large, linked birth registries in New South Wales from 1990 to 2004. We compared four spatial models across seven birth defects: spina bifida, ventricular septal defect, OS atrial septal defect, patent ductus arteriosus, cleft lip and or palate, trisomy 21 and hypospadias. For three of the birth defects, the shared component model with a zero-inflated Poisson (ZIP) extension performed better than other simpler models, having a lower deviance information criteria (DIC). With spina bifida, the ratio of relative risk associated with the shared component was 2.82 (95% CI: 1.46-5.67). We found that shared component models are potentially beneficial, but only if there is a reasonably strong spatial correlation in effect for the study and referent outcomes.

Colon and rectal cancer incidence and water trihalomethane concentrations in New South Wales, Australia

BackgroundThere is evidence, although inconsistent, that long term exposure to disinfection by products (DBPs) increases the risk of bowel cancer. No study has been conducted in Australia to examine this association and due to difference in the methods of disinfection the risk can vary across geographical regions and. This study was conducted to analyse the association of trihalomethanes (THMs) in water with colon and rectal cancer in NSW Australia.MethodsAverage yearly concentrations of total and individual species of THMs were obtained for 50 local government areas (LGAs). Indirectly-standardized incidence rates of colon and rectal cancers in LGAs for the period 1995 to 2001 were regressed against mean THM concentrations lagged five years, adjusting for socioeconomic status, high risk drinking, smoking status, usual source of water and year of diagnosis, including local and global random effects within a Bayesian framework. The incidence rate ratios (IRRs) for an interquartile range (IQR) increase in THMs were estimated.ResultsUsing five year lag of exposure there was a positive association between bromoform concentration and CRC in men (IRR = 1.025, 95% CI 1.010, 1.040) but not in women (IRR = 1.003, 95% CI 0.987, 1.018). The association in men was mainly found in colon cancer with bromoform (IRR = 1.035, 95% CI 1.017, 1.053). There was no appreciable association of colorectal cancer with other species of THMs. Sensitivity analyses did not materially change the associations observed.ConclusionA positive association was observed between colon cancer and water bromoform concentrations in men. Given the potential population impact of such an association, further research into the relationship between THMs, particularly brominated species, and colorectal cancer is warranted.