Ecological Regression Research Articles

Years of life lost and mortality due to heat and cold in the three largest English cities

There is a well-established relationship between temperature and mortality, with older individuals being most at risk in high-income settings. This raises the question of the degree to which lives are being shortened by exposure to heat or cold. Years of life lost (YLL) take into account population life expectancy and age at which mortality occurs. However, YLL are rarely used as an outcome-metric in studies of temperature-related mortality. This represents an important gap in knowledge; to better comprehend potential impacts of temperature in the context of climate change and an ageing population, it is important to understand the relationship between temperature and YLL, and also whether the risks of temperature related mortality and YLL have changed over recent years.Gridded temperature data derived from observations, and mortality data were provided by the UK Met Office and the Office for National Statistics (ONS), respectively. We derived YLL for each death using sex-specific yearly life expectancy from ONS English-national lifetables. We undertook an ecological time-series regression analysis, using a distributed-lag double-threshold model, to estimate the relationship between daily mean temperature and daily YLL and mortality between 1996 and 2013 in Greater London, the West Midlands including Birmingham, and Greater Manchester. Temperature-thresholds, as determined by model best fit, were set at the 91st (for heat-effects) and 35th (for cold-effects) percentiles of the mean temperature distribution. Secondly, we analysed whether there had been any changes in heat and cold related risk of YLL and mortality over time.Heat-effects (lag 0–2 days) were greatest in London, where for each 1 °C above the heat-threshold the risk of mortality increased by 3.9% (CI 3.5%, 4.3%) and YLL increased by 3.0% (2.5%, 3.5%). Between 1996 and 2013, the proportion of total deaths and YLL attributable to heat in London were 0.50% and 0.40% respectively. Cold-effects (lag 0–27 days) were greatest in the West Midlands, where for each 1 °C below the cold-threshold, risk of mortality increased by 3.1% (2.4%, 3.7%) and YLL also increased by 3.1% (2.2%, 3.9%). The proportion of deaths and YLL attributable to cold in the West Midlands were 3.3% and 3.2% respectively. We found no evidence of decreasing susceptibility to heat and cold over time.The addition of life expectancy information into calculations of temperature-related risk and mortality burdens for English cities is novel. We demonstrate that although older individuals are at greatest risk of temperature-related mortality, heat and cold still make a significant contribution to the YLL due to premature death.

Triple-negative breast cancer incidence in the United States: ecological correlations with area-level sociodemographics, healthcare, and health behaviors.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, more commonly diagnosed among black women than other subgroups. TNBC varies geographically, but little is known about area-level characteristics associated with elevated incidence. We generated 2011-2013 age-adjusted TNBC incidence rates for state economic areas (SEAs) in 43 states using data from North American Association of Central Cancer Registries. For cases missing data on molecular markers, we imputed TNBC status using cross-marginal proportions. We linked these data to SEA covariates from national sources. Using linear ecological regression, we examined correlates of TNBC incidence rates for the overall population and for age (< 50years or 50 + years)- or race (white or black)-specific subgroups. The mean annual incidence of TNBC across SEAs was 13.7 per 100,000 women (range = 4.5-26.3), with especially high and variable rates among African American women (mean = 20.5, range 0.0-155.1). TNBC incidence was highest in South Atlantic and East South Central Census Divisions and lowest in Mountain Division. Overall TNBC incidence was associated with SEA sociodemographics (e.g., percent of females age 45 + who are non-Hispanic black: coefficient estimate [est.] = 1.62), healthcare characteristics (e.g., percent of population without health insurance: est. = -0.52), and health behaviors (e.g., prevalence of obesity among women: est. = 0.72) (all p < 0.05). Other variables related to TNBC incidence included density of obstetrician/gynecologists and prevalence of smoking. TNBC incidence varied across SEAs in the U.S., particularly for African American women. Identifying areas with elevated TNBC incidence can facilitate research and interventions on area- and individual-level correlates of TNBC.

Projected geographic disparities in healthcare worker absenteeism from COVID-19 school closures and the economic feasibility of child care subsidies: a simulation study

BackgroundSchool closures have been enacted as a measure of mitigation during the ongoing coronavirus disease 2019 (COVID-19) pandemic. It has been shown that school closures could cause absenteeism among healthcare workers with dependent children, but there remains a need for spatially granular analyses of the relationship between school closures and healthcare worker absenteeism to inform local community preparedness.MethodsWe provide national- and county-level simulations of school closures and unmet child care needs across the USA. We develop individual simulations using county-level demographic and occupational data, and model school closure effectiveness with age-structured compartmental models. We perform multivariate quasi-Poisson ecological regressions to find associations between unmet child care needs and COVID-19 vulnerability factors.ResultsAt the national level, we estimate the projected rate of unmet child care needs for healthcare worker households to range from 7.4 to 8.7%, and the effectiveness of school closures as a 7.6% and 8.4% reduction in fewer hospital and intensive care unit (ICU) beds, respectively, at peak demand when varying across initial reproduction number estimates by state. At the county level, we find substantial variations of projected unmet child care needs and school closure effects, 9.5% (interquartile range (IQR) 8.2–10.9%) of healthcare worker households and 5.2% (IQR 4.1–6.5%) and 6.8% (IQR 4.8–8.8%) reduction in fewer hospital and ICU beds, respectively, at peak demand. We find significant positive associations between estimated levels of unmet child care needs and diabetes prevalence, county rurality, and race (p<0.05). We estimate costs of absenteeism and child care and observe from our models that an estimated 76.3 to 96.8% of counties would find it less expensive to provide child care to all healthcare workers with children than to bear the costs of healthcare worker absenteeism during school closures.ConclusionsSchool closures are projected to reduce peak ICU and hospital demand, but could disrupt healthcare systems through absenteeism, especially in counties that are already particularly vulnerable to COVID-19. Child care subsidies could help circumvent the ostensible trade-off between school closures and healthcare worker absenteeism.

A flexible hierarchical framework for improving inference in area-referenced environmental health studies.

Study designs where data have been aggregated by geographical areas are popular in environmental epidemiology. These studies are commonly based on administrative databases and, providing a complete spatial coverage, are particularly appealing to make inference on the entire population. However, the resulting estimates are often biased and difficult to interpret due to unmeasured confounders, which typically are not available from routinely collected data. We propose a framework to improve inference drawn from such studies exploiting information derived from individual-level survey data. The latter are summarized in an area-level scalar score by mimicking at ecological level the well-known propensity score methodology. The literature on propensity score for confounding adjustment is mainly based on individual-level studies and assumes a binary exposure variable. Here, we generalize its use to cope with area-referenced studies characterized by a continuous exposure. Our approach is based upon Bayesian hierarchical structures specified into a two-stage design: (i) geolocated individual-level data from survey samples are up-scaled at ecological level, then the latter are used to estimate a generalized ecological propensity score (EPS) in the in-sample areas; (ii) the generalized EPS is imputed in the out-of-sample areas under different assumptions about the missingness mechanisms, then it is included into the ecological regression, linking the exposure of interest to the health outcome. This delivers area-level risk estimates, which allow a fuller adjustment for confounding than traditional areal studies. The methodology is illustrated by using simulations and a case study investigating the risk of lung cancer mortality associated with nitrogen dioxide in England (UK).

Access to antenatal healthcare and the prevalence of oral clefts: a spatial analysis.

Congenital anomalies are caused by a variety of risk factors, including individual and environmental ones. This study estimated the prevalence of oral clefts and examined their area-level risk indicators using data from The National Congenital Anomaly Survey in South Korea. Disease mapping and ecological regression were used to assess the geographical variation and potential risk indicators for oral clefts, such as living in a rural area, material deprivation, and limited access to antenatal healthcare. In South Korea, 1.15 (95% CI, 1.08-1.23) children out of every 1,000 births were born with oral clefts during 2005 and 2006. The most common oral cleft type was cleft palate, followed by cleft lip, then cleft lip and palate. Disease mapping showed that the proportion of areas with a higher risk than the national average was relatively higher for oral clefts than for all congenital abnormalities among rural and healthcare underserved areas. The relative risk of oral cleft prevalence was higher in rural areas and healthcare underserved areas than in urban areas and areas with better access to healthcare. The findings suggest that access to antenatal healthcare as well as area-level risk indicators should be considered a priority when developing measures to decrease the occurrence of oral clefts.

Hip fractures and characteristics of living area: a fine-scale spatial analysis in France.

Several studies have shown great disparities in spatial repartition of hip fractures (HF). The aim of the study was to analyze the association between HF incidence and characteristics of the living area. All patients aged 50 or older, living in France, who were hospitalized for HF between 2012 and 2014 were included, using the French national hospital discharge database. Standardized incidence ratio (SIR) was calculated for each spatial unit and adjusted on age and sex. An ecological regression was performed to analyze the association between HF standardized incidence and ecological variables. We adjusted the model for neighborhood spatial structure. We used three variables to characterize the living areas: a deprivation index (French-EDI); healthcare access (French standardized index); land use (percentage of artificialized surfaces). A total of 236,328 HF were recorded in the French hospital national database, leading to an annual HF incidence of 333/100,000. The spatial analysis revealed geographical variations of HF incidence with SIR varying from 0.67 (0.52; 0.85) to 1.45 (1.23; 1.70). There was a significant association between HF incidence rates and (1) French-EDI (trend p = 0.0023); (2) general practitioner and nurse accessibility (trend p = 0.0232 and p = 0.0129, respectively); (3) percentage of artificialized surfaces (p < 0.0001). The characteristics of the living area are associated with significant differences in the risk of hip fracture of older people.

Childhood type 1 diabetes: an environment-wide association study across England

Aims/hypothesisType 1 diabetes is an autoimmune disease affecting ~400,000 people across the UK. It is likely that environmental factors trigger the disease process in genetically susceptible individuals. We assessed the associations between a wide range of environmental factors and childhood type 1 diabetes incidence in England, using an agnostic, ecological environment-wide association study (EnWAS) approach, to generate hypotheses about environmental triggers.MethodsWe undertook analyses at the local authority district (LAD) level using a national hospital episode statistics-based incident type 1 diabetes dataset comprising 13,948 individuals with diabetes aged 0–9 years over the period April 2000 to March 2011. We compiled LAD level estimates for a range of potential demographic and environmental risk factors including meteorological, land use and environmental pollution variables. The associations between type 1 diabetes incidence and risk factors were assessed via Poisson regression, disease mapping and ecological regression.ResultsCase counts by LAD varied from 1 to 236 (median 33, interquartile range 24–46). Overall type 1 diabetes incidence was 21.2 (95% CI 20.9, 21.6) per 100,000 individuals. The EnWAS and disease mapping indicated that 15 out of 53 demographic and environmental risk factors were significantly associated with diabetes incidence, after adjusting for multiple testing. These included air pollutants (particulate matter, nitrogen dioxide, nitrogen oxides, carbon monoxide; all inversely associated), as well as lead in soil, radon, outdoor light at night, overcrowding, population density and ethnicity. Disease mapping revealed spatial heterogeneity in type 1 diabetes risk. The ecological regression found an association between type 1 diabetes and the living environment domain of the Index of Multiple Deprivation (RR 0.995; 95% credible interval [CrI] 0.991, 0.998) and radon potential class (RR 1.044; 95% CrI 1.015, 1.074).Conclusions/interpretationOur analysis identifies a range of demographic and environmental factors associated with type 1 diabetes in children in England.

Effect of the recent economic crisis on socioeconomic inequalities in mortality in nine urban areas in Europe

ObjectiveTo analyse socioeconomic inequalities in all-cause mortality among men and women in nine European urban areas during the recent economic crisis, and to compare the results to those from two periods before the crisis. MethodThis is an ecological study of trends based on three time periods (2000-2003, 2004-2008 and 2009-2014). The units of analysis were the small areas of nine European urban areas. We used a composite deprivation index as a socioeconomic indicator, along with other single indicators. As a mortality indicator, we used the smoothed standardized mortality ratio, calculated using the hierarchical Bayesian model proposed by Besag, York and Mollié. To analyse the evolution of socioeconomic inequalities, we fitted an ecological regression model that included the socioeconomic indicator, the period of time, and the interaction between these terms. ResultsWe observed significant inequalities in mortality among men for almost all the socioeconomic indicators, periods, and urban areas studied. However, no significant changes occurred during the period of the economic crisis. While inequalities among women were less common, there was a statistically significant increase in inequality during the crisis period in terms of unemployment and the deprivation index in Prague and Stockholm, respectively. ConclusionsFuture analyses should also consider time-lag in the effect of crises on mortality and specific causes of death, and differential effects between genders.

Dietary Intakes As Potential Risk Factors for COVID-19 Mortality: A Multicountry Ecological Bayesian Regression Analysis

Background: Case-fatality rate (CFR) of the COVID-19 pandemic varied from one country to another We aimed to describe the association between the global mortal

Analysis of road mortality in digital age using Bayesian ecological model: the case of Tunisia

While awareness of the public health burden of road insecurity is recent, the idea that it is developing countries, particularly in Africa, that experience high road deaths is older. Tunisia is an example of this. In this context, our article proposes recommendations through the study of the road mortality rate in Tunisia based on population density and belonging to a geographical unit. To do so, we used the Bayesian ecological regression model whose parameters are adjusted by Gibbs sampling. The analysis shows that the variation in road mortality risk is highest at the delegation level but lowest at the district and governorate levels. An estimated elasticity of −0.25 at the district level means that a 10% increase in population density can lead to a 2.5% decrease in road deaths. Bayes Relative Risk Mapping could help identify areas with high road mortality and strengthen road safety decision making.

Bayesian smoothed small-areas analysis of urban inequalities in fertility across 1999\u20132013

BackgroundSince the 2008 economic crisis in Spain, overall fertility has continued to decrease, while urban inequalities have increased. There is a general lack of studies of fertility patterns in small-areas of Spanish cities. We explored the effects of the economic crisis on fertility during three time periods in urban settings in Spain.MethodsWe studied the distribution of fertility rates among women (15–49 years) from Spain and low-middle income countries (LIC) who were living in 13 Spanish cities. We mapped fertility and the MEDEA socioeconomic deprivation index in small-areas, and analyzed age-related trends in fertility rates. We performed an ecological regression analysis of fertility and the deprivation index in two pre-crisis periods (1999–2003 and 2004–2008) and one crisis period (2009–2013). Fertility rates were calculated and smoothed using the hierarchical Bayesian model (BYM).ResultsHigher fertility was generally associated with socioeconomic deprivation, with adjustment for the mothers’ age and nationality. While Spanish citizens tended to delay childbearing throughout the three study periods, fertility increased among Spanish adolescents from deprived urban areas during the economic crisis. There was a general decline in fertility among immigrants after the crisis, especially in southern cities. Overall, fertility appeared to be stable, with higher fertility in more deprived areas.ConclusionIncreased unemployment and changes to government family policies may have contributed to delayed childbearing in Spain. For immigrants, more restrictive immigration policies may have played a crucial role in decreasing fertility rates. Reforming such policies will be key for better reproductive rights and improved fertility rates across all population cohorts in Spain.

Use and expenditures on public access hunting lands

The recreational and economic benefits of hunting on traditional permanent public lands are well-established. Increasingly popular “open fields” hunting access programs temporarily open private lands to public hunting through public-private partnerships. Open fields programs have the potential to create public hunting opportunities and economic development in rural communities, but the extent to which open fields programs compare to traditional public lands at providing benefits to hunters and rural communities has not yet been evaluated. We compared hunter use and expenditures on open fields lands and traditional public lands in Nebraska, USA. We used Convolution Likelihood Ecological Abundance Regression, a novel Bayesian abundance estimation method, to predict hunter effort, target species, and total expenditures using combined inferences from hunter count surveys, camera traps, and extensive in-person interviews. Open fields sites generally provided lower hunter use and expenditure returns per unit area than did traditional public lands. However, open fields and traditional public lands provided similar returns in one study region prioritized for highly-publicized upland gamebird opportunities. Our findings demonstrate that open fields programs can create returns in use and hunter expenditures when paired with strategic communication initiatives and further suggest that access programs may benefit from enrolling properties that provide diverse opportunities. Management implicationThe study shows, that public access hunting lands near urban areas receive relatively high use, but hunter expenditures may be greater in ecological rich rural areas. Public-private hunting access partnerships can create returns in hunter use and expenditures when they provide access to valued, highly-publicized hunting opportunities.

Different transmission routes and the risk of advanced HIV disease: A systematic review and network meta-analysis of observational studies

BackgroundA substantial proportion of people living with HIV (PLHIV) present for care with advanced HIV disease (AHD), which may result in difficulty reaching the “90–90–90” target to end AIDS in 2030. We assessed the risk of AHD for different transmission routes to summarize the evidence for priority prevention strategies for key populations. MethodsObservational studies published before September 10th, 2019 in the PubMed, EMBASE, Web of Science and Chinese electronic databases were analysed. The outcomes of interest were the number of PLHIV and AHD patients and their associated transmission routes. We assessed the risk of AHD among the different transmission routes using the multi-armed network meta-analysis based on the Bayesian method. The associations between AHD and regional policies for sex work and compulsory drug treatment were estimated using ecological linear regression. FindingsOne hundred and one articles were included, covering 1,297,872 PLHIV with 478,830 patients who developed AHD. The network analysis revealed that among PLHIV, heterosexual contact was associated with the highest risk of AHD, followed by injection drug use (odds ratio [OR]=0•56, 95% credible interval [CrI] 0•47–0•68), and men who have sex with men (OR=0•54, 95% CrI 0•46–0•63). Regions that criminalized sex work and compulsory drug treatment had higher risks for AHD than those that did not. InterpretationOur findings suggest HC is at a higher risk of AHD compared to IDU and MSM. This justifies the need to expand prevention campaigns and maintain efforts to increase HIV testing in the heterosexual population.

Citizens\u2019 initiatives for care and welfare in the Netherlands: an ecological analysis

BackgroundIn the Netherlands as well as in other countries citizens take initiatives to provide or maintain services in the area of care and welfare. Citizens’ initiatives (CI’s) are organisations some of which have a formal structure while others are informally connected groups of citizens, that are established by a group of citizens with the aim to increase the health and welfare within their local community and that are not focused on making a profit. Although CI’s have been around since at least the 1970’s little research has been done on the phenomenon, with most of it consisting of case studies or qualitative exploratory research. To fill part of this gap in knowledge, we have studied the geographical variation in the presence of CI’s in the Netherlands and tried to explain this variation.MethodsData on the presence of CI’s were obtained by combining two existing inventories. We did an ecological regression analysis to test hypotheses about the relationship between the presence of CI’s and the existence of a care vacuum, the capacity for self-organisation and models of action in local communities.ResultsWe counted 452 CI’s in care and welfare in the Netherlands in January 2016. Our results show a spatial concentration of care initiatives in urban areas in the Randstad cities in the west of the country and in rural areas in the south-east. The presence of CI’s is only weakly associated with a care vacuum, but is related to indicators for the capacity of concerted action and models of action.ConclusionThere are by now a considerable number of CI’s in the area of care and welfare in the Netherlands. Apparently, citizens take collective initiatives to provide services that are not, or no longer, available to the local community. The initiatives are concentrated in certain parts of the country. However, our theoretical model to explain this geographical pattern is only partially confirmed.

Fine-scale geographical distribution and ecological risk factors for Crohn's disease in France (2007-2014).

Geographical variations in Crohn's disease (CD) suggest that the environment has a role in the pathogenesis of this condition. To describe the spatial distribution and the clustering of CD cases in France, and to assess the relationship between the prevalence of CD and environmental risk factors. We identified all patients with CD included in the French hospital discharge database from 2007 to 2014. Age- and gender-smoothed standardised prevalence ratios over this period were computed for 5610 spatial units. An ecological regression analysis was used to assess the relationship between the risk of CD and ecological variables (health care, latitude, socio-economic deprivation, urbanisation, proportion of agricultural surfaces and density of industries). Local spatial clusters of high-CD prevalence were searched for using elliptic spatial scan statistics and characterised in a hierarchical ascendant classification based on the same ecological variables. About 129089 patients with CD were identified, yielding a crude prevalence of 203 per 100000 inhabitants. The overall spatial heterogeneity was statistically significant (P<.001). An elevated risk of CD was found to be significantly associated with high-social deprivation (relative risk [95% confidence interval]=1.05 [1.02-1.08]) and high urbanisation (1.09 [1.04-1.14]). Sixteen significant spatial clusters of high-CD prevalence were identified; there were no common ecological variables. The geographical distribution of CD prevalence in France is not uniform, and is associated with high levels of social deprivation and urbanisation. Larger ecological databases integrating more detailed environmental and clinical information are needed.

Childhood Type 1 Diabetes

PDS 71: Exposome, Johan Friso Foyer, Floor 1, August 27, 2019, 4:30 PM - 5:30 PM Background/Aim: Type 1 Diabetes (T1D) is an autoimmune disease affecting ~400,000 people across the UK. Environmental factors likely trigger the disease process in genetically susceptible individuals. We assessed the associations between a wide range of environmental factors and childhood T1D incidence in England, using an agnostic, ecological Environment Wide Association Study (EWAS) approach, to generate hypotheses about environmental triggers. Methods: We undertook analyses at the Local Authority District (LAD) level using a national Hospital Episode Statistics (HES) based incident T1D dataset, comprising 13,948 cases aged 0-9 years over the period April 2000- March 2011. We compiled LAD-level estimates for a range of potential demographic and environmental risk factors including meteorological, land use and environmental pollution variables. The associations between T1D incidence and risk factors were assessed via Poisson regression, disease mapping and ecological regression. Results: Case counts by LAD varied from 1 to 236 (median 33; inter quartile range: 24-46). Overall T1D incidence was 21.2 (95% CI 20.9-21.6) per 100,000 individuals. The EWAS and disease mapping indicated that 15 out of 53 demographic and environmental risk factors were significantly associated with diabetes incidence after adjusting for multiple testing. These included air pollutants (particulate matter, nitrogen dioxide, nitrogen oxides, carbon monoxide), as well as lead in soil, radon, outdoor light at night, overcrowding, population density and ethnicity. Disease mapping revealed spatial heterogeneity in T1D risk. The ecological regression found a significant association between T1D and the living environment domain of the Index of Multiple Deprivation (RR 0.995 (95%CI 0.991-0.998)) and radon potential class (RR 1.044 95%CI 1.015-1.074). Conclusions: Our analysis identifies a range of demographic and environmental factors associated with T1D in children in England.

Estimating the Use of Public Lands: Integrated Modeling of Open Populations with Convolution Likelihood Ecological Abundance Regression

We present an integrated open population model where the population dynamics are defined by a differential equation, and the related statistical model utilizes a Poisson binomial convolution likelihood. Key advantages of the proposed approach over existing open population models include the flexibility to predict related, but unobserved quantities such as total immigration or emigration over a specified time period, and more computationally efficient posterior simulation by elimination of the need to explicitly simulate latent immigration and emigration. The viability of the proposed method is shown in an in-depth analysis of outdoor recreation participation on public lands, where the surveyed populations changed rapidly and demographic population closure cannot be assumed even within a single day.

Assessing the Effects on Health Inequalities of Differential Exposure and Differential Susceptibility of Air Pollution and Environmental Noise in Barcelona, 2007-2014.

The hypotheses we intended to contrast were, first, that the most deprived neighborhoods in Barcelona, Spain, present high exposure to environmental hazards (differential exposure) and, secondly, that the health effects of this greater exposure were higher in the most deprived neighborhoods (differential susceptibility). The population studied corresponded to the individuals residing in the neighborhoods of Barcelona in the period 2007–2014. We specified the association between the relative risk of death and environmental hazards and socioeconomic indicators by means of spatio-temporal ecological regressions, formulated as a generalized linear mixed model with Poisson responses. There was a differential exposure (higher in more deprived neighborhoods) in almost all the air pollutants considered, when taken individually. The exposure was higher in the most affluent in the cases of environmental noise. Nevertheless, for both men and women, the risk of dying due to environmental hazards in a very affluent neighborhood is about 30% lower than in a very depressed neighborhood. The effect of environmental hazards was more harmful to the residents of Barcelona’s most deprived neighborhoods. This increased susceptibility cannot be attributed to a single problem but rather to a set of environmental hazards that, overall, a neighborhood may present.

Ecological Regression with Partial Identification

Ecological inference (EI) is the process of learning about individual behavior from aggregate data. We relax assumptions by allowing for “linear contextual effects,” which previous works have regarded as plausible but avoided due to nonidentification, a problem we sidestep by deriving bounds instead of point estimates. In this way, we offer a conceptual framework to improve on the Duncan–Davis bound, derived more than 65 years ago. To study the effectiveness of our approach, we collect and analyze 8,430 $2\times 2$ EI datasets with known ground truth from several sources—thus bringing considerably more data to bear on the problem than the existing dozen or so datasets available in the literature for evaluating EI estimators. For the 88% of real data sets in our collection that fit a proposed rule, our approach reduces the width of the Duncan–Davis bound, on average, by about 44%, while still capturing the true district-level parameter about 99% of the time. The remaining 12% revert to the Duncan–Davis bound.

Research on the Ecological Regression to Chinese Korean Traditional Sports Culture

Nowadays, Chinese traditional sports culture is facing the strong impact of western modern sports culture. Nevertheless it presents three features: rich diversity, prominent scientificity, and distinct affinity to the people, which produce enough inner strength to recover and restore the ecological balance through self-adjustment. This paper takes Chinese Korean traditional sports culture as the research object to construct a theoretical framework of protecting and inheriting Chinese Korean traditional sports culture according to the construction logic of “society-economy-nature” complex ecosystem. Through interaction with external natural, economic and social environment, it should be possible to realize the true meaning of “ecological regression” for Chinese Korean traditional sports culture. We propose three ecological regression paths to Chinese Korean traditional sports culture as follows. Firstly, the integration of natural ecology and economic development shapes the economic form of sustainable development. Secondly, People, academia and authority, the tripartite coalition should enjoy the traditional national sports culture positively, that is to create favorable conditions to make full use of the traditional national sports culture heritage. Thirdly, the government should look for ways to return to the ecological nature through integrating into the management thought of “governing by doing nothing”. This paper presents not only a new perspective for the research of Chinese Korean national sports culture, but also a theoretical way to integrate sports culture with national culture. Furthermore, the research on the inheritance and development of Chinese Korean traditional sports culture will have important academic value and practical learn for the inheritance and development of Korean traditional culture including countries on the Korean peninsula.