Amyotrophic lateral sclerosis in Lancashire and South Cumbria, England, 1976-1986. A geographical study.

An attempt was made to identify all patients presenting with amyotrophic lateral sclerosis (ALS) during a 10-year period in Lancashire and South Cumbria, England. An analysis of their place of residence was made using the postal code. This was used to allocate each patient to an electoral ward. Using such small areal units, it was found that more cases of ALS had arisen than would have been expected by chance in several wards during the study period. Although the actual number of wards showing this effect was probably not increased, the significance levels suggest that the disease may not show a random geographical distribution. No evidence of clustering of year of birth was found. These findings indicate the need for further work seeking geographical clusters of ALS and are discussed in relation to current etiological hypotheses of the disease.

Do new cases of rheumatoid arthritis cluster in time or in space?

OBJECTIVES: To examine for evidence of clustering in time, in space and in space/time in the occurrence of rheumatoid arthritis (RA). SETTING: A population-based incidence register of RA in the East Anglian region of the UK: population size 413,000. SUBJECTS: In all 687 new cases of inflammatory joint disease registered between 1 January 1990 and 31 December 1994 were studied. Population data were obtained from postcode areas by age and sex. ANALYSIS: Time trend analysis was conducted over the first 36 months and observed and expected distributions compared. Spatial clustering was based on comparison of observed distribution using map grid references to random expectation based on simulation. A similar procedure was undertaken for time/space clustering. RESULTS: There was no evidence of a time trend. There was only modest evidence of spatial clustering with non-random distribution observed in one area but there was no evidence of time/space clustering. CONCLUSION: Although a viral aetiology is the strongest candidate for RA, no evidence of a localized event in time was associated with disease development in this population.

Can physical trauma cause breast cancer?

The objective of this study is to explore the effect of lifestyle on the risk of invasive breast carcinoma in women aged 50-65 years. A case-control study using a questionnaire and a semi-structured interview. Cases (n = 67) and controls (n = 134) were closely matched on known risk factors for breast cancer including age, family history, age at menarche, parity, age at first birth and menopausal status. Controls were chosen from a pool of 5600 women who attended for breast screening and filled in a questionnaire giving details to allow matching with cases. The study took place at the North Lancashire Breast Screening Service. Women were aged 50-65 years and presented with breast cancer or attended for breast screening. Women with breast carcinoma were more likely to report physical trauma to the breast in the previous 5 years than were the controls (odds ratio (OR) 3.3, 95% confidence interval (CI) 1.3-10.8, P < 0.0001). There were no significant differences in a wide range of other lifestyle indicators including factors relevant to social class, education, residence, smoking and alcohol consumption. In conclusion, recall bias is an unlikely explanation for these results in view of the nature and severity of physical trauma. Models of epithelial cell generation indicate that a causal link between physical trauma and cancer is plausible. A latent interval between cancer onset and presentation of under 5 years is also plausible. The most likely explanation of the findings is that physical trauma can cause breast cancer.

Respiratory health effects of industrial air pollution: a study in east Lancashire, UK.

STUDY OBJECTIVE: To determine whether there was a higher incidence of respiratory ill health in children living near to a cement works than in those from a different area, and if so whether the higher incidence was due to the use of a hazardous waste-derived fuel at the works. STUDY DESIGN: A sample of the population of children living near the cement works (the study area) was compared with a sample of children living between 9 and 19 km away from the site (the control area). SETTING: The cement works is located on the north eastern edge of a small rural town in east Lancashire. METHODS: Data were collected via the use of a health questionnaire. This was distributed through selected primary schools to families who had one or more children of primary school age (5-11 years). MAIN RESULTS: The study and control populations were comparable in terms of response rates, gender, and socioeconomic indicators. There was no significant difference in the incidence of asthma (as diagnosed by a general practitioner) between the two areas when adjustment for hayfever was made. The incidence of sore throat was significantly higher in the case area, a difference not explained by other factors. For two other non-specific indicators of respiratory health (blocked nose and sore eyes) there was a significantly higher incidence in the study area, although hayfever and mould were also significant influences. CONCLUSIONS: The results indicated that certain non-specific health indicators were more common in the children living near a cement works. This excess may be due to exposure to emissions from the site. However, it is not possible to draw firm conclusions because there are no epidemiological data predating the use of the hazardous waste derived fuel.

Immunization against whooping cough in Salford: a spatial analysis.

The decline in pertussis (whooping cough) immunization in the 1970s is related to public concern about the safety of the vaccine. The debates about its safety and effectiveness and the impact of vaccination on notifications are reviewed. A study is made of spatial variations in vaccine uptake within the metropolitan district of Salford, Greater Manchester, using data available at ward level. Salford as a whole has one of the lowest rates of uptake in the North Western Regional Authority, which itself has the lowest uptake in the country. Variations from ward to ward are noted and an attempt is made to account for these using Poisson regression. Both the number of children being immunized against pertussis and the number receiving diphtheria and tetanus vaccine (but foregoing the pertussis component) are used as dependent variables. Of the explanatory variables social class proves a useful predictor. However, the analysis is an ecological one and further work is called for at the scale of individual clinics in order to investigate health worker and parental attitudes and the accessibility constraints felt by those responsible for bringing children to clinics.

Interactive spatial data analysis in medical geography.

Interactive spatial data analysis involves the use of software environments that permit the visualization, exploration and, perhaps, modelling of geographically-referenced data. Such systems are of obvious value in epidemiological research, both of an environmental and geographical nature. There is an increasing number of such software environments available on a variety of platforms and operating systems. This paper considers the use of the proprietary Geographical Information System, ARC/INFO, in a spatial analysis context, showing how the spatial analytic tools that may be added to it can be exploited by geographical epidemiologists; such tools include those for modelling possible raised incidence of disease around suspected sources of pollution. The paper also reviews the use of systems such as S-Plus and XLISP-STAT, statistical programming environments to which spatial analysis functions or libraries may be added. The use of INFO-MAP, a system designed to aid in the teaching of interactive spatial data analysis, is also highlighted. The various software environments are illustrated with reference to examples concerned with: clustering of childhood leukaemia in part of Lancashire, England; Burkitt's lymphoma in Uganda; larynx cancer in Lancashire; and childhood mortality in Auckland, New Zealand.

The geography of survival after surgery for colo-rectal cancer in southern England.

This study investigates variations in survival following surgery for colo-rectal cancer in the Wessex region (part of southern England), using 5147 cases diagnosed between 1 September 1991 and 31 August 1995. Survival curve estimation by life tables and Cox's proportional hazards model were used to examine geographical variation in cancer survival, with a specific focus on distance between place of residence and treatment centre, and district of treatment. We also consider whether area deprivation has an impact on survival. In seeking to answer these questions we control for possible confounders, including: age, gender, site of tumour, stage of disease at operation, hospital size and surgery type (whether elective or non-elective). District of treatment, distance and deprivation all show a relationship to outcome using survival curves, but when adjusting for other covariates using the Cox model, and considering deaths from all causes, only district of treatment was a very significant covariate (p < 0.0001). Distance, deprivation, and gender were only weakly significant (p < 0.10). Considering only deaths related to operation (within 30 days) district of treatment remained significant, but while distance had some effect on outcome, deprivation and gender ceased to be significant covariates. There is some evidence that those who live furthest from centres of treatment have the worst outcomes but the 'geography of survival' manifests itself more through where patients are treated than through area (deprivation) effects or relative location. The results have important policy implications, as they show variations among treatment centres having controlled for potentially confounding factors.

Do area-level population change, deprivation and variations in deprivation affect individual-level self-reported limiting long-term illness?

A previous study showed that variations in deprivation within small localities in England and Wales influenced the rates of self-reported limiting long-term illness, controlling for overall levels of deprivation. These results suggest that while morbidity is related to overall levels of material deprivation, the distribution of resources within small areas have a significant effect on health outcomes. However, it is possible that these area effects become redundant once individual-level characteristics are accounted for. This analysis examines whether area-level deprivation and variations in deprivation are significant indicators of individual-level limiting long-term illness, once individual characteristics have been accounted for.

The effect on morbidity of variability in deprivation and population stability in England and Wales: an investigation at small-area level.

We seek to determine whether variability in deprivation at small area level, and population stability, influence standardised morbidity ratios in England and Wales. A regression analysis was conducted with data from the 1991 British Census, in order to explain variation in morbidity. Both an area deprivation score (for electoral wards) and the within-area variability of deprivation scores were examined as possible determinants of morbidity (self-reported, limiting, long-term illness). Particular attention was focused on a spatially-sensitive measure of the variability of deprivation scores within a wider 'locality'. There was a significant, positive relationship between age-standardised limiting, long-term illness and deprivation. The variation in area deprivation scores within the small areas themselves was also significant and positive. However, the variation in deprivation scores calculated for both an electoral ward and its contiguous neighbours (the locality) was slightly more significant. Areas with higher relative levels of in-migration also had significantly lower standardised morbidity ratios. Multivariate models showed that the deprivation score, the variation in deprivation scores for the broader locality, and the measure of migration, were all significant in combination. Residual analysis showed that many areas in London had lower levels of morbidity than expected, while electoral wards in the coal mining valleys of South Wales had higher levels than expected. We conclude that, for small areas (wards) in England and Wales, morbidity is related to deprivation, variation in deprivation within and surrounding each area, and the proportion of the population that are migrants. Variations in deprivation influence standardised morbidity rates, and policies which widen inequalities will influence health outcomes. Resource allocation based simply on measures of deprivation, which ignore population change within the area and variations in deprivation in the locality, may be inefficient.

Congenital malformations in the Fylde region of Lancashire, England 1957-1973.

This paper uses data collected by a consultant paediatrician to examine variations in the prevalence of neural tube and cardiovascular malformations within the Fylde region of North West England. Results at the district scale indicate contrasts in the geographical distributions of the two classes of malformation and these are then further assessed via a case-control study which standardises for factors such as date of conception, age of mother and parity. The results of this study suggest that there were wards in Blackpool and Fleetwood with unusually high prevalences of neural tube defects. Further research is being undertaken to identify the causes of these concentrations.

Modelling exposure opportunities: estimating relative risk for motor neurone disease in Finland.

This paper addresses the issues surrounding an individual's exposure to potential environmental risk factors, which can be implicated in the aetiology of a disease. We hope to further elucidate the 'lag' or latency period between the initial exposure to potential pathogens and the physical emergence of the disease, with specific reference to the rare neurological condition, motor neurone disease (MND), using a dataset obtained from the Finnish Death Certificate registry, for MND deaths between the period 1985-1995. A space-time approach is adopted, whereby patterns in both time and space are considered. No prior assumptions about the aetiology of MND are adopted. By using methods for the analysis of point processes, which preserve the continuous nature of the data, we resolve some of the problems of analysis that are often based on arbitrary areal units, such as postcode boundaries, or political boundaries. We use kernel estimation to model space-time patterns. Raised relative risk is assessed by adopting appropriate adjustments for the underlying population at risk, with the use of controls. Significance of the results is assessed using Monte Carlo simulation, and comparisons are made with results obtained from Openshaw's geographical analysis machine (GAM). Our results demonstrate the utility of kernel estimation as a visualisation tool. Small areas of elevated risk are identified, which need to be more closely examined before any firm conclusions can be drawn. We highlight a number of issues concerning the inadequacies of the data, and possibly of the techniques themselves.

Impact of community neonatal services: a multicentre survey.

OBJECTIVES: To explore the impact of a community neonatal service on high risk infant survivors in the first year of life. DESIGN: Retrospective multicentre survey. Postal questionnaires were sent to selected parents. SETTING: Thirty two neonatal units in England and Wales. INCLUSION CRITERIA: infants over 12 months of age with birth weight < or =1500 g, or who received level I intensive care for at least 48 hours. EXCLUSION CRITERIA: multiple births, infants who had died or had severe congenital abnormalities. A total of 3367 eligible infants were selected, and their parents were sent a questionnaire; 65% responded. MAIN OUTCOME MEASURES: Length of stay on the neonatal unit from birth to initial discharge. Readmission to hospital during the first year of life. RESULTS: The median length of stay in units with a community neonatal service was 35 days compared with 37 days in units without. When adjusted for infant and parent characteristics, the median length of stay was reduced by 12.6% where a community neonatal service was provided (95% confidence interval 5.3% to 19.3%). The readmission rates were 44.6% in units with a community neonatal service and 43.5% in units without. There was no significant reduction in the adjusted odds of readmission. CONCLUSIONS: The retrospective nature of this study means that these findings cannot be definitely attributed to the presence of a community neonatal service. However, the results suggest that community neonatal services may reduce the length of stay without any subsequent increase in readmission.

Variations in use of cardiac services in England: perceptions of general practitioners, general physicians and cardiologists.

OBJECTIVE: To explain why those who live some distance from tertiary cardiac centres make less use of coronary angiography and revascularisation than those who live close by, and why people living in particular wards within certain districts make less use of services than might be expected from their level of need. METHOD: Semi-structured interviews with 24 general practitioners (GPs) in two English health districts (Morecambe Bay and East Lancashire), five general physicians working in district general hospitals, and four interventional cardiologists working in tertiary centres. Transcripts of audiotape recordings were analysed using the constant comparative method. RESULTS: Those living far from tertiary centres are usually referred to general physicians before they are referred for angiography. The general physicians tend to be more conservative in their approach to treatment than interventional cardiologists. GPs working near tertiary centres are able to refer directly to interventional cardiologists. There are also logistical and economic reasons for inequitable use of services. Some GPs perceived that patients of South Asian descent undergo fewer investigations than might be expected because of communication or other difficulties. CONCLUSION: Use of cardiac services would be more equitable if there were interventional cardiologists based in district general hospitals who could perform angiograms for their own patients in the tertiary centres. Patients might also benefit in angiograms could be conducted in selected district general hospitals. Further qualitative research, involving both doctors and patients, is needed to explore other reasons for relatively low rates of investigation and revascularisation in certain groups of patients.

The relationship between socio-demographic characteristics and dental health knowledge and attitudes of parents with young children.

OBJECTIVE: To determine if parental socio-demographic characteristics are associated with dental knowledge and attitude. DESIGN: A questionnaire survey of 500 consecutive parents with children aged approximately 8-months, attending clinics in 1999/2000, in Burnley, Pendle and Rossendale, for health visitor distraction-hearing tests. OUTCOME MEASURES: Scores were obtained for dental knowledge and attitudes. The socio-demographic variables of parental ethnicity, age, education and area of residence were used to determine any associations. RESULTS: Parental age ranged between 16-46 years. Child age ranged between 7-11 months. Significant differences were detected for parental dental knowledge according to ethnicity (P = 0.003), educational status (P = 0.000), and area of residence (P = 0.016). Significant differences were also found in dental attitudes; ethnicity (P = 0.000), educational status (P = 0.004) and area of residence (P = 0.005). Parental age was not significant for either knowledge or attitude. CONCLUSIONS: Lack of further education, being Asian and living in a deprived area means parents have less chances of high dental knowledge and positive dental attitudes.

Equity of access to adult hospice inpatient care within north-west England.

There is a growing debate about the question of equity of access to hospice and palliative care services. Even countries with relatively well developed palliative care systems are considered to have problems of access and inequity of provision. Despite these concerns, we still lack a relevant evidence base to serve as a guide to action. We present an analysis of access to adult hospice inpatient provision in the north-west region of England that employs Geographical Information Systems (GIS). Measures of the possible demand for, and supply of, hospice inpatient services are used to determine the potential accessibility of cancer patients, assessed at the level of small areas (electoral wards). Further, the use of deprivation scores permits an analysis of the equity of access to adult inpatient hospice care, leading to the identification of areas where additional service provision may be warranted. Our research is subject to a number of caveats--it is limited to inpatient hospice provision and does not include other kinds of inpatient and community-based palliative care services. Likewise, we recognise that not everyone with cancer will require palliative care and also that palliative care needs exist among those with nonmalignant conditions. Nevertheless, our methodology is one that can also be applied more generally.