Mortality among residents near cokeworks in Great Britain

Association between neighborhood disadvantage and fulfillment of desired postpartum sterilization

BACKGROUND

Adequacy of prenatal care is associated with fulfillment of postpartum sterilization requests, though it is unclear whether this relationship is indicative of broader social and structural determinants of health or reflects the mandatory Medicaid waiting period required before sterilization can occur. We evaluated the relationship between neighborhood disadvantage (operationalized by the Area Deprivation Index; ADI) and the likelihood of undergoing postpartum sterilization.

METHODS

Secondary analysis of a single-center retrospective cohort study examining 8654 postpartum patients from 2012 to 2014, of whom 1332 (15.4%) desired postpartum sterilization (as abstracted from the medical record at time of delivery hospitalization discharge) and for whom ADI could be calculated via geocoding their home address. We determined the association between ADI and sterilization completion, postpartum visit attendance, and subsequent pregnancy within 365 days of delivery via logistic regression and time to sterilization via Cox proportional hazards regression.

RESULTS

Of the 1332 patients included in the analysis, patients living in more disadvantaged neighborhoods were more likely to be younger, more parous, delivered vaginally, Black, unmarried, not college educated, and insured via Medicaid. Compared to patients living in less disadvantaged areas, patients living in more disadvantaged areas were less likely to obtain sterilization (44.8% vs. 53.5%, OR 0.84, 95% CI 0.75-0.93), experienced greater delays in the time to sterilization (HR 1.23, 95% CI 1.06-1.44), were less likely to attend postpartum care (58.9% vs 68.9%, OR 0.86, CI 0.79-0.93), and were more likely to have a subsequent pregnancy within a year of delivery (15.1% vs 10.4%, OR 1.56, 95% CI 1.10-1.94). In insurance-stratified analysis, for patients with Medicaid, but not private insurance, as neighborhood disadvantage increased, the rate of postpartum sterilization decreased. The rate of subsequent pregnancy was positively associated with neighborhood disadvantage for both Medicaid as well as privately insured patients.

CONCLUSION

Living in an area with increased neighborhood disadvantage is associated with worse outcomes in terms of desired postpartum sterilization, especially for patients with Medicaid insurance. While revising the Medicaid sterilization policy is important, addressing social determinants of health may also play a powerful role in reducing inequities in fulfillment of postpartum sterilization.

Fractionation of trace elements and human health risk of submicron particulate matter (PM1) collected in the surroundings of coking plants

Samples of PM1 were collected in the surroundings of coking plants located in southern Poland. Chemical fractionation provided information on the contents of trace elements As, Cd, Co, Cr, Hg, Mn, Ni, Pb, Sb and Se in all mobile (F1-F3) and not mobile (F4) fractions of PM1 in the vicinity of large sources of emissions related to energochemical processing of coal during the summer. The determined enrichment factors indicate the influence of anthropogenic sources on the concentration of the examined elements contained in PM1 in the areas subjected to investigation. The analysis of health risk for the assumed scenario of inhabitant exposure to the toxic effect of elements, based on the values of the hazard index, revealed that the absorption of the examined elements contained in the most mobile fractions of particulate matter via inhalation by children and adults can be considered potentially harmless to the health of people inhabiting the surroundings of coking plants during the summer (HI < 1). It has been estimated that due to the inhalation exposure to carcinogenic elements, i.e., As, Cd, Co, Cr, Ni and Pb, contained in the most mobile fractions (F1 + F2) of PM1, approximately four adults and one child out of one million people living in the vicinity of the coking plants may develop cancer.

Impact of large industrial emission sources on mortality and morbidity in Chile: A small-areas study

Chile suffers significant pollution from large industrial emitters associated with the mining, metal processing, paper production, and energy industries. The aim of this research was to determine whether the presence of large industrial facilities (i.e. coal- and oil-fired power plants, pulp and paper mills, mining facilities, and smelters) affects mortality and morbidity rates in Chile. For this, we conducted an ecological study that used Chilean communes as small-area observation units to assess mortality and morbidity. Public databases provided information on large pollution sources relevant to Chile. The large sources studied were oil- and coal-fired power plants, copper smelters, pulp and paper mills, and large mining facilities. Large sources were filtered by first year of production, type of process, and size. Mortality and morbidity data were acquired from public national databases, with morbidity being estimated from hospitalization records. Cause-specific rates were calculated for the main outcomes: cardiovascular, respiratory, cancer; and other more specific health outcomes. The impact of the large pollution sources was estimated using Bayesian models that included spatial correlation, overdispersion, and other covariates. Large and significant increases in health risks (around 20%-100%) were found for communes with power plants and smelters for total, cardiovascular, respiratory, all-cancer, and lung cancer mortality. Higher hospitalization rates for cardiovascular disease, respiratory disease, cancer, and pneumonia (20-100%) were also found for communes with power plants and smelters. The impacts were larger for men than women in terms of both mortality and hospitalizations. The impacts were also larger when the sources were analyzed as continuous (production volume) rather than dichotomous (presence/absence) variables. In conclusion, significantly higher rates of total cardiovascular, respiratory, all-cancer and lung cancer mortality and cardiovascular, respiratory, cancer and pneumonia hospitalizations were observed in communes with power plants and smelters.

Exposure to occupational air pollution and cardiac function in workers of the Esfahan Steel Industry, Iran

Air pollution is recognized as an important risk factor for cardiovascular disease. We investigated association of exposure to occupational air pollution and cardiac function in the workers of the steel industry. Fifty male workers of the agglomeration and coke-making parts of the Esfahan Steel Company were randomly selected (n = 50). Workers in the administrative parts were studied as controls (n = 50). Those with known history of hypertension, dyslipidemia, or diabetes, and active smokers were not included. Data of age, body mass index, employment duration, blood pressure, fasting blood sugar, and lipid profile were gathered. Echocardiography was performed to evaluate cardiac function. Left ventricular ejection fraction was lower in workers of the agglomeration/coke-making parts than in controls (mean difference = 5 to 5.5 %, P < 0.001). Mild right ventricular dilatation and grade I pulmonary hypertension were present in three (12 %) workers of the coke-making part, but none of the controls (P = 0.010). According to these results, occupational air pollution exposure in workers of the steel industry is associated with left heart systolic dysfunction. Possible right heart insults due to air pollution exposure warrant further investigations.

Lung cancer risk and past exposure to emissions from a large steel plant

We studied the spatial distribution of cancer incidence rates around a large steel plant and its association with historical exposure. The study population was close to 600,000. The incidence data was collected for 1995–2006. From historical emission data the air pollution concentrations for polycyclic aromatic hydrocarbons (PAH) and metals were modelled. Data were analyzed using Bayesian hierarchical Poisson regression models. The standardized incidence ratio (SIR) for lung cancer was up to 40% higher than average in postcodes located in two municipalities adjacent to the industrial area. Increased incidence rates could partly be explained by differences in socioeconomic status (SES). In the highest exposure category (approximately 45,000 inhabitants) a statistically significant increased relative risk (RR) of 1.21 (1.01–1.43) was found after adjustment for SES. The elevated RRs were similar for men and women. Additional analyses in a subsample of the population with personal smoking data from a recent survey suggested that the observed association between lung cancer and plant emission, after adjustment for SES, could still be caused by residual confounding. Therefore, we cannot indisputably conclude that past emissions from the steel plant have contributed to the increased risk of lung cancer.

A review of the epidemiological methods used to investigate the health impacts of air pollution around major industrial areas

We performed a literature review to investigate how epidemiological studies have been used to assess the health consequences of living in the vicinity of industries. 77 papers on the chronic effects of air pollution around major industrial areas were reviewed. Major health themes were cancers (27 studies), morbidity (25 studies), mortality (7 studies), and birth outcome (7 studies). Only 3 studies investigated mental health. While studies were available from many different countries, a majority of papers came from the United Kingdom, Italy, and Spain. Several studies were motivated by concerns from the population or by previous observations of an overincidence of cases. Geographical ecological designs were largely used for studying cancer and mortality, including statistical designs to quantify a relationship between health indicators and exposure. Morbidity was frequently investigated through cross-sectional surveys on the respiratory health of children. Few multicenter studies were performed. In a majority of papers, exposed areas were defined based on the distance to the industry and were located from <2 km to >20 km from the plants. Improving the exposure assessment would be an asset to future studies. Criteria to include industries in multicenter studies should be defined.

Case-crossover analysis of air pollution and cardiorespiratory hospitalizations: using routinely collected health and environmental data for tracking: science and data

BACKGROUND

From the early 1900s until its closure in February 1998, a Steel coke oven in Pittsburgh, Pennsylvania, was a key source of air pollution. A case-crossover study was performed to assess the associations between daily air pollution and cardiorespiratory (International Classification of Disease Ninth Revision [ICD-9]: 390-519) hospitalizations before and after plant closure and to evaluate how closure influenced these associations.

METHODS

Air pollution data, climatic data, and cardiorespiratory hospitalizations among residents ages 65 years and older were obtained for the period of 1996 through 2000 for the study area. Data were analyzed using a case-crossover design and conditional logistical regression. Two distinct referent-sampling approaches were compared.

RESULTS

Significant associations were observed between the fourth quartile in PM10 and cardiorespiratory hospitalizations (odds ratio [OR]: 1.12; 95% CI: 1.02-1.23) and cardiovascular hospitalizations only (ICD-9: 390-459) (OR: 1.13; 95% CI: 1.01-1.26) before the plant closure. After closure of the plant, PM10 was not significantly associated with cardiorespiratory or cardiovascular disease hospitalizations. Moreover, the referent sampling approaches did not greatly alter the estimations in the case-crossover analysis.

CONCLUSIONS

Existing secondary data are an economical source to assess the impact of point source pollution on the environmental landscape. The findings suggest that closure of the steel coke plant was associated with a reduction risk of the cardiovascular hospitalizations.

Geographic-based ecological correlation studies using supplemental case-control data

It is well known that the ecological study design suffers from a variety of biases that render the interpretation of its results difficult. Despite its limitations, however, the ecological study design is still widely used in a range of disciplines. The only solution to the ecological inference problem is to supplement the aggregate data with individual-level data and, to this end, Haneuse and Wakefield (Biometrics 2007; 63:128-136) recently proposed a hybrid study design in which an ecological study is supplemented with a sample of case-control data. The latter provides the basis for the control of bias, while the former may provide efficiency gains. Building on that work, we illustrate the use of the hybrid design in the context of a geographical correlation study of lung cancer mortality from the state of Ohio. Focusing on epidemiological applications, we initially provide an overview of the use of ecological studies in scientific research, highlighting the breadth of current application as well as advantages and drawbacks of the design. We consider the interplay between the two sources of information in the design: ecological and case-control, and then provide details on a Bayesian spatial random effects model in the setting of the hybrid design. Issues of specification are addressed, as well as sensitivity to modeling assumptions. Further, an interesting feature of these data is that they provide an example of how the proposed design may be used to resolve the ecological fallacy.

A test of association between spatially defined exposure patterns and health outcome risk contours

Advances in the availability of geographically referenced health and environmental quality data of high spatial resolution have created new opportunities in environmental epidemiology. Novel statistical methods for linking health, exposure, and hazards are required to underpin the development of public health tracking. A test for the association between spatial contours of health risk and exposure is outlined. This test is examined using, as an example, the spatial contours of congenital malformation risk obtained from a routine dataset in the vicinity of a landfill site and an exposure model based on exponential reduction with distance from the site. Spatial contours of risk of congenital malformation were simulated using the exposure model stated and a given population pattern. These were compared with the corresponding expected risk derived from routine birth data to yield relative risk contours. For each simulation three test statistics were devised: the slope of the regression line of standardized relative risk on exposure level, the proportion of standardized relative risks above zero, and the mean standardized relative risk of individuals not subject to exposure. The distributions of these test statistics (under the null no exposure from site and alternative hypotheses) were determined from a simulation exercise. A comparison of receiver operator characteristic (ROC) curves between those relating to the proposed test and those relating to a widely used method proposed by Stone (1988) demonstrated our test to be more efficient. Formal statistical testing of the concordance between spatial contours of risk and environmental exposure enables optimal use of spatial data.

New developments in exposure assessment: the impact on the practice of health risk assessment and epidemiological studies

The field of exposure assessment has matured significantly over the past 10-15 years. Dozens of studies have measured the concentrations of numerous chemicals in many media to which humans are exposed. Others have catalogued the various exposure pathways and identified typical values which can be used in the exposure calculations for the general population such as amount of water or soil ingested per day or the percent of a chemical than can pass through the skin. In addition, studies of the duration of exposure for many tasks (e.g. showering, jogging, working in the office) have been conducted which allow for more general descriptions of the likely range of exposures. All of this information, as well as the development of new and better models (e.g. air dispersion or groundwater models), allow for better estimates of exposure. In addition to identifying better exposure factors, and better mathematical models for predicting the aerial distribution of chemicals, the conduct of simulation studies and dose-reconstruction studies can offer extraordinary opportunities for filling in data gaps regarding historical exposures which are critical to improving the power of epidemiology studies. The use of probabilistic techniques such as Monte Carlo analysis and Bayesian statistics have revolutionized the practice of exposure assessment and has greatly enhanced the quality of the risk characterization. Lastly, the field of epidemiology is about to undergo a sea change with respect to the exposure component because each year better environmental and exposure models, statistical techniques and new biological monitoring techniques are being introduced. This paper reviews these techniques and discusses where additional research is likely to pay a significant dividend. Exposure assessment techniques are now available which can significantly improve the quality of epidemiology and health risk assessment studies and vastly improve their usefulness. As more quantitative exposure components can now be incorporated into these studies, they can be better used to identify safe levels of exposure using customary risk assessment methodologies. Examples are drawn from both environmental and occupational studies illustrating how these techniques have been used to better understand exposure to specific chemicals. Some thoughts are also presented on what lessons have been learned about conducting exposure assessment for health risk assessments and epidemiological studies.

Lung cancer in an urban area in Northern Italy near a coke oven plant

Coke ovens are well-known sources of potentially carcinogenic air pollutants, but studies on resident populations are still poor. This study investigates the incidence of lung cancer near a coke oven in Cornigliano, a district of the Genoa municipality in Northern Italy. Genoa proper and one district similar to Cornigliano as regards socio-economic deprivation were selected as referents. Incidence data were drawn from the Ligurian Cancer Registry for 1986-1997 calendar period. Concentrations of pollutants related to the industrial activity (namely benzene, benzo[a]pyrene, PM(10), CO, NO(2) and SO(2)) were collected in selected locations before and after the coke oven closing. Spatial trend around the plant was assessed by Stone's test, while the pattern of risk across Cornigliano was evaluated via disease mapping in a Bayesian model. A gradient of air pollutants was observed around the coke oven, which disappeared after its closing. In Cornigliano, 158 lung cancer cases were observed in males and 28 in females. Only a marginal excess risk was observed versus the two selected referents, while a gradient in the areas close to the plant emerged among females. Disease mapping revealed another cluster of risk for both sexes in the Eastern part of the district, where a foundry was operative until the early 1980s. The excess risk for females is consistent with pollution measurements and with other epidemiological evidence. The geographic pattern of incidence suggests a role of industrial air pollution as a risk factor for lung cancer.

Exposure to ambient air pollution and prenatal and early childhood health effects

Over the last years, concern for the possible influence of exposure to air pollutants in children during gestation or the first years of life has grown; exposure levels which may be reached nowadays in our dwellings and in our streets. In the present study evidence over the possible impact of ambient air pollution on the foetus and the infants (i.e.: less than 1 year) published during the last decade, 1994--2003, are revised. Studies on infant mortality and exposure to particles show an outstanding consistence in the magnitude of the effects, despite the different designs used. As a whole, data show that an increase in 10 microg/m3 of particle concentration (measured as PM10) is associated with to about 5% increase in post-neonatal mortality for all causes and around 22% for post-neonatal mortality for respiratory diseases. Regarding damage in foetal health, although results are not always consistent, most studies show associations with exposure to air pollution during pregnancy. However, the precise mechanisms of action of air pollutants on adverse reproductive results are still unknown, so is the period of exposure most relevant during pregnancy and the specific pollutant which may represent a higher risk. Follow-up studies evaluating personal exposure to different air pollutants are required, allowing for the adequate evaluation of the impact of each pollutant in different periods of pregnancy, as well as providing hypotheses on their possible mechanisms of action.

Controlling for provider of treatment in the modelling of respiratory disease risk near cokeworks

The improved quality of hospital admissions data makes them a valuable resource for researchers. However, we show that, when multiple providers of health care are considered, the provider (in this case hospital) may act like other confounders such as socio-economic status, and hence must be controlled for. Such control is not as straightforward as for conventional confounders, however, but we describe a method that is appropriate under certain assumptions. We also describe a number of other statistical issues, such as the modelling of spatial and non-spatial overdispersion, that arose during the use of hospital data in a study to investigate the possible adverse health effects of living in proximity to six cokeworks groups in England and Wales. The outcome data that we consider consist of hospital admissions for all respiratory disease in the under-5s. The ecological level of the analysis is the census-defined enumeration district, and the main (proxy) exposure measure utilised is the spatial location of the enumeration district population-weighted centroid in relation to the cokeworks. We focus on the Teesside cokeworks group, for which we also had sulphur dioxide measurements from dispersion modelling as an alternative exposure measure. The major local providers varied appreciably in their standardized admission ratios for respiratory disease, and when provider was controlled for, the size of the observed excess risk found close to the cokeworks was decreased, making control for the provider of health care vital. However, the presence of multiple pollution sources, in addition to the usual shortcomings of ecological studies, makes interpretation difficult.

Proximity to coke works and hospital admissions for respiratory and cardiovascular disease in England and Wales

BACKGROUND

The incidence of hospital admissions for respiratory and cardiovascular diseases in areas close to operating coke works in England and Wales was investigated.

METHODS

A small area study using distance from source as a proxy for exposure was undertaken in subjects aged 65 or over and children under 5 years within 7.5 km of four coke works (1991 estimated populations 87 760 and 43 932, respectively). The main outcome measures were emergency hospital admissions in 1992/3-1994/5 with a primary diagnosis of coronary heart disease (ICD 410-414), stroke (ICD 431-438), all respiratory diseases (ICD 460-519), chronic obstructive pulmonary disease (ICD 491-492), and asthma (ICD 493) in those aged 65 or over, and all respiratory and asthma admissions in children under 5 years of age.

RESULTS

At age 65 or over the combined estimate of relative risk with proximity to coke works (per km) ranged from 0.99 (95% CI 0.90 to 1.09) for chronic obstructive pulmonary disease to 1.03 (95% CI 0.94 to 1.13) for asthma. For children under 5 years the combined estimate of risk was 1.08 (95% CI 0.98 to 1.20) for all respiratory disease and 1.07 (95% CI 0.98 to 1.18) for asthma. There was evidence of significant heterogeneity in risk estimates between coke work groups, especially in children under 5 years (p<0.001 and p=0.004 for respiratory disease and asthma, respectively). For the Teesside coke works in North East England the relative risk with proximity (per km) was 1.09 (95% CI 1.06 to 1.12) for respiratory disease and 1.09 (95% CI 1.04 to 1.15) for asthma.

CONCLUSIONS

No evidence overall was found for an association between hospital admissions and living near operational coke works in England and Wales. Trends of a higher risk of hospital admission for respiratory disease and asthma among children with proximity to the Teesside plant require further investigation.

Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997

The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.

Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997

The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.

Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997

The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.

Perinatal and infant mortality and low birth weight among residents near cokeworks in Great Britain

With growing evidence of the adverse health effects of air pollution--especially fine particulates--investigators must concentrate on the fetus, neonate, and infant as potentially vulnerable groups. Cokeworks are a major source of smoke and sulfur dioxide. In the current study, the authors investigated whether populations residing near cokeworks had a higher risk of adverse perinatal and infant outcomes. Zones of 7.5-km radius around 22 cokeworks in Great Britain were studied, within which the authors assumed that exposure declined from highest levels within 2 km to background levels. Routinely recorded birth and death data for Great Britain during the period 1981-1992 were analyzed. Each individual record had a postcode that referred to a small geographical area of typically 15-17 addresses. The authors calculated expected numbers on the basis of regional rates, stratified by year, sex, and a small-area socioeconomic deprivation score. For all cokeworks combined, the observed/expected ratio (95% confidence intervals within parentheses) within 2 km of cokeworks was 1.00 (0.95, 1.06) for low-birth-weight (i.e., < 2,500 g) infants; 0.94 (0.78, 1.12) for still births; 0.95 (0.83, 1.09) for infant mortality; 0.86 (0.72, 1.03) for neonatal mortality; 1.10 (0.90, 1.33) for postneonatal mortality; 0.79 (0.30, 1.46) for respiratory postneonatal mortality; and 1.07 (0.77, 1.43) for postneonatal Sudden Infant Death Syndrome. Respiratory postneonatal mortality was low throughout the entire 0-7.5-km study area (observed/expected = 0.74 [0.61, 0.88]). There was no statistically significant decline in risk with distance from cokeworks for any of the outcomes studied. The authors concluded that there was no evidence of an increased risk of low birth weight, stillbirths, and/or neonatal mortality near cokeworks, and there was no strong evidence for any association between residence near cokeworks and postneonatal mortality. One must remember, however, the limited statistical power of the study to detect small risks.