The incidence of type 1 diabetes among children in Finland—rural–urban difference

Association of long-term environmental exposures in pregnancy and early life with islet autoimmunity development in children in Bavaria, Germany

OBJECTIVE

Incidence of early-onset type 1 diabetes (T1D) has been increasing worldwide. Only few studies examined the relationship between geographical environmental variation and T1D incidence or its presymptomatic stage of islet autoimmunity. Our study aimed to investigate the effect of long-term environmental exposures during pregnancy and early life on childhood islet autoimmunity.

RESEARCH DESIGN AND METHODS

We used data from the Fr1da cohort study which screened children aged 1.75-5.99 years for multiple islet autoantibodies in Bavaria, Germany between 2015 and 2019. We included 85,251 children with valid residential information. Daily averages for particulate matter with a diameter <2.5 μm, nitrogen dioxide, ozone, air temperature, and greenness were averaged for each zip-code or directly assigned to the addresses. The exposure windows included pregnancy, the first year and the first two years of life. Generalized additive models adjusting for individual and socioeconomic variables were used to investigate associations between environmental exposures and islet autoimmunity development.

RESULTS

Islet autoimmunity was diagnosed in 272 children. Colder air temperature during pregnancy was associated with developing islet autoimmunity at the address (per 2.2 °C decrease, Odds ratio (OR): 1.49; 95% Confidence interval (CI): 1.21-1.83) and zip-code level (per 2.4 °C decrease, OR: 1.31; 95% CI: 1.08-1.59). Using the addresses, significant associations were also observed during the first years of life.

CONCLUSION

In this study, children's residential exposure to lower levels of air temperature during pregnancy and early life increased the risk of islet autoimmunity before the age of six.

Models for predicting bulinids species habitats in southwestern Nigeria

Background

Schistosomiasis prevalence is high in southwestern Nigeria and planorbids of the genus Bulinus had been implicated in the transmission of the disease in the area. The knowledge of species distribution in relation to environmental variables will be auspicious in planning control strategies.

Methods

Satellite imagery and geographic information system (GIS) were used to develop models for predicting the habitats suitable for bulinid species. Monthly snail sample collection was done in twenty-three randomly selected water contact sites using the standard method for a period of two years. Remotely sensed variables such as Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) were extracted from Landsat TM, ETM⁺; Slope and Elevation were obtained from digital elevation model (DEM) while Rainfall was retrieved from European Meteorology Research Program. These environmental factors and snail species were integrated into QGIS to predict the potential habitats of different bulinid species using an exploratory regression model.

Results

The following environmental variables: flat-moderate slope (0.01–15.83), LST (21.1 °C-23.4 °C), NDVI (0.19–0.52), rainfall (> 1569.34 mm) and elevation (1–278 m) contributed to the model used in predicting habitat suitable for bulinids snail intermediate hosts. Exploratory regression models showed that LST, NDVI and slope were predictors of Bulinus globosus and Bulinus jousseaumei; elevation, LST, rainfall and slope were predictors of Bulinus camerunensis; rainfall, NDVI and slope were predictors of B. senegalensis while NDVI and slope were predictors of Bulinus forskalii in the area. Bulinids in the forskalii group showed clustering in middle belt and south. The predictive risk map of B. jousseaumei was similar to the pattern described for B. globosus, but with a high R-square value of 81%.

Conclusion

The predictive risk models of bulinid species in this study provided a robust output for the study area which could be used as base-line for other areas in that ecological zone. It will be useful in appropriate allocation of scarces resources in the control of schistosomiasis in that environment.

Land Cover of Early-Life Environment Modulates the Risk of Type 1 Diabetes

OBJECTIVE

Environmental microbial exposures have been implicated to protect against immune-mediated diseases such as type 1 diabetes. Our objective was to study the association of land cover around the early-life dwelling with the development of islet autoimmunity and type 1 diabetes to evaluate the role of environmental microbial biodiversity in the pathogenesis.

RESEARCH DESIGN AND METHODS

Association between land cover types and the future risk of type 1 diabetes was studied by analyzing land cover types classified according to Coordination of Information on the Environment (CORINE) 2012 and 2000 data around the dwelling during the first year of life for 10,681 children genotyped for disease-associated HLA-DQ alleles and monitored from birth in the Type 1 Diabetes Prediction and Prevention (DIPP) study. Land cover was compared between children who developed type 1 diabetes (n = 271) or multiple diabetes-associated islet autoantibodies (n = 384) and children without diabetes who are negative for diabetes autoantibodies.

RESULTS

Agricultural land cover around the home was inversely associated with diabetes risk (odds ratio 0.37, 95% CI 0.16-0.87, P = 0.02 within a distance of 1,500 m). The association was observed among children with the high-risk HLA genotype and among those living in the southernmost study region. Snow cover on the ground seemed to block the transfer of the microbial community indoors, leading to reduced bacterial richness and diversity indoors, which might explain the regional difference in the association. In survival models, an agricultural environment was associated with a decreased risk of multiple islet autoantibodies (hazard ratio [HR] 1.60, P = 0.008) and a decreased risk of progression from single to multiple autoantibody positivity (HR 2.07, P = 0.001) compared with an urban environment known to have lower environmental microbial diversity.

CONCLUSIONS

The study suggests that exposure to an agricultural environment (comprising nonirrigated arable land, fruit trees and berry plantations, pastures, natural pastures, land principally occupied by agriculture with significant areas of natural vegetation, and agroforestry areas) early in life is inversely associated with the risk of type 1 diabetes. This association may be mediated by early exposure to environmental microbial diversity.

Effects of family and neighborhood risks on glycemic control among young black adolescents with type 1 diabetes: Findings from a multi-center study

While individual and family risk factors that contribute to health disparities in children with type 1 diabetes have been identified, studies on the effects of neighborhood risk factors on glycemic control are limited, particularly in minority samples. This cross-sectional study tested associations between family conflict, neighborhood adversity and glycemic outcomes (HbA1c) in a sample of urban, young Black adolescents with type 1 diabetes(mean age = 13.4 ± 1.7), as well as whether neighborhood adversity moderated the relationship between family conflict and HbA1c. Participants (N = 128) were recruited from five pediatric diabetes clinics in two major metropolitan US cities. Diabetes-related family conflict was measured via self-report questionnaire (Diabetes Family Conflict Scale; DFCS). Neighborhood adversity was calculated at the census block group level based on US census data. Indictors of adversity were used to calculate a neighborhood adversity index (NAI) for each participant. Median family income was $25,000, suggesting a low SES sample. In multiple regression analyses, DFCS and NAI both had significant, independent effects on glycemic control (β = 0.174, P = 0.034 and β = 0.226 P = 0.013, respectively) after controlling for child age, family socioeconomic status and insulin management regimen. Tests of effects of the NAI and DFCS interaction on HbA1c found no significant moderating effects of neighborhood adversity. Even within contexts of significant socioeconomic disadvantage, variability in degree of neighborhood adversity predicts diabetes-related health outcomes in young Black adolescents with type 1 diabetes. Providers should assess social determinants of health such as neighborhood resources that may impact adolescents' ability to maintain optimal glycemic control.

Associations of area deprivation and urban/rural traits with the incidence of type 1 diabetes: analysis at the municipality level in North Rhine-Westphalia, Germany

AIM

To analyse the associations of area deprivation and urban/rural traits with the incidence of type 1 diabetes in the German federal state of North Rhine-Westphalia.

METHODS

Data of incident type 1 diabetes cases in children and adolescents aged <20 years between 2007 and 2014 were extracted from a population-based diabetes register. Population data, indicators of area deprivation and urban/rural traits at the municipality level (396 entities) were obtained from official statistics. Area deprivation was assessed in five groups based on quintiles of an index of multiple deprivation and its seven deprivation domains. Poisson regression accounting for spatial dependence was applied to investigate associations of area deprivation and urban/rural traits with type 1 diabetes incidence.

RESULTS

Between 2007 and 2014, 6143 incident cases were reported (99% completeness); the crude incidence was 22.3 cases per 100 000 person-years. The incidence decreased with increasing employment and environmental deprivation (relative risk of the most vs. the least deprived municipalities: 0.905 [95% CI: 0.813, 1.007] and 0.839 [0.752, 0.937], respectively) but was not associated with the composite deprivation index. The incidence was higher in more peripheral, rural, smaller and less densely populated municipalities, and the strongest association was estimated for the location trait (relative risk of peripheral/very peripheral compared with very central location: 1.231 [1.044, 1.452]).

CONCLUSIONS

The results suggest that the type 1 diabetes risk is higher in more remote, more rural, less densely populated and less deprived areas. Urban/rural traits were stronger predictors of type 1 diabetes risk than area deprivation indicators.

Prevalence and incidence of type 1 diabetes in the world: a systematic review and meta-analysis

Background: Diabetes is referred to a group of diseases characterized by high glucose levels in blood. It is caused by a deficiency in the production or function of insulin or both, which can occur because of different reasons, resulting in protein and lipid metabolic disorders. The aim of this study was to systematically review the prevalence and incidence of type 1 diabetes in the world. Methods: A systematic search of resources was conducted to investigate the prevalence and incidence of type 1 diabetes in the world. The databases of Medline (via PubMed and Ovid),ProQuest, Scopus, and Web of Science from January 1980 to September 2019 were searched to locate English articles. The located articles were screened in multiple levels of title, abstract,and full-text and final studies that met the inclusion criteria were retrieved and included in the study. Results: From 1202 located articles, 193 studies were included in this systematic review. The results of meta-analysis showed that the incidence of type 1 diabetes was 15 per 100,000 people and the prevalence was 9.5% (95% CI: 0.07 to 0.12) in the world, which was statistically significant. Conclusion: According to the results, the incidence and prevalence of type 1 diabetes are increasing in the world. As a result, insulin will be difficult to access and afford, especially in underdeveloped and developing countries.

Onset of type 1 diabetes mellitus in rural areas of the USA

BACKGROUND

In the USA, the epidemiologic features of type 1 diabetes are not well-defined across all 50 states. However, the advent of large nationwide insurance databases enables the investigation of where type 1 diabetes cases occur throughout the country.

METHODS

An integrated database from a large nationwide health insurer in the USA (Clinformatics Data Mart Database) was used, from 2001 to 2017. The database contained longitudinal information on approximately 77 million people.

RESULTS

The incidence of type 1 diabetes was greatest in areas of low population density across the 50 states. Individuals in the lowest population density areas had rates that were 2.28 times (95% CI 2.08 to 2.50) that of persons living in high-density areas. This association was consistent across various measures of rural status (p<0.001 for population density; p<0.001 for per cent rural as defined by the US Census Bureau; p=0.026 for farmland). The association between rural areas and the incidence of type 1 diabetes was evident across all four general regions of the USA.

CONCLUSIONS

The predilection of type 1 diabetes in rural areas provides clues to potential factors associated with the onset of this autoimmune disease.

Epidemiology of type 1 diabetes in Polish children: A multicentre cohort study

BACKGROUND

The incidence of childhood type 1 diabetes (T1D) varies greatly between populations, and the estimates and/or predictions of the rates would aid in adequate planning of health care resources. The study's aim was to assess the incidence of T1D in the paediatric population of eastern and central Poland.

METHODS

In this cohort study covering the period from January 2010 to December 2014, data were collected for children and adolescents below 18 years of age with newly diagnosed T1D living in eastern and central Poland. A total of 2174 children were included in the analysis. The population estimates were from the Central Statistical Office of Poland.

RESULTS

Overall, the annual incidence of T1D increased from 12.84/100,000 in 2010 to 18.46/100,000 in 2014 with the incidence rate (IR) ratio of 1.5 (an increase in the IR by 12.7% per year over 5 years). The lowest increase in the IR by 7.1% per year was seen in 15 to 17-year-olds. In the urban population (age 0-17 years), the overall incidence rate was significantly higher than in subjects from rural communities (P < .02). The incidence of T1D in rural areas was significantly higher (p = .004) in voivodeships of higher population density. Such dependence was not observed in urban areas.

CONCLUSIONS

The incidence of T1D in children living in eastern and central Poland increased 1.5-fold over the 5-year observation period with the highest rise in 10 to 14-year-olds and significantly higher rates in urban children compared with their peers living in rural areas.

Environmental Factors Associated with Type 1 Diabetes Development: A Case Control Study in Egypt

Uncertainty still exists regarding the role of some environmental risk in the development of type 1 diabetes mellitus (T1DM) both globally and in Egypt. The objective here was to explore the potential environmental risk factors associated with the development of T1DM among children in Egypt. A case-controlled study of 204 T1DM children and an equal number of age and sex-matched controls was conducted in Assiut, Egypt. Data regarding the parental, gestational, neonatal, and childhood possible risk factors for T1DM were evaluated. The final sex adjusted multivariable logistic regression model revealed that the risk for T1DM was significantly higher among rural residents (aOR = 2.03, 95% CI: 1.30-4.25), those with parental history of T1DM (aOR = 9.03, 95% CI: 1.02-83.32), birth through cesarean section (aOR = 2.13, 95% CI: 1.09-5.03), and having history of early introduction of cow milk in the first year of life (aOR = 19.49, 95% CI: 8.73-45.53). On the other hand, a protective effect was observed between at least six months' breastfeeding, vitamin D supplementation in the first year of life, high physical activity, and the development of T1DM. Educational programs should be adopted to improve awareness and knowledge of the parents to avoid the increased risk factors and encourage protective practices.

Reducing episodes of diabetic ketoacidosis within a youth population: a focus group study with patients and families

Background

Diabetic ketoacidosis (DKA) is the most common cause of morbidity and mortality for youth with type 1 diabetes mellitus (T1DM). This article reports qualitative data from focus groups with youth and parents of youth with T1DM on the barriers that they identify to DKA prevention and resources that may aid youth better manage their diabetes.

Methods

Four focus groups were held in three communities, two rural and one urban, in the Canadian province of Newfoundland and Labrador (NL) with adolescents and parents of youth with diabetes. Open-ended questions focused on knowledge of DKA, diabetes education, personal experiences with DKA, barriers to diabetes self-management, situations which put them at risk for DKA and resources that could be developed to aid youth in preventing DKA.

Results

There were 19 participants (14 parents and 5 youth). Participants identified factors which increased their risk of DKA as difficulty in distinguishing cases of DKA from other illnesses; variations in diabetes education received; information overload about their condition; the long period from initial diagnosis, when most education about the condition was received; and stress regarding situations where youth are not in the direct care of their parents. Participants from rural areas reported geographical isolation and lack of regular access to specialist health care personnel as additional barriers to better diabetes management.

Conclusions

The project identified barriers to DKA prevention for youth which were not previously identified in the medical literature, e.g., the stress associated with temporary guardians, risk of information overload at initial diagnosis and the long period from initial diagnosis when most diabetes education is received. Families from rural areas do report additional burdens, but in some cases these families have developed community supports to help offset some of these problems. Mobile and online resources, educational refreshers about DKA, concise resources for teachers and other temporary guardians, and DKA treatment kits for parents may help improve diabetes management and prevent future episodes of DKA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1358-7) contains supplementary material, which is available to authorized users.

Statistical Approaches Used to Assess the Equity of Access to Food Outlets: A Systematic Review

Background

Inequalities in eating behaviours are often linked to the types of food retailers accessible in neighbourhood environments. Numerous studies have aimed to identify if access to healthy and unhealthy food retailers is socioeconomically patterned across neighbourhoods, and thus a potential risk factor for dietary inequalities. Existing reviews have examined differences between methodologies, particularly focussing on neighbourhood and food outlet access measure definitions. However, no review has informatively discussed the suitability of the statistical methodologies employed; a key issue determining the validity of study findings. Our aim was to examine the suitability of statistical approaches adopted in these analyses.

Methods

Searches were conducted for articles published from 2000–2014. Eligible studies included objective measures of the neighbourhood food environment and neighbourhood-level socio-economic status, with a statistical analysis of the association between food outlet access and socio-economic status.

Results

Fifty-four papers were included. Outlet accessibility was typically defined as the distance to the nearest outlet from the neighbourhood centroid, or as the number of food outlets within a neighbourhood (or buffer). To assess if these measures were linked to neighbourhood disadvantage, common statistical methods included ANOVA, correlation, and Poisson or negative binomial regression. Although all studies involved spatial data, few considered spatial analysis techniques or spatial autocorrelation.

Conclusions

With advances in GIS software, sophisticated measures of neighbourhood outlet accessibility can be considered. However, approaches to statistical analysis often appear less sophisticated. Care should be taken to consider assumptions underlying the analysis and the possibility of spatially correlated residuals which could affect the results.

Epidemiology of childhood Type 1 diabetes in Taiwan, 2003 to 2008

AIMS

To report the annual incidence rate and the socio-demographic and clinical characteristics of childhood Type 1 diabetes in Taiwan in the period 2003-2008.

METHODS

A total of 1306 incident cases of childhood (0-14 years) Type 1 diabetes were identified from Taiwan's National Health Insurance claim datasets from the period 2003-2008. The temporal trend of the incidence rate of Type 1 diabetes and the features of hospitalizations in the first year after diagnosis were investigated. The associations of patient characteristics, child population density and the urbanization level of the residential areas with the risk of Type 1 diabetes were assessed using Poisson regression analysis.

RESULTS

The annual incidence rate was stable, irrespective of age and gender, with a mean annual incidence rate of 5.3 per 100 000 children. Girls were more likely than boys to develop Type 1 diabetes (6.0 vs 4.7 per 100 000 children) and the incidence rate increased with age. There was no apparent geographic variation in the incidence rates. Despite the 60% decrease in the rate of admission (from 11.0 to 5.8%) over the study period, ketoacidosis remained the major diabetes complication leading to admission for childhood Type 1 diabetes. The multivariate analysis suggested that female gender and older age were significant predictors of the incidence of Type 1 diabetes, whereas the population density of children and the urbanization levels of the residential areas were not.

CONCLUSIONS

Girls and older children should receive particular attention when formulating preventive strategies targeting Type 1 diabetes. Additionally, clinicians should still carefully optimize the management of children with Type 1 diabetes to further reduce the occurrence of ketoacidosis.

Epidemiology of childhood type 1 diabetes mellitus in Nile Delta, northern Egypt - a retrospective study

OBJECTIVE

The geographical incidence of type 1 diabetes mellitus (T1DM) varies widely worldwide. Both genetic and environmental factors have been implicated, although environmental factors are still speculative and elusive. More epidemiological studies are needed to uncover such factors. To date, there are no reported studies on the epidemiology of childhood T1DM in Nile Delta, Egypt. We aimed to define the incidence, prevalence and demographic characteristics of T1DM in children (0-18 years) living in the Nile Delta region, one of the most densely populated areas in Egypt.

METHODS

The study included all T1DM patients aged 0-18 years who lived in the Nile Delta region of Egypt and who were either diagnosed at or referred to Mansoura University Children's Hospital (MUCH) between 1 January 1994 and 31 December 2011. The hospital files of the patients were reviewed. General population data on the 0-18 year age group in the Nile Delta governorates were also presented.

RESULTS

From a total of 1600 T1DM patients, 891 (55.7%) were females (p=0.000) and 935 (58.4%) were from rural areas (p=0.000). Calculated age-adjusted incidence of T1DM in 1996, 2006 and 2011 were 0.7, 2.0 and 3.1/10(5)/year, respectively, while calculated age-adjusted prevalence of T1DM in the same years were 1.9, 15.5 and 26.8/10(5)/year, respectively. Patients presented most frequently in the 5-10 year age group (p<0.000) and in winter months (p=0.009).

CONCLUSION

In this first childhood T1DM epidemiology study in the Nile Delta region of Egypt, T1DM incidence and prevalence were found to show an increase over the past 18 years (1994-2011). Incidence and prevalence were higher in females and more cases were found to originate from rural areas.

Does farm environment protect against type 1 diabetes mellitus?

AIMS/HYPOTHESIS

Hygiene hypothesis has been shown valid in respect of allergies and asthma but has not been, however, sufficiently studied in relation to type 1 diabetes mellitus. This study investigates the effect of childhood farm environment on the prevalence of type 1 diabetes mellitus in Finnish children and young adults.

METHODS

Data come from a questionnaire study carried out in 2007 (N = 5805). Prevalence of type 1 diabetes mellitus was analysed according to the type of the rural exposure below the age of 18 years. Associations were estimated and tested using Bayesian methods.

RESULTS

Consistent suggestive evidence of the inverse association of childhood's farm environment with the occurrence of type 1 diabetes mellitus was shown, even though conclusive results were not reached.

CONCLUSION/INTERPRETATION

Exposure to a broad variety of non-pathogenic environmental microorganisms during childhood might have a protective effect on type 1 diabetes mellitus. Results clearly suggest that further research is well grounded with larger samples.

Modeling type 1 and type 2 diabetes mellitus incidence in youth: an application of Bayesian hierarchical regression for sparse small area data

Sparse count data violate assumptions of traditional Poisson models due to the excessive amount of zeros, and modeling sparse data becomes challenging. However, since aggregation to reduce sparseness may result in biased estimates of risk, solutions need to be found at the level of disaggregated data. We investigated different statistical approaches within a Bayesian hierarchical framework for modeling sparse data without aggregation of data. We compared our proposed models with the traditional Poisson model and the zero-inflated model based on simulated data. We applied statistical models to type 1 and type 2 diabetes in youth 10-19 years known as rare diseases, and compared models using the inference results and various model diagnostic tools. We showed that one of the models we proposed, a sparse Poisson convolution model, performed better than other models in the simulation and application based on the deviance information criterion (DIC) and the mean squared prediction error.

Bayesian analysis of the geographical variation of type 1 diabetes mellitus in under 15 yr olds in northeast Spain, 1991-2009

OBJECTIVE

High variability has been observed in type 1 diabetes mellitus (DM1) incidence rates (IRs) in childhood. The aim of this study was to characterize DM1 in Aragón and to identify variations in the geographical pattern by gender.

METHODS

A descriptive and ecological study was conducted to determine geographical variations in the DM1 incidence for the period 1991-2009. The source of information was the registry of DM1. To determine data completeness, a capture-recapture analysis was performed. Cases were georeferenced according to the Basic Healthcare Area (BHA) of residence. IRs for both genders, age group, 5 yr of diagnosis, and 95% confidence intervals (95% CIs) were calculated. Geographical pattern was studied applying Bayesian statistical model. The standardized incidence ratios (SIRs), smoothed SIR, and the posteriori risk probability (PRP) were represented cartographically for BHA stratified by gender.

RESULTS

The completeness was 93.5%. The global IR was 19.2 cases/10(5) person-years (95% CI: 17.6-20.8), boys 21.4 (95% CI: 19.0-23.8) and girls 16.8 (95% CI: 14.7-19.1). The age-specific rates were significantly lower in the 0-4 year age group with respect to the groups of 5-9 and 10-14 years. For boys, areas with a statistically significant excess of risk were found in the north [smoothed SIR: 118-167.9 and PRP of what the smoothed SIR would be greater than 100 (PRP) above 0.8] and below average risk in the south (smoothed SIR: 65.9-79.1 and PRP less than 0.2).

CONCLUSIONS

DM1 IR presented a north-south geographical pattern in boys. This pattern was not observed in girls or when both genders were considered together. Later studies should include gender as an essential variable.

Regional differences in incidence and clinical presentation of type 1 diabetes in children aged under 15 years in Croatia

AIM

To determine regional differences in the incidence, incidence trends, and clinical presentation of type 1 diabetes in children under the age of 15 years in Croatia in a 9-year period (1995-2003).

METHODS

We included the patients who had been diagnosed with the disease and had started the insulin treatment before they were 15 years old. Regional differences between eastern, central, and southern Croatia were observed. The gross incidence was expressed by the number of newly diagnosed type 1 diabetes patients in 100000 children of the same age and sex per year, ie, for the 0-14 age group, and for the 0-4, 5-9, and 10-14 subgroups.

RESULTS

The highest incidence was observed in southern Croatia (10.91 per 100000/y) and the lowest in central Croatia (8.64 per 100000/y), and in eastern Croatia the incidence was 8.93 per 100000/y. All three regions showed a growing incidence trend, which was significant only in eastern and southern Croatia. There was 35.9% of patients with diabetic ketoacidosis in eastern Croatia, 41.7% in central Croatia, and 31.28% in southern Croatia.

CONCLUSION

Croatian regions show differences in the incidence, incidence trends, and disease presentation of type 1 diabetes. A further follow-up is needed to establish whether the regional differences are a consequence of the population dynamics in the observed period or they will continue to exist, pointing to differences in environmental risk factors.

Benchmarking the location of health centers at Jeddah city: a GIS approach

Purpose

The purpose of this paper is to discuss a GIS application created for health care planning at Jeddah city, Saudi Arabia. The application covers important health care facilities planning issues including defining accessibility to health care facilities, identifying and classifying the distribution of health demand at Jeddah city and modeling spatial variation of patient locations.

Design/methodology/approach

In order to build this application, a geo‐database is created that covers points, lines and polygon features such as health care facility location, road network and population districts. In addition, raster surface models are produced using Kriging function which produces raster surfaces for predicting health demand values at the study area.

Findings

The outputs of this application can be used to help health care planners in evaluating the existing location of health care facilities and see if these locations are concentrated at certain city districts. In addition, local health planners can use the created models when deciding where to allocate a new health care facility at Jeddah city.

Originality/value

This application is considered as a spatial decision support system for health planners in Jeddah city. It can be used to define and evaluate location of health centers as well as to identify the spatial accessibility to health centers.

Low zinc in drinking water is associated with the risk of type 1 diabetes in children

AIM

To explore if drinking water may influence the development of type 1 diabetes in children, either via enterovirus spread via drinking water or quality of drinking water related to acidity or concentration of certain minerals.

METHODS

One hundred and forty-two families with a child with diabetes and who lived either in seven municipalities with a high annual diabetes incidence during 1977-2001 and in six municipalities with the lowest incidence during those 25 yr were asked to participate. Three hundred and seventy-three families in these communities were used as controls. The families filled a 200-mL plastic bottle with their tap drinking water and returned it by mail. The water samples were analyzed for pH, zinc, iron, nitrate, nitrite, nitrate-nitrogen and nitrite-nitrogen, and occurrence of enterovirus RNA.

RESULTS

Enterovirus RNA was not found in the tap water samples. The concentration of zinc, nitrate, and nitrate-nitrogen was lower in the municipalities with high incidence of type 1 diabetes. The water samples from families with a child with diabetes had lower concentration of zinc than water samples from control families.

CONCLUSION

Low zinc in drinking water is associated with the risk of developing type 1 diabetes during childhood. Enterovirus does not seem to be spread via drinking water in a country with modern water works.

Evaluating geographic variation in type 1 and type 2 diabetes mellitus incidence in youth in four US regions

We evaluated geographic variation in type 1 and type 2 diabetes mellitus (T1DM, T2DM) in four regions of the United States. Data on 807 incident T1DM cases diabetes and 313 T2DM cases occurring in 2002-03 in South Carolina (SC) and Colorado (CO), 5 counties in Washington (WA), and an 8 county region around Cincinnati, Ohio (OH) among youth aged 10-19 years were obtained from the SEARCH for Diabetes in Youth Study. Geographic patterns were evaluated in a Bayesian framework. Incidence rates differed between the study regions, even within race/ethnic groups. Significant small-area variation within study region was observed for T1DM and T2DM. Evidence for joint spatial correlation between T1DM and T2DM was present at the county level for SC (r(SC)=0.31) and CO non-Hispanic Whites (r(CO)=0.40) and CO Hispanics (r(CO)=0.72). At the tract level, no evidence for meaningful joint spatial correlation was observed (r(SC)=-0.02; r(CO)=-0.02; r(OH)=0.03; and r(WA=)0.09). Our study provides evidence for the presence of both regional and small area, localized variation in type 1 and type 2 incidence among youth aged 10-19 years in the United States.

The geoepidemiology of type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by absolute insulin deficiency resulting from the progressive immune-mediated destruction of pancreatic islet beta cells. It is thought to be triggered by as yet unidentified environmental factors in genetically susceptible individuals, the major genetic contribution coming from loci within the HLA complex, in particular HLA class II. The worldwide incidence of T1D varies by at least 100-fold, being highest in Finland and Sardinia (Italy) and lowest in Venezuela and China. The incidence has been increasing worldwide at an annual rate of approximately 3%. While genetic factors are thought to explain some of the geographic variability in T1D occurrence, they cannot account for its rapidly increasing frequency. Instead, the declining proportion of newly diagnosed children with high-risk genotypes suggests that environmental pressures are now able to trigger T1D in genotypes that previously would not have developed the disease during childhood. Although comparisons between countries and regions with low and high-incidence rates have suggested that higher socioeconomic status and degree of urbanization are among the environmental factors that play a role in the rising incidence of T1D, the findings are too inconsistent to allow firm conclusions. Morbidity and mortality as well as causes of death also show considerable geographic variation. While glycemic control has been identified as a major predictor of the micro- and macrovascular complications of T1D and shows considerable geographical variability, it does not appear to be the only factor involved in the regional differences in complication rates. The role of genetics in susceptibility to nephropathy, retinopathy and other diabetic complications largely remains to be explored.

Particulate air pollution and chronic ischemic heart disease in the eastern United States: a county level ecological study using satellite aerosol data

BACKGROUND

There are several known factors that cause ischemic heart disease. However, the part played by air pollution still remains something of a mystery. Recent attention has focused on the chronic effect of particulate matter on heart disease. Satellite-derived aerosol optical depth (AOD) was found to be correlated with PM2.5 in the eastern US. The objective of this study was to examine if there is an association between aerosol air pollution as indicated by AOD and chronic ischemic heart disease (CIHD) in the eastern US.

METHODS

An ecological geographic study method was employed. Race and age standardized mortality rate (SMR) of CIHD was computed for each of the 2306 counties for the time period 2003-2004. A mean AOD raster grid for the same period was derived from Moderate Resolution Imaging Spectrometer (MODIS) aerosol data and the average AOD was calculated for each county. A bivariate Moran's I scatter plot, a map of local indicator of spatial association (LISA) clusters, and three regression models (ordinary least square, spatial lag, and spatial error) were used to analyze the relationship between AOD and CIHD SMR.

RESULTS

The global Moran's I value is 0.2673 (p = 0.001), indicating an overall positive spatial correlation of CIHD SMR and AOD. The entire study area is dominated by spatial clusters of AOD against SMR (high AOD and high SMR in the east, and low AOD and low SMR in the west) (permutations = 999, p = 0.05). Of the three regression models, the spatial error model achieved the best fit (R2 = 0.28). The effect of AOD is positive and significant (beta = 0.7774, p = 0.01).

CONCLUSION

Aerosol particle pollution has adverse effect on CIHD mortality risk in the eastern US. High risk of CIHD mortality was found in areas with elevated levels of outdoor aerosol air pollution as indicated by satellite derived AOD. The evidence of the association would support targeting of policy interventions on such areas to reduce air pollution levels. Remote sensing AOD data could be used as an alternative health-related indictor of air quality.

Spatial analysis of MODIS aerosol optical depth, PM2.5, and chronic coronary heart disease

Background

Numerous studies have found adverse health effects of acute and chronic exposure to fine particulate matter (PM_2.5). Air pollution epidemiological studies relying on ground measurements provided by monitoring networks are often limited by sparse and unbalanced spatial distribution of the monitors. Studies have found correlations between satellite aerosol optical depth (AOD) and PM_2.5 in some land regions. Satellite aerosol data may be used to extend the spatial coverage of PM_2.5 exposure assessment. This study was to investigate correlation between PM_2.5 and AOD in the conterminous USA, to derive a spatially complete PM_2.5 surface by merging satellite AOD data and ground measurements based on the potential correlation, and to examine if there is an association of coronary heart disease with PM_2.5.

Results

Years 2003 and 2004 daily MODIS (Moderate Resolution Imaging Spectrometer) Level 2 AOD images were collated with US EPA PM_2.5 data covering the conterminous USA. Pearson's correlation analysis and geographically weighted regression (GWR) found that the relationship between PM_2.5 and AOD is not spatially consistent across the conterminous states. The average correlation is 0.67 in the east and 0.22 in the west. GWR predicts well in the east and poorly in the west. The GWR model was used to derive a PM_2.5 grid surface using the mean AOD raster calculated using the daily AOD data (RMSE = 1.67 μg/m³). Fitting of a Bayesian hierarchical model linking PM_2.5 with age-race standardized mortality rates (SMRs) of chronic coronary heart disease found that areas with higher values of PM_2.5 also show high rates of CCHD mortality: = 0.802, posterior 95% Bayesian credible interval (CI) = (0.386, 1.225).

Conclusion

There is a spatial variation of the relationship between PM_2.5 and AOD in the conterminous USA. In the eastern USA where AOD correlates well with PM_2.5, AOD can be merged with ground PM_2.5 data to derive a PM_2.5 surface for epidemiological study. The study found that chronic coronary heart disease mortality rate increases with exposure to PM_2.5.

Variations in incidence of type 1 diabetes in different municipalities of stockholm

This article reports a test of the hypothesis that municipalities within the County of Stockholm have varying incidence rates of type 1 diabetes (T1D), suggesting a strong etiologic environmental component to the disease. The study group included T1D patients in the age group from birth to 18 years who were diagnosed each year from 20 municipalities in Stockholm County during the 1990-2003. Specific incidence rates by age, sex, and socioeconomic characteristics (income level, proportion of taxpayers, proportion of foreigners, population density and green cover) were estimated annually together with age standardization. chi(2) analyses were used for the statistical assessment of variability in incidence. During the study period, 733 newly diagnosed T1D patients aged 0-18 years were recorded from the 20 municipalities under study. The overall age-standardized incidence in these 20 municipalities was 24.38 (22.65-26.21) per 100,000, with 45.35 (32.08-62.29) as highest and 13.41 (9.53-18.35) as lowest estimated incidence. For all socioeconomic variables statistically significant heterogeneity was demonstrated in the standardized incidence rate. High green index was positively associated with the incidence of T1D, as was low population density. For the three remaining socioeconomic variables no clear patterns of associations with incidence of T1D were seen. This study demonstrates a considerable and statistically significant variation between the lowest and highest values in the incidence and prevalence rates for T1D in municipalities of Stockholm County. Such variation seems unlikely to be explained by genetic differences since the population is homogeneous. Our study provides support for the hypothesis that environmental factors have a major influence on the pathogenesis of T1D.

Increasing incidence of type 1 diabetes in children aged 0-14 years in Harbin, China (1990-2000)

AIMS

(1) To determine the incidence of type 1 diabetes mellitus in children aged<15 years in Harbin, China and (2) to examine the trend in incidence over the period from 1990 to 2000.

METHODS

Newly diagnosed cases of type 1 diabetes from 1990 to 2000 were identified among 1,286,154 Chinese children aged 0-14 years in Harbin. The primary source of case ascertainment was from hospital records and the secondary source from the health records of school clinics.

RESULTS

One hundred and three cases were identified during 1990 and 2000. The annual incidence rate was 0.73 per 100,000 (95% CI: 0.59-0.88 per 100,000). No significant difference between males and females in the incidence of type 1 diabetes was observed. The incidence was significantly associated with age. With those aged<5 years as reference, the rate ratios were 2.06 and 4.1 for those aged 5-9 and 10-14 years, respectively. The incidence was higher in urban than in suburban regions, particularly among those aged 10-14 years. No significant seasonality was observed. There was a significant increasing trend in the incidence of type 1 diabetes during the period of 1990 and 2000, with an annual increase of 7.4% (95% CI: 1.6-13.5%).

CONCLUSIONS

There is a significantly increasing trend in the incidence of type 1 diabetes among children in Harbin. Increased number of cases has important implications for diabetes care providers. Understanding the etiology of this rise is critical for developing preventive measures to halt the trend.

Linking stroke mortality with air pollution, income, and greenness in northwest Florida: an ecological geographical study

Background

Relatively few studies have examined the association between air pollution and stroke mortality. Inconsistent and inclusive results from existing studies on air pollution and stroke justify the need to continue to investigate the linkage between stroke and air pollution. No studies have been done to investigate the association between stroke and greenness. The objective of this study was to examine if there is association of stroke with air pollution, income and greenness in northwest Florida.

Results

Our study used an ecological geographical approach and dasymetric mapping technique. We adopted a Bayesian hierarchical model with a convolution prior considering five census tract specific covariates. A 95% credible set which defines an interval having a 0.95 posterior probability of containing the parameter for each covariate was calculated from Markov Chain Monte Carlo simulations. The 95% credible sets are (-0.286, -0.097) for household income, (0.034, 0.144) for traffic air pollution effect, (0.419, 1.495) for emission density of monitored point source polluters, (0.413, 1.522) for simple point density of point source polluters without emission data, and (-0.289,-0.031) for greenness. Household income and greenness show negative effects (the posterior densities primarily cover negative values). Air pollution covariates have positive effects (the 95% credible sets cover positive values).

Conclusion

High risk of stroke mortality was found in areas with low income level, high air pollution level, and low level of exposure to green space.

A low incidence of Type 1 diabetes between 1977 and 2001 in south-eastern Sweden in areas with high population density and which are more deprived

AIMS

To explore how socioeconomic factors and population density may contribute to the geographical variation of incidence of Type 1 diabetes in children in south-eastern Sweden.

METHOD

All children diagnosed with Type 1 diabetes in south-eastern Sweden during 1977-2001 were defined geographically to their place of residence and were allocated x and y coordinates in the national grid. The population at risk and socioeconomic data were aggregated in 82,000 200-m squares and geocoded likewise. A socioeconomic index was calculated using a signed chi(2) method. Rural-urban gradients were defined by overlay analysis in a geographic information system.

RESULTS

The incidence during the past 25 years has been rising steadily, particularly in the last 6 years. The incidence was highest in areas with a high proportion of small families, of families with a high family income and better education, and this was found both at the time of diagnosis and at the time of birth. In the rural-urban analysis, the lowest incidence was found in the urban area with > 20,000 inhabitants, where there was also a higher frequency of deprivation.

CONCLUSIONS

Our findings indicate that geographical variations in incidence rates of Type 1 diabetes in children are associated with socioeconomic factors and population density, although other contributing factors remain to be explained.

Have urban/rural inequalities in suicide in New Zealand grown during the period 1980-2001?

Previous studies have noted that in many countries there has been a disproportionate increase in suicide in rural areas, contributing to greater urban/rural inequalities in health. This paper evaluates whether this trend was also apparent in New Zealand during the 1980s and 1990s, a period of rapid social and economic change. Using suicide incidence data for the period 1980-2001, we investigate whether urban/rural status had an effect upon rates of suicide independently of socioeconomic deprivation. While both male and female suicide rates were significantly higher in urban than rural areas in 1980-1982, by the end of the 1990s, urban/rural differences in suicide rates were not significant. The narrowing of urban/rural differences was, to some extent, a result of the growth in suicide rates in more isolated rural communities and small rural service centres. Recent geographical variations in suicide in New Zealand are therefore to a large extent similar to trends observed elsewhere, but are less marked. Potential explanations are offered for the fluctuating urban/rural inequalities in suicide including compositional arguments, rural restructuring and economic decline, social isolation and health service utilisation.

Secular trends, disease maps and ecological analyses of the incidence of childhood onset Type 1 diabetes in Northern Ireland, 1989-2003

AIMS

To investigate secular trends in the incidence of Type 1 diabetes in Northern Ireland over the period 1989-2003. To highlight geographical variations in the incidence of Type 1 diabetes by producing disease maps and to compare incidence rates by relevant area characteristics.

METHODS

New cases of Type 1 diabetes in children aged 0-14 years in Northern Ireland were prospectively registered from 1989 to 2003. Standardized incidence rates were calculated and secular trends investigated. Bayesian methodology was used to produce maps of disease incidence using small geographical areas (582 electoral wards). Ecological analyses were conducted using Poisson regression to investigate incidence rates by area characteristics at a finer geographical subdivision (5022 census output areas).

RESULTS

In Northern Ireland during 1989-2003, there were 1433 new cases, giving a directly standardized incidence rate of 24.7 per 100,000 person-years. This incidence rate increased by a mean of 4.2% per annum. Disease maps highlighted higher incidence rates in the predominately rural north-east of the province and lower incidence rates in the urban areas around Belfast in the east and Derry in the north-west of the province. Ecological analysis identified higher incidence in rural areas (P < 0.001), areas with low migration rates (P = 0.002), affluent areas (P < 0.0001), sparsely populated areas (P = 0.0001) and remote areas (P = 0.005). CONCLUSIONS In Northern Ireland the incidence of Type 1 diabetes is increasing. The observed higher incidence in rural, affluent, sparsely populated and remote areas may reflect a reduced or delayed exposure to infections in these areas.

‘Help, educate, encourage?’: Geographical variations in the provision and utilisation of diabetes education in New Zealand

In New Zealand, as elsewhere, it is argued that a diabetes epidemic is underway. With careful management from individuals and professionals and appropriate levels of education, it is possible to prevent many complications of diabetes. The overall objective of the paper is to evaluate the role and impact of Diabetes New Zealand (DNZ), the key voluntary sector provider of diabetes education and support services, with respect to four criteria: (i) the extent to which DNZ is reaching groups most at risk of diabetes; (ii) the degree to which it has encouraged levels of member involvement; (iii) whether voluntary group provision of education is that most preferred by members; and (iv) the extent to which members see the voluntary sector model as being effective in combating the growth of diabetes. A survey of members of six of the 41 affiliated societies of DNZ suggests that such organisations, although having a high proportion of older members, have generally failed to target more deprived groups. While the societies generally score more positively in encouraging member involvement and being perceived as effective by their members, they do not always utilise the preferred form of educational provision. However, there are significant contextual variations by urban-rural location and according to the organisational structure of the societies. Rural societies and those with decentralised organisational structures generally score highest on the above criteria. The results pose a problem for DNZ which, like many other voluntary sector organisations, is facing pressures of increased corporatisation and centralisation. We see this as an important challenge that DNZ needs to address if New Zealand is going to better cope with the emerging diabetes epidemic.

Higher incidence of childhood-onset type 1 diabetes mellitus in remote areas: a UK regional small-area analysis

AIMS/HYPOTHESIS

We investigated the association between the incidence of type 1 diabetes mellitus and remoteness (a proxy measure for exposure to infections) using recently developed techniques for statistical analysis of small-area data.

SUBJECTS, MATERIALS AND METHODS

New cases in children aged 0 to 14 years in Northern Ireland were prospectively registered from 1989 to 2003. Ecological analysis was conducted using small geographical units (582 electoral wards) and area characteristics including remoteness, deprivation and child population density. Analysis was conducted using Poisson regression models and Bayesian hierarchical models to allow for spatially correlated risks that were potentially caused by unmeasured explanatory variables.

RESULTS

In Northern Ireland between 1989 and 2003, there were 1,433 new cases of type 1 diabetes, giving a directly standardised incidence rate of 24.7 per 100,000 person-years. Areas in the most remote fifth of all areas had a significantly (p=0.0006) higher incidence of type 1 diabetes mellitus (incidence rate ratio=1.27 [95% CI 1.07, 1.50]) than those in the most accessible fifth of all areas. There was also a higher incidence rate in areas that were less deprived (p<0.0001) and less densely populated (p=0.002). After adjustment for deprivation and additional adjustment for child population density the association between diabetes and remoteness remained significant (p=0.01 and p=0.03, respectively).

CONCLUSIONS/INTERPRETATION

In Northern Ireland, there is evidence that remote areas experience higher rates of type 1 diabetes mellitus. This could reflect a reduced or delayed exposure to infections, particularly early in life, in these areas.

Independent effects of socioeconomic status and place of residence on the incidence of childhood type 1 diabetes in Western Australia

OBJECTIVE

To analyze the incidence of type 1 diabetes in 0- to 14-year olds in Western Australia, from 1985 to 2002, by region and socioeconomic status.

METHODS

Primary case ascertainment was from the prospective population-based Western Australian Diabetes Register, and secondary case ascertainment was from the Western Australian Hospital Morbidity Data System. The address at diagnosis was used to categorize cases into urban, rural and remote areas and into five socioeconomic groups using the Index of Relative Socioeconomic Disadvantage. Denominator data were obtained from the Australian Bureau of Statistics. Poisson regression was used to analyze the incidence rates by area and socioeconomic status.

RESULTS

There were a total of 1143 cases (904 urban, 190 rural and 49 remote). Case ascertainment was estimated to be 99.8% complete. The mean annual age-standardized incidence from 1985 to 2002 was 18.1 per 100,000 person years in urban (95% CI: 16.3-19.9), 14.3 per 100,000 in rural (95% CI: 11.4-7.3) and 8.0 per 100,000 in remote areas (95% CI: 5.8-10.3). The incidence was significantly higher in urban compared with rural (rate ratio 1.27, p = 0.001) and remote (rate ratio 2.28, p < 0.001) areas. The incidence increased with higher socioeconomic status. The incidence in the highest socioeconomic group was 56% greater than the lowest socioeconomic group (rate ratio 1.56, p < 0.001). These differences in incidence by socioeconomic status and region were independent of each other.

CONCLUSIONS

Higher socioeconomic status and residence in the urban area are independently associated with an increased risk of childhood type 1 diabetes in Western Australia.

Exposure to farming environments in early life and type 1 diabetes: a case-control study

It has been hypothesized that a stimulation of regulatory cytokines by microbial compounds reduces autoimmune as well as atopic diseases. Farm-related contact to microbial compounds protects from allergies, but no data on the association between farm contact and type 1 diabetes is available. The aim of this study was to test this association. A case-control study was conducted in five children's hospitals. Regular contact to farm animals and potential confounders were assessed using a postal questionnaire. Eligible subjects were all prevalent cases with type 1 diabetes registered in the hospitals and hospital-based control subjects (response rate 91%). Included were children aged 6-16 years living in rural areas with German nationality (242 case and 224 control subjects). Regular contact to stables (adjusted odds ratio 1.2 [95% CI 0.5-2.7]) was not associated with type 1 diabetes. In addition, regular contact to specific farm animals was not associated with case status. There was a tendency for an inverse relationship between allergic rhinitis and type 1 diabetes (0.6 [0.3-1.1]; P = 0.11). There was no evidence that early exposure to farm animals largely decreases the risk in children for developing type 1 diabetes.

Relationship between the incidence of type 1 diabetes and maternal enterovirus antibodies: time trends and geographical variation

AIMS/HYPOTHESIS

We have previously observed an inverse correlation between the incidence of type 1 diabetes and enterovirus infections in the background population. The aim of this study was to analyse whether maternal enterovirus antibody status, which reflects both the frequency of enterovirus infections and the protection conferred by the mother on the offspring, also correlates with the incidence of type 1 diabetes.

METHODS

Maternal enterovirus antibodies were analysed from serum samples taken from pregnant women between 1983 and 2001 in Finland and Sweden using enzyme immunoassay and neutralisation assays. Comparable samples were also taken between 1999 and 2001 in countries with a lower incidence of diabetes (Estonia, Germany, Hungary, Israel, Lithuania, Russia).

RESULTS

A clear decrease was observed in maternal enterovirus antibody levels over the past 20 years (p<0.0001). The frequency of enterovirus antibodies was higher in countries with a low or intermediate incidence of type 1 diabetes compared with high-incidence countries (p<0.0001).

CONCLUSIONS/INTERPRETATION

These findings are in line with our previous observations supporting the hypothesis that a low frequency of enterovirus infection in the background population increases the susceptibility of young children to the diabetogenic effect of enteroviruses.

Health and GIS: toward spatial statistical analyses

This study examined the extent to which health studies, mostly in public health and epidemiology, used geographical information systems (GIS). We identified a wide range of tools they used-ranging from geocoding through simple buffer/overlay functions to spatial query functions. However, studies tend to rely on tools outside of GIS for spatial statistical analyses. This may reflect a lack of spatial statistical tools that are suitable for health researchers whose data are rather geographically aggregated count data than continuous data. Implementation within GIS of spatial analytical tools suitable for aggregated data over a region will increase the use of GIS beyond simple GIS operations in health studies.