Cancer incidence and mortality near the Baglan Bay petrochemical works, South Wales

Effects of Benzene: Hematological and Hypersensitivity Manifestations in Resident Living in Oil Refinery Areas

Literature is teeming with publications on industrial pollution. Over the decades, the main industrial pollutants and their effects on human health have been widely framed. Among the various compounds involved, benzene plays a leading role in the onset of specific diseases. Two systems are mainly affected by the adverse health effects of benzene exposure, both acute and chronic: the respiratory and hematopoietic systems. The most suitable population targets for a proper damage assessment on these systems are oil refinery workers and residents near refining plants. Our work fits into this area of interest with the aim of reviewing the most relevant cases published in the literature related to the impairment of the aforementioned systems following benzene exposure. We perform an initial debate between the two clinical branches that see a high epidemiological expression in this slice of the population examined: residents near petroleum refinery areas worldwide. In addition, the discussion expands on highlighting the main immunological implications of benzene exposure, finding a common pathophysiological denominator in inflammation, oxidative stress, and DNA damage, thus helping to set the basis for an increasingly detailed characterization aimed at identifying common molecular patterns between the two clinical fields discussed.

Cancer Incidence and Mortality among Petroleum Industry Workers and Residents Living in Oil Producing Communities: A Systematic Review and Meta-Analysis

Petroleum extraction and refining are major sources of various occupational exposures and of air pollution and may therefore contribute to the global cancer burden. This systematic review and meta-analysis is aimed at evaluating the cancer risk in petroleum-exposed workers and in residents living near petroleum facilities. Relevant studies were identified and retrieved through PubMed and Web of Science databases. Summary effect size (ES) and 95% confidence intervals (CI) were analysed using random effect models, and heterogeneity across studies was assessed (I2). Overall, petroleum industry work was associated with an increased risk of mesothelioma (ES = 2.09, CI: 1.58-2.76), skin melanoma (ES = 1.34, CI: 1.06-1.70 multiple myeloma (ES =1.81, CI: 1.28-2.55), and cancers of the prostate (ES = 1.13, Cl: 1.05-1.22) and urinary bladder (ES = 1.25, CI: 1.09-1.43) and a decreased risk of cancers of the esophagus, stomach, colon, rectum, and pancreas. Offshore petroleum work was associated with an increased risk of lung cancer (ES = 1.20; 95% CI: 1.03-1.39) and leukemia (ES = 1.47; 95% CI: 1.12-1.92) in stratified analysis. Residential proximity to petroleum facilities was associated with childhood leukemia (ES = 1.90, CI: 1.34-2.70). Very few studies examined specific exposures among petroleum industry workers or residents living in oil producing communities. The present review warrants further studies on specific exposure levels and pathways among petroleum-exposed workers and residents living near petroleum facilities.

Association between leukemia incidence and mortality and residential petrochemical exposure: A systematic review and meta-analysis

BACKGROUND

The global burden of leukemia, which grew by 19% from 2007 to 2017, poses a threat to human development and global cancer control. Factors contributing to this growth include massive industrial pollution, especially from large-scale petrochemical industry complexes (PICs). Globally, around 700 PICs are continuously operating. Data on the impact of PICs on leukemia incidence and mortality in residents are sparse and inconsistent.

OBJECTIVE

To determine the association between residential exposure to PICs and leukemia incidence and mortality using systematic review and meta-analysis.

METHODS

The studies were identified through seven databases (Clinical Key, Cochrane Library, EBSCOhost, Embase, PubMed, ScienceDirect, and Web of Science). We screened the eligibility of studies using following criteria: (1) observational studies that focused on residential exposure to PICs; (2) exposure group that was defined as residents living close to PICs; (3) outcome that was defined as all leukemia incidence and mortality; and (4) available population data. We applied the Grading of Recommendations Assessment, Development, and Evaluation to assess the certainty of evidence. The random-effects model used to estimate the pooled effects in the meta-analysis.

RESULTS

We identified thirteen epidemiologic studies (including eleven for leukemia incidence, one for leukemia mortality, and one for both), covering 125,580 individuals from Croatia, Finland, Italy, Serbia, Spain, Sweden, Taiwan, the United Kingdom, and the United States. We found moderate certainty of evidence indicated the risk of leukemia incidence (relative risk [RR] = 1.18; 95% CI = 1.03-1.35) and mortality (RR = 1.26; 95% CI = 1.10-1.45) in residents living close to PICs. Our subgroup analysis found increased RRs for leukemia incidence in studies using distance-based exposure indicator (RR = 1.11; 95% CI = 1.00-1.23), and with longer follow-up periods (RR = 1.24; 95% CI = 1.06-1.45).

CONCLUSION

Our analysis provides low-certainty evidence of increased leukemia incidence and moderate-certainty evidence of increased leukemia mortality among residents living close to PICs. While the global petrochemicals sector is growing, our findings suggest the need to consider disease prevention and pollution control measures during the development of PICs.

Proximity to Oil Refineries and Risk of Cancer: A Population-Based Analysis

Background

The association between proximity to oil refineries and cancer rate is largely unknown. We sought to compare the rate of cancer (bladder, breast, colon, lung, lymphoma, and prostate) according to proximity to an oil refinery in Texas.

Methods

A total of 6 302 265 persons aged 20 years or older resided within 30 miles of an oil refinery from 2010 to 2014. We used multilevel zero-inflated Poisson regression models to examine the association between proximity to an oil refinery and cancer rate.

Results

We observed that proximity to an oil refinery was associated with a statistically significantly increased risk of incident cancer diagnosis across all cancer types. For example, persons residing within 0-10 (risk ratio [RR] = 1.13, 95% confidence interval [CI] = 1.07 to 1.19) and 11-20 (RR = 1.05, 95% CI = 1.00 to 1.11) miles were statistically significantly more likely to be diagnosed with lymphoma than individuals who lived within 21-30 miles of an oil refinery. We also observed differences in stage of cancer at diagnosis according to proximity to an oil refinery. Moreover, persons residing within 0-10 miles were more likely to be diagnosed with distant metastasis and/or systemic disease than people residing 21-30 miles from an oil refinery. The greatest risk of distant disease was observed in patients diagnosed with bladder cancer living within 0-10 vs 21-30 miles (RR = 1.30, 95% CI = 1.02 to 1.65), respectively.

Conclusions

Proximity to an oil refinery was associated with an increased risk of multiple cancer types. We also observed statistically significantly increased risk of regional and distant/metastatic disease according to proximity to an oil refinery.

Health risks for the population living near petrochemical industrial complexes. 1. Cancer risks: A review of the scientific literature

Petrochemical complexes and oil refineries are well known sources of a wide range of environmental pollutants. Consequently, the potential harmful health effects of living near these facilities is a topic of concern among the population living in the neighborhood. Anyhow, the number of studies carried out on this issue is rather limited and, in some cases, results are even slightly contradictory. The present Review was aimed at assessing whether living in the vicinity of petrochemical industries and oil refineries is associated with a higher incidence of cancer and cancer mortality. In this sense, up to 23 investigations were found in PubMed and Scopus databases. According to the type of cancer, leukemia and other hematological malignancies were reported as the main types of cancer for populations living in the neighborhood of petrochemical industries. This was concluded based on studies performed in Taiwan, Spain, United Kingdom, Italy and Nigeria. In contrast, no association was found in 4 different investigations conducted in Sweden, Finland and USA with the same purpose. Other scientific studies reported a high incidence of lung and bladder cancer in Taiwan, Italy and USA, as well as an excess mortality of bone, brain, liver, pleural, larynx and pancreas cancers in individuals living near petrochemical complexes from Taiwan, Spain, Italy, United Kingdom and USA. Thus, human exposure to certain carcinogenic pollutants emitted from petrochemical industries might increase the incidence of some cancers and cancer mortality. Anyway, since the limited number of investigations conducted until now, further studies are required in order to corroborate -in a more generalized way-this conclusion.

A systematic review and meta-analysis of haematological malignancies in residents living near petrochemical facilities

BACKGROUND

The petrochemical industry is a major source of hazardous and toxic air pollutants that are recognised to have mutagenic and carcinogenic properties. A wealth of occupational epidemiology literature exists around the petrochemical industry, with adverse haematological effects identified in employees exposed to 'low' concentrations of aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylene). Releases from the petrochemical industry are also thought to increase the risk of cancer incidence in fenceline communities. However, this emerging and at times inconclusive evidence base remains fragmented. The present study's aim was to conduct a systematic review and meta-analysis of epidemiological studies investigating the association between incidences of haematological malignancy and residential exposure to the petrochemical industry.

METHODS

Epidemiological studies reporting the risk of haematological malignancies (Leukaemia, Hodgkin's lymphoma, Non-Hodgkin's lymphoma, and Multiple myeloma) were included where the following criteria were met: (i) Cancer incidence is diagnosed by a medical professional and coded in accordance to the International Classification of Diseases; (ii) A clear definition of fenceline communities is provided, indicating the proximity between exposed residents and petrochemical activities; and (iii) Exposure is representative of normal operating conditions, not emergency events. Two investigators independently extracted information on study characteristics and outcomes in accordance with PRISMA and MOOSE guidelines. Relative risks and their 95% confidence intervals were pooled across studies for the four categories of haematological malignancy, using a random effects meta-analysis.

RESULTS

The systematic review identified 16 unique studies, which collectively record the incidence of haematological malignancies across 187,585 residents living close to a petrochemical operation. Residents from fenceline communities, less than 5 km from a petrochemical facility (refinery or manufacturer of commercial chemicals), had a 30% higher risk of developing Leukaemia than residents from communities with no petrochemical activity. Meanwhile, the association between exposure and rarer forms of haematological malignancy remains uncertain, with further research required.

CONCLUSIONS

The risk of developing Leukaemia appears higher in individuals living near a petrochemical facility. This highlights the need for further policy to regulate the release of carcinogens by industry.

Residential exposure to petrochemical industrial complexes and the risk of leukemia: A systematic review and exposure-response meta-analysis

Exposure to chemicals produced by petrochemical industrial complexes (PICs), such as benzene, ionizing radiation, and particulate matters, may contribute to the development of leukemia. However, epidemiological studies showed controversial results. This systematic review and meta-analysis aimed to summarize the association between residential exposure to PICs and the risk of leukemia incidence, focusing on exposure-response effects. We searched PubMed, Embase, Web of Science, and Cochrane Library databases for studies published before September 1st, 2019. Observational studies investigating residential exposure to PICs and the risk of leukemia were included. The outcome of interest was the incidence of leukemia comparing to reference groups. Relative risk (RR) was used as the summary effect measure, synthesized by characteristics of populations, distance to PICs, and calendar time in meta-regression. We identified 7 observational studies, including 2322 leukemia cases and substantial reference groups, in this meta-analysis. Residential exposure to PICs within a maximal 8-km distance had a 36% increased risk of leukemia (pooled RR = 1.36, 95% CI = 1.14-1.62) compared to controls, regardless of sex and age. In terms of leukemia subtypes, residential exposure to PICs was associated with the risks of acute myeloid leukemia (AML, pooled RR = 1.61, 95% CI = 1.12-2.31) and chronic lymphocytic leukemia (CLL, pooled RR = 1.85, 95% CI = 1.11-6.42). In meta-regression, the positive association occurred after 10 years of follow-up with a pooled RRs of 1.21 (95% CI = 1.02-1.44) and then slightly increased to 1.77 (95% CI = 1.35-2.33) at 30 years after follow-up. No effect modification was found by sex, age, and geographic locations.

Regional inequalities in benzene exposures across the European petrochemical industry: A Bayesian multilevel modelling approach

BACKGROUND

Pollutants released from the petrochemical industry are thought to increase the risk of mortality in fence-line communities, yet the results from previous studies are often inconsistent and lack a global perspective, hampered by the absence of cohesive cross-country research.

OBJECTIVES

To provide the first Pan-European analysis of benzene exposures from the petrochemical industry, connecting polluting practices to pollution episodes and disparities in regional mortality rates, identifying the measures of best environmental practice to mitigate adverse outcomes.

METHODS

The activity, classification and location of onshore petrochemical facilities within EU-28 Member States were extracted from the 'European Pollutant Release and Transfer Register' (E-PRTR), which holds records on 31,753 industrial operations for the reporting period of 2007-15. Parent company records were collected from the Moody's Analytics Amadeus database of 487,338 active companies across Europe. The EUROSTAT census provided records of income, life expectancy, and the underlying demographics used to calculate standardised health outcomes based on 9,936 sub-populations within the NUTS2 regions. The European Environment Agency provided ambient concentrations of benzene from 579 air quality stations. Bayesian multilevel models were constructed to account for variability caused by spatial hierarchical structures, uncertainty in the estimates, and to incorporate both individual and group-level influences.

RESULTS

Higher levels of benzene emissions from petrochemical operations, both overall and in terms of specific pollution events, were associated with increased mortality rates for nearby residential populations, particularly in areas with socioeconomic deprivation. We identify uneven patterns of polluting practices within the industry, and locations that require epidemiological studies.

CONCLUSIONS

While petrochemical facilities in all European Union regions are regulated to be compliant with the annual average benzene limit of 5 μg/m3, uneven exposures still present regional health inequalities. We recommend extending benzene regulations to an hourly or daily limit, alongside the strengthening of regulation for other toxic petrochemical releases.

Residents' Self-Reported Health Effects and Annoyance in Relation to Air Pollution Exposure in an Industrial Area in Eastern-Estonia

Eastern Estonia has large oil shale mines and industrial facilities mainly focused on electricity generation from oil shale and shale oil extraction, which produce high air pollution emissions. The "Study of the health impact of the oil shale sector-SOHOS" was aimed at identifying the impacts on residents' health and annoyance due to the industrial processing. First, a population-wide survey about health effects and annoyance was carried out. Second, the total and oil shale sectors' emitted concentrations of benzene, phenol, and PM2.5 were modelled. Third, the differences between groups were tested and relationships between health effects and environmental pollution studied using multiple regression analysis. Compared to the control groups from non-industrial areas in Tartu or Lääne-Viru, residents of Ida-Viru more frequently (p < 0.05) reported wheezing, chest tightness, shortness of breath, asthma attacks, a long-term cough, hypertension, heart diseases, myocardial infarction, stroke, and diabetes. All health effects except asthma were reported more frequently among non-Estonians. People living in regions with higher levels of PM2.5, had significantly higher odds (p < 0.05) of experiencing chest tightness (OR = 1.13, 95% CI 1.02-1.26), shortness of breath (1.16, 1.03-1.31) or an asthma attack (1.22, 1.04-1.42) during the previous year. People living in regions with higher levels of benzene had higher odds of experiencing myocardial infarction (1.98, 1.11-3.53) and with higher levels of phenol chest tightness (1.44, 1.03-2.00), long-term cough (1.48, 1.06-2.07) and myocardial infarction (2.17, 1.23-3.83). The prevalence of adverse health effects was also higher among those who had been working in the oil shale sector. Next to direct health effects, up to a quarter of the residents of Ida-Viru County were highly annoyed about air pollution. Perceived health risk from air pollution increased the odds of being annoyed. Annoyed people in Ida-Viru had significantly higher odds of experiencing respiratory symptoms during the last 12 months, e.g., wheezing (2.30, 1.31-4.04), chest tightness (2.88, 1.91-4.33 or attack of coughing (1.99, 1.34-2.95).

Increased cancers among residents living in the neighborhood of a petrochemical complex: A 12-year retrospective cohort study

This study investigates whether cancers are increased for residents living in the vicinity of a petrochemical complex with coal power plants and refineries. We recruited a residential cohort of 2388 long-term residents aged above 35 years in 2009-2012 who lived within a 40 km radius of the complex. We measured their internal exposure biomarkers of urinary carcinogenic metals and retrospectively compared cancer incidences between those who lived fewer than 10 km from the complex (high exposure, HE) and those who lived more than 10 km from the complex (low exposure, LE). Residents had lived in their respective areas for 12 years, since the complex began operating in mid-1999. This included two periods of operation: 0-9 years and 10-12 years. Crude cumulative incident rates (CIRs) of all cancers were calculated for new cancer cases (ICD-9: 140-165, 170-176, 179-208) recorded in the Taiwan Health Insurance Database over total person-years at risk in each study period. Poisson regression was applied to estimate relative risks for the CIRs of all cancers between HE and LE areas during the 10-12 years since the beginning of the complex's operation, adjusting for age, gender, body mass index, smoking, hepatitis C, and occupational exposure. We found that our study subjects in HE areas had higher urinary carcinogenic metal levels, including As, Cd, Hg, Pb, and V, and higher prevalence rates of hepatitis C than those in LE areas. After the complex had been operating for 10-12 years, SIRs per 1000 person-years for all cancers in HE and LE areas were 4.44 vs. 2.48 for all subjects, 15.2 vs. 4.86 for elder subjects aged above 60 years, and 2.94 vs. 2.71 for female subjects. Correspondingly, the adjusted relative risks of CIRs for all cancers between HE and LE areas were 1.29 (95% CI: 0.99-1.68) for all subjects, 1.52 (1.04-2.22) for elder subjects, 1.41 (1.00-1.97) for female subjects, and 1.91 (1.15-3.19) for female elderly subjects. We conclude that elder and female residents living within 10 km of a petrochemical complex had higher carcinogenic exposure and cancers than those living farther away from the complex after the complex had been operating for 10 years.

Lung cancer mortality of residents living near petrochemical industrial complexes: a meta-analysis

BACKGROUND

Lung cancer, as the leading cause of cancer mortality worldwide, has been linked to environmental factors, such as air pollution. Residential exposure to petrochemicals is considered a possible cause of lung cancer for the nearby population, but results are inconsistent across previous studies. Therefore, we performed a meta-analysis to estimate the pooled risk and to identify possible factors leading to the heterogeneity among studies.

METHODS

The standard process of selecting studies followed the Cochrane meta-analysis guideline of identification, screening, eligibility, and inclusion. We assessed the quality of selected studies using the Newcastle-Ottawa scale. Reported point estimates and 95% confidence intervals were extracted or calculated to estimate the pooled risk. Air quality standards were summarized and treated as a surrogate of exposure to air pollution in the studied countries. Funnel plots, Begg's test and Egger's test were conducted to diagnose publication bias. Meta-regressions were performed to identify explanatory variables of heterogeneity across studies.

RESULTS

A total of 2,017,365 people living nearby petrochemical industrial complexes (PICs) from 13 independent studied population were included in the analysis. The pooled risk of lung cancer mortality for residents living nearby PICs was 1.03-fold higher than people living in non-PIC areas (95% CI = 0.98-1.09), with a low heterogeneity among studies (I 2  = 25.3%). Such effect was stronger by a factor of 12.6% for the year of follow-up started 1 year earlier (p-value = 0.034).

CONCLUSIONS

Our meta-analysis gathering current evidence suggests only a slightly higher risk of lung cancer mortality among residents living nearby PICs, albeit such association didn't receive statistically significance. Reasons for higher risks of early residential exposure to PICs might be attributable to the lack of or less stringent air pollution regulations.

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.

Risk of non-Hodgkin's lymphoma and residential exposure to air pollution in an industrial area in northern Italy: a case-control study

The aim of this study was to evaluate the risk of non-Hodgkin's lymphoma (NHL) in an adult population residing in an area in northern Italy exposed to industrial air pollution from a big power plant, a coke oven, 2 chemical factories, and some minor plants. The design was a population-based case-control study and information about residential history and the main risk factors for NHL was obtained interviewing 133 cases and 279 controls using a structured questionnaire. Three exposure categories (heavy, moderate, and slight) were defined on the basis of the location of the major facilities with respect to the subject residence. NHL risk was not associated either with location or duration of residence in the heavily polluted area. However, the unavoidable limitations of this study prevent us from drawing definitive conclusions.

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.

Annoyance and worry in a petrochemical industrial area--prevalence, time trends and risk indicators

In 1992, 1998, and 2006, questionnaires were sent to stratified samples of residents aged 18–75 years living near petrochemical industries (n = 600–800 people on each occasion) and in a control area (n = 200–1,000). The aims were to estimate the long-term prevalence and change over time of annoyance caused by industrial odour, industrial noise, and worries about possible health effects, and to identify risk indicators. In 2006, 20% were annoyed by industrial odour, 27% by industrial noise (1–4% in the control area), and 40–50% were worried about health effects or industrial accidents (10–20% in the control area). Multiple logistic regression analyses revealed significantly lower prevalence of odour annoyance in 1998 and 2006 than in 1992, while industrial noise annoyance increased significantly over time. The prevalence of worry remained constant. Risk of odour annoyance increased with female sex, worry of health effects, annoyance by motor vehicle exhausts and industrial noise. Industrial noise annoyance was associated with traffic noise annoyance and worry of health effects of traffic. Health-risk worry due to industrial air pollution was associated with female sex, having children, annoyance due to dust/soot in the air, and worry of traffic air pollution.

Mortality due to haematological cancer in cities close to petroleum refineries in Spain

Controversy exists as to whether working or living in the vicinity of a petroleum refinery (RF) increases the risk of haematological cancer (HC). The European Pollutant Release and Transfer Register obliges petroleum refineries to notify their emissions of toxic substances which include carcinogenic substances. Our objective is to determine if living in the proximity of an RF is associated with a greater risk of mortality due to HC in the census tracts (CTs) of the Spanish cities of Bilbao, Cartagena, Castellón, La Coruña, Huelva, and Santa Cruz de Tenerife. This is an ecological study of mortality in the years 1996-2007 which includes 968 CTs with 1,263,371 inhabitants. Exposure has been measured as the distance from the centroid of each CT to the RF. The Besag-York-Mollié autoregressive spatial model has been fitted by R-INLA to estimate the relative risk (RR) and 95 % credible intervals (95 % CrI) for distance in quintiles. The most distant quintile has been taken as the reference. A total of 2,574 persons died of HC. The distances from the CTs to RFs ranged from 0.5 to 22.5 km (median = 7.6 km). All of the RRs for the quintiles of distances in Huelva were greater than 1. Statistically significant excess risk was shown in Cartagena in the nearest CT (1.8 to 6.8 km; RR = 1.43, 95 % CrI 1.02 to 2.02). Radial effects have not been detected between the CT of residence and the petroleum RF in mortality due to HC in any of the cities.

Prostate cancer and industrial pollution Risk around putative focus in a multi-source scenario

BACKGROUND

Prostate cancer is the second most common type of cancer among men but its aetiology is still largely unknown. Different studies have proposed several risk factors such as ethnic origin, age, genetic factors, hormonal factors, diet and insulin-like growth factor, but the spatial distribution of the disease suggests that other environmental factors are involved. This paper studies the spatial distribution of prostate cancer mortality in an industrialized area using distances from each of a number of industrial facilities as indirect measures of exposure to industrial pollution.

MATERIALS AND METHODS

We studied the Gran Bilbao area (Spain) with a population of 791,519 inhabitants distributed in 657 census tracts. There were 20 industrial facilities within the area, 8 of them in the central axis of the region. We analysed prostate cancer mortality during the period 1996-2003. There were 883 deaths giving a crude rate of 14 per 100,000 inhabitants. We extended the standard Poisson regression model by the inclusion of a multiplicative non-linear function to model the effect of distance from an industrial facility. The function's shape combined an elevated risk close to the source with a neutral effect at large distance. We also included socio-demographic covariates in the model to control potential confounding.

RESULTS

We aggregated the industrial facilities by sector: metal, mineral, chemical and other activities. Results relating to metal industries showed a significantly elevated risk by a factor of approximately 1.4 in the immediate vicinity, decaying with distance to a value of 1.08 at 12km. The remaining sectors did not show a statistically significant excess of risk at the source.

DISCUSSION

Notwithstanding the limitations of this kind of study, we found evidence of association between the spatial distribution of prostate cancer mortality aggregated by census tracts and proximity to metal industrial facilities located within the area, after adjusting for socio-demographic characteristics at municipality level.

Cancer incidence in a petrochemical industry area in Sweden

Emissions from petrochemical industries may contain suspected or established carcinogens. As increased incidence of cancer in residential areas close to petrochemical industries has been reported in the literature, we conducted a study of cancer incidence in Stenungsund, Sweden, where petrochemical industries were established in the mid 1960s. A number of cancer cases in the central parts of Stenungsund were collected from the regional cancer registry for each year between 1974 and 2005. In addition to the total number of cases, the numbers of leukemia, lymphoma, liver cancer, lung cancer, and brain cancer were also collected. Expected numbers for each year were calculated based on age- and sex-specific incidence rates in reference areas. Levels of carcinogenic volatile hydrocarbons (VOC) were estimated from measurements and emission data. A dispersion model was used to classify Stenungsund into a "low" and "high" ethylene level area. Standardized Incidence Ratio (SIR) for all cancer for the entire period was 1.02 (95% CI 0.97-1.08). The occurrence of leukemia, lymphoma, and cancer in the central nervous system was slightly lower than expected for the entire period. SIR for lung cancer was 1.37 (95% CI 1.10-1.69), and SIR for liver cancer was 1.50 (0.82-2.53). VOC levels were low. Taking estimated exposure and demographic factors into account, our assessment is that occurrence of cancer was not affected by industrial emissions in any of the studied sites.

A biomarker approach to estimate the daily intake of benzene in non-smoking and smoking individuals in Germany

Owing to its carcinogenic properties, benzene is one of the most important environmental air pollutants. We have applied a simple pharmacokinetic model to estimate the individual daily exposure of persons of the general population to benzene using their urinary excretion of S-phenylmercapturic acid as biomarker of exposure. On the basis of a non-representative convenience sample of the general population, spontaneous urine samples of 43 non-smoking persons, 13 persons with exposure to environmental tobacco smoke (ETS) (as determined by urinary cotinine) and 72 smokers were analyzed for S-phenylmercapturic acid, and benzene exposure was back calculated on the basis of the results. The pharmacokinetic model was based either on estimated daily urinary volume or creatinine excretion. Median daily exposure of non-smokers was calculated to be 47 microg/day (volume-based model) and 63 microg benzene/day (creatinine-based model). ETS-exposed persons had a slightly higher median daily exposure of 65 microg/day (volume-based model) and 72 microg benzene/day (creatinine-based model). The daily exposure of smokers was significantly higher with median values of 491 microg benzene/day (volume-based model) and 693 microg benzene/day (creatinine-based model). Our biomarker-based model gave plausible results for daily benzene exposure that were in good agreement with exposure estimations published earlier. As it is purely based on the determination of individual internal dose, our model provides a powerful tool for the risk assessment of environmental benzene.

Environmental exposure to emissions from petrochemical sites and lung cancer: the lower Mississippi interagency cancer study

To investigate potential links between environmental exposure to petrochemical plant emissions and lung cancer, a population-based case-control study (LMRICS) was conducted in eleven Louisiana parishes bordering the Mississippi River. Cases and age, gender, and race-matched controls were interviewed regarding potential risk factors. Residential history was geocoded to provide indices of long-term proximity to industrial sites. Cases were more likely to have lived near a petrochemical site. Models adjusted for other risk factors, however, showed small or no association with lung cancer (odds ratio for residence within a half-mile of a site = 1.10, 95% confidence interval 0.58-2.08). While associations were strongest for exposures exceeding 15 years, none approached statistical significance and there was no clear dose-response across exposure duration, distance categories, or when sites were grouped according to carcinogenicity rating of chemical releases. Residential proximity to petrochemical plants along the lower Mississippi thus showed no significant association with lung cancer.

Chronic diseases and early exposure to airborne mixtures: Part III. Potential origin of pre-menopausal breast cancers

This is the third in a series dealing with chronic diseases and early exposure to airborne mixtures from industrial releases. The purpose of this study is to increase the understanding of previously unconsidered factors in the physical environment potentially acting as risk factors for female breast cancer. Data are from the Environmental Quality Database containing lifetime residential records for about 20,000 cases, with 1 of 15 cancers and about 5000 controls. Subjects resided within 25 km of all kraft mills, sulfite mills, coke ovens, oil refineries, copper, nickel and lead/zinc smelters operating in Canada in 1967-1970, and were aged <31 years. Subjects are exposed at home to simultaneous counter-current plumes of dioxin congeners and dimethyl sulfate (DMS) during the exposure period. DMS concentration increases with time of flight from the source and [SO(2)] at 2 km. For all source types the number of cancers in an age cohort declines as the age of the cohort increases. The number of cases less than the median distance is less than the number of cases greater than the median distance. This supports the presence of a new source of risk with an origin in the plume. The crude rate of breast cancer, averaged over the 25 km of the study area for each age cohort <31 years of age, as well as source type, is least when the conditions of initial exposure are [SO(2)] > or = [DMS] and increases as [DMS] increases. The probability of an adverse effect from early, intermittent and simultaneous exposure to Dioxin and DMS, manifesting as a breast cancer after a latency period of as little as 26 years, is a function of age of first exposure, distance from the source and source type. The most susceptible age cohorts are the youngest.

Leukaemia incidence in people living close to an oil refinery

OBJECTIVES

To assess the incidence of leukaemia in an area downwind of a large oil refinery emitting carcinogenic volatile organic compounds (VOCs) including benzene.

METHODS

Using a dispersion model and the prevailing wind direction, two parishes with about 5000 inhabitants were a priori considered to be exposed to VOCs from the refinery. Numbers of observed and expected leukaemia cases in 1975-2004 were calculated using regional sex- and age-specific incidence rates. In addition, five nearby parishes (12000 inhabitants), considered unaffected by the emissions, served as a local reference area. Based on emission data, dispersion modelling and VOC measurements, the refinery's contribution to the population's exposure to carcinogenic VOCs was estimated. Published "unit risks" for carcinogenic VOCs were used to estimate the expected excess leukaemia risk.

RESULTS

The incidence of leukaemia in the "exposed parishes" was significantly increased in 1975-2004 (33 cases v. 22 expected cases), owing to an increase in the last 10-year period, from 1995 to 2004 (19 cases v. 8.5 expected cases). The leukaemia incidence in the local control area was normal (50 cases v. 56 expected cases). The estimated contribution from the refinery to VOC concentrations was, however, only about 2 microg/m(3) (yearly average) for benzene, 2 microg/m(3) for ethylene, 0.5 microg/m(3) for 1,3-butadiene and 5 microg/m(3) for propene. Calculations of expected excess risk using published risk estimates would indicate a much lower excess risk in the exposed parishes.

CONCLUSIONS

Using risk estimates extrapolated from high-level exposure, we would not expect an increase of leukaemia at low exposure to VOC emissions. Nevertheless, the clear elevation of leukaemia in the priori selected, exposed parishes was remarkable. Our finding may reflect a causal association due to emissions, but it could also be due to unknown confounding, or chance.

Study of non-Hodgkin's lymphoma mortality associated with industrial pollution in Spain, using Poisson models

Background

Non-Hodgkin's lymphomas (NHLs) have been linked to proximity to industrial areas, but evidence regarding the health risk posed by residence near pollutant industries is very limited. The European Pollutant Emission Register (EPER) is a public register that furnishes valuable information on industries that release pollutants to air and water, along with their geographical location.

This study sought to explore the relationship between NHL mortality in small areas in Spain and environmental exposure to pollutant emissions from EPER-registered industries, using three Poisson-regression-based mathematical models.

Methods

Observed cases were drawn from mortality registries in Spain for the period 1994–2003. Industries were grouped into the following sectors: energy; metal; mineral; organic chemicals; waste; paper; food; and use of solvents. Populations having an industry within a radius of 1, 1.5, or 2 kilometres from the municipal centroid were deemed to be exposed. Municipalities outside those radii were considered as reference populations.

The relative risks (RRs) associated with proximity to pollutant industries were estimated using the following methods: Poisson Regression; mixed Poisson model with random provincial effect; and spatial autoregressive modelling (BYM model).

Results

Only proximity of paper industries to population centres (>2 km) could be associated with a greater risk of NHL mortality (mixed model: RR:1.24, 95% CI:1.09–1.42; BYM model: RR:1.21, 95% CI:1.01–1.45; Poisson model: RR:1.16, 95% CI:1.06–1.27). Spatial models yielded higher estimates.

Conclusion

The reported association between exposure to air pollution from the paper, pulp and board industry and NHL mortality is independent of the model used. Inclusion of spatial random effects terms in the risk estimate improves the study of associations between environmental exposures and mortality.

The EPER could be of great utility when studying the effects of industrial pollution on the health of the population.

Association of childhood leukemia with residential exposure to petrochemical air pollution in taiwan

To investigate the relationship between petrochemical air pollution and childhood leukemia (19 yr of age or younger), the authors conducted a matched case-control study using childhood deaths that occurred in Taiwan from 1995 through 2005. Data on all eligible childhood leukemia deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of children who died from causes other than neoplasms or diseases that were not associated with respiratory problems. The controls were pair matched to the cases by sex, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. The proportion of a municipality's total population employed in the petrochemical industry in a municipality was used as an indicator of a resident's exposure to air emissions from the petrochemical industry. The subjects were divided into three levels (< or =25th percentile; 25th-75th percentile; > 75th percentile) according to the levels of the index just described. After controlling for possible confounders, results showed that children who lived in the group of municipalities characterized by the highest levels of petrochemical air pollution had a statistically significant higher risk of developing leukemia than the group that lived in municipalities with the lowest petrochemical air pollution levels. The results of this study shed important light on the relationship between the Taiwan petrochemical industry and human health risks.

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.

Description of industrial pollution in Spain

BACKGROUND

Toxic substances released into the environment (to both air and water) by many types of industries might be related with the occurrence of some malignant tumours and other diseases. The publication of the EPER (European Pollutant Emission Register) Spanish data allows to investigate the presence of geographical mortality patterns related to industrial pollution. The aim of this paper is to describe industrial air and water pollution in Spain in 2001, broken down by activity group and specific pollutant, and to plot maps depicting emissions of carcinogenic substances.

METHODS

All information on industrial pollution discharge in 2001 was drawn from EPER-Spain public records provided by the European Commission server. We described the distribution of the number of industries and amounts discharged for each pollutant, as well as emission by pollutant group and the industrial activities associated with each pollutant. Maps of Spain were drawn up, with UTM coordinates being used to plot pollutant foci, and circles with an area proportional to the emission to depict pollution emission values.

RESULTS

The EPER-Spain contained information on 1,437 industrial installations. The industrial plants that discharge pollutant substances into air and water above the pollutant-specific EPER threshold were mainly situated in the Autonomous Regions of Aragon, Andalusia and Catalonia and in Catalonia, the Basque Country and Andalusia respectively. Pollution released in 2001 into air approached 158 million Mt. Emissions into water were over 8 million Mt.

CONCLUSION

A few single industrial plants are responsible for the highest percentage of emissions, thus rendering monitoring of their possible health impact on the surrounding population that much simpler. Among European countries Spain is the leading polluter in almost one third of all EPER-registered pollutant substances released into the air and ranks among the top three leading polluters in two-thirds of all such substances. Information obtained through publication of EPER data means that the possible consequences of reported pollutant foci on the health of neighbouring populations can now be studied.

Residential exposure to petrochemicals and the risk of leukemia: using geographic information system tools to estimate individual-level residential exposure

The authors conducted a population-based, case-control study in Kaohsiung, southern Taiwan, Republic of China, to investigate the association between residential petrochemical exposure and leukemia risk among subjects 29 years of age and younger. Between November 1997 and June 2003, 171 cases and 410 controls matched for age and sex were recruited. Since assessment of petrochemical impacts depends on accurate exposure estimates, the authors developed a procedure using geographic information system tools to assign subjects' exposure. The resulting individual-level exposure estimates (the exposure opportunity score) are an integrated exposure measure that accounts for subjects' mobility, length of stay at each residence, distance to petrochemical plant(s), monthly prevailing wind direction, and multiple petrochemical pollution sources. Different conditional logistic regression models were fitted for subjects aged 0-19 and 20-29 years to evaluate separately childhood versus adulthood leukemia. No overall association was observed for the younger age group. However, residential petrochemical exposure was a significant risk factor for leukemia for the older age group. For one unit of increase in the log-transformed exposure opportunity score, the adjusted odds ratio was 1.54 (95 percent confidence interval: 1.14, 2.09). This study illustrates the utility of geographic information system tools for providing refined exposure estimates for residential exposure to petrochemical pollution.

Acute childhood leukaemia and environmental exposure to potential sources of benzene and other hydrocarbons; a case-control study

AIM

To analyse the association between potential environmental exposure to hydrocarbons and the risk of acute childhood leukaemia.

METHODS

A hospital based multicentre case control study, stratified on centre, age, and sex, with 280 leukaemia cases and 285 controls was carried out. Data were collected by a standardised interview of the mothers.

RESULTS

No clear association was seen between maternal occupational exposure to hydrocarbons during pregnancy and leukaemia, or between residential traffic density and leukaemia. There was an association between dwellings neighbouring a petrol station or a repair garage during childhood and the risk of childhood leukaemia (OR 4.0, 95% CI 1.5 to 10.3), with a duration trend. The association, which appeared particularly strong for acute non-lymphocytic leukaemia (OR 7.7, 95% CI 1.7 to 34.3), was not altered by adjustment for potential confounding factors.

CONCLUSIONS

Results showed an association between acute childhood leukaemia and dwellings neighbouring auto repair garages and petrol stations, which are benzene emitting sources. These findings could be due to chance, although the strength of the association and the duration trend are arguments for a causal association.

Mortality patterns among residents in Louisiana's industrial corridor, USA, 1970-99

BACKGROUND

Because of the high concentration of oil refining and petrochemical facilities, the industrial area of the lower Mississippi River of South Louisiana has been termed the Industrial Corridor and has frequently been referred to as the "Cancer Corridor".

AIMS

To quantitatively assess the "Cancer Corridor" controversy based on mortality data available in the public domain, and to identify potential contributing factors to the observed differences in mortality.

METHODS

Age adjusted mortality rates were calculated for white and non-white males and females in the Industrial Corridor, Louisiana, and the United States for the time periods 1970-79, 1980-89, and 1990-99.

RESULTS

All-cause mortality and all cancer combined for white males in the Industrial Corridor were significantly lower than the corresponding Louisiana population while Louisiana had significantly higher rates than the US population for all three time periods. Cancer of the lung was consistently higher in the Industrial Corridor region relative to national rates but lower than or similar to Louisiana. Non-respiratory disease and cerebrovascular disease mortality for white males in the Industrial Corridor were consistently lower than either Louisiana or the USA. However, mortality due to diabetes and heart disease, particularly during the 1990s, was significantly higher in the Industrial Corridor and Louisiana when compared to the USA. Similar mortality patterns were observed for white females. The mortality for non-white males and females in the Industrial Corridor was generally similar to the corresponding populations in Louisiana. There were no consistent patterns for all cancer mortality combined. Stomach cancer was increased among non-whites in both the Industrial Corridor and Louisiana when compared to the corresponding US data. Mortality from diabetes and heart disease among non-whites was significantly higher in the Industrial Corridor and Louisiana than in the USA.

CONCLUSIONS

Mortality rates in the Industrial Corridor area were generally similar to or lower than the State of Louisiana, which were increased compared to the United States. Contrary to prior public perceptions, mortality due to cancer in the Industrial Corridor does not exceed that for the State of Louisiana.

L’analyse de cluster en épidémiologie géographique : utilisation de plusieurs méthodes statistiques et comparaison de leurs résultats

BACKGROUND

The increasing interest in environmental epidemiology has been followed by the development of many statistical tests for detecting disease clustering near a point source. The objectives of this study were to compare several tests to detect disease clustering, among which modelisation using Markov Chain Monte Carlo methods.

METHODS

We compared six statistical methods for detecting disease clustering of bladder cancer around an industrial centre of Isère (France) for the period 1983-1997: Stone's test, score test, and two log-linear modelisations (with and without corrections for extra-Poisson variations) using two ways of parameters estimation (maximum likelihood and Markov Chain Monte Carlo methods).

RESULTS

The results of the Stone test and the score test are not in favour of a higher risk of bladder cancer around the considered point source. The conclusions brought by the log linear modelisations are the same, but the results obtained using the Markov Chain Monte Carlo Method are very dependant of prior distributions determined for the different parameters.

CONCLUSION

Markov Chain Monte Carlo methods, which allow taking into account complex geographical effects, seem well adapted to cluster analysis in geographical epidemiology. However, they remain difficult to implement.

Lymphohaematopoietic system cancer incidence in an urban area near a coke oven plant: an ecological investigation

AIMS

To evaluate the incidence risk of lymphohaematopoietic cancers for the 1986-94 period in Cornigliano, a district of Genoa (Italy), where a coke oven is located a few hundred metres from the residential area.

METHODS

The whole of Genoa and one of its 25 districts (Rivarolo) were selected as controls. The trend of risk around the coke oven was evaluated via Stone's method, while the geographic pattern of such risks across the Cornigliano district was evaluated by computing full Bayes estimates of standardised incidence ratio (FBE-SIR).

RESULTS

In males, elevated relative risks (RR) were observed for all lymphohaematopoietic cancers (RR 1.7 v Rivarolo and 1.6 v Genoa), for NHL (RR 2.4 v Rivarolo and 1.7 v Genoa), and for leukaemia (RR 2.4 v Rivarolo and 1.9 v Genoa). In females, statistically non-significant RR were observed. In males no excess of risk was found close to the coke oven. In females, a rising risk for NHL was observed approaching the plant, although statistical significance was not reached, while the risk for leukaemia was not evaluable due to the small number of cases. Analysis of the geographic pattern of risk suggested the presence of a cluster of NHL in both sexes in the eastern part of the district, where a foundry had been operational until the early 1980s. A cluster of leukaemia cases was observed in males in a northern part of the area, where no major sources of benzene seemed to be present.

CONCLUSIONS

The estimated risks seem to be slightly or not at all related to the distance from the coke oven. The statistically significant higher risks observed in males for NHL and leukaemia, and the clusters of leukaemia in males and of NHL in both sexes deserve further investigations in order to trace the exposures associated with such risks.

Community reappraisal of the perceived health effects of a petroleum refinery

This paper presents results from a study of the community health impacts of a petroleum refinery in Oakville, Ontario in Canada. The research is informed by the environmental stress and coping literatures and the focus is on community reappraisal of the refinery's impacts before and after the implementation of a substantive odour reduction initiative on the part of the refinery operators. Community health surveys were conducted in 1992 (n = 391) and 1997 (n = 427) to examine changes in odour perception and annoyance and self-reported health status attributable to the odour reduction plan. The findings reported here suggest an on-going process of cognitive reappraisal, whereby negative perceptions and concerns decreased between 1992 and 1997. Irrespective of this positive reappraisal of the refinery efforts, those living close to the refinery continue to report negative health impacts. A strong mediating effect of odours on the refinery exposure-symptom reporting relationship was confirmed by our results. While the relationship between odour perception and symptom reporting indicates the importance of odour perception and annoyance as the principal mechanism mediating ill-health reporting, the plausibility of other causal pathways is recognized. Residents' sensitivity to the negative effects of the refinery on their health and the health of their children suggests a psychosocial reaction to the environmental stress associated with perceived and actual refinery emissions.

Cancer risk associated with residential proximity to industrial sites: a review

In this study, the authors sought to review available epidemiologic studies of cancer risk and its association with residence in a neighborhood characterized by industrial sites and to discuss options for future study design. The authors attempted to identify all case-control studies published from January 1980 through July 1997 in which investigators examined exposure resulting from residential proximity to an industrial site neighborhood relative to an increased risk of lung, urinary tract, and lymphohematopoietic malignancies. During these years, some authors reported significant associations between lung cancer risk and residential proximity to (a) smelters, (b) complex industrial areas, and (c) other localized emission sources. There was some evidence that leukemia and lymphomas occurred in the neighborhoods that contained industrial sites.

Statistical issues in the analysis of disease mapping data

In this paper we discuss a number of issues that are pertinent to the analysis of disease mapping data. As an illustrative example we consider the mapping of larynx cancer across electoral wards in the North West Thames region of the U.K. Bayesian hierarchical models are now frequently employed to carry out such mapping. In a typical situation, a three-stage hierarchical model is specified in which the data are modelled as a function of area-specific relative risks at stage one; the collection of relative risks across the study region are modelled at stage two; and at stage three prior distributions are assigned to parameters of the stage two distribution. Such models allow area-specific disease relative risks to be 'smoothed' towards global and/or local mean levels across the study region. However, these models contain many structural and functional assumptions at different levels of the hierarchy; we aim to discuss some of these assumptions and illustrate their sensitivity. When relative risks are the endpoint of interest, it is common practice to assume that, for each of the age-sex strata of a particular area, there is a common multiplier (the relative risk) acting upon each of the stratum-specific risks in that area; we will examine this proportionality assumption. We also consider the choices of models and priors at stages two and three of the hierarchy, the effect of outlying areas, and an assessment of the level of smoothing that is being carried out. For inference, we concentrate on the description of the spatial variability in relative risks and on the association between the relative risks of larynx cancer and an area-level measure of socio-economic status.

Lymphohaematopoietic malignancy around all industrial complexes that include major oil refineries in Great Britain

OBJECTIVES

To examine the incidence of lymphohaematopoietic malignancy around industrial complexes that include major oil refineries in Great Britain after recent public and scientific concern of possible carcinogenic hazards of emissions from the petrochemical industry.

METHODS

Small area study of the incidence of lymphohaematopoietic malignancies, 1974-91, within 7.5 km of all 11 oil refineries (grouped into seven sites) in Great Britain that were operational by the early 1970s and processed more than two million tonnes of crude oil in 1993.

RESULTS

Combined analysis of data from all seven sites showed no significant (p < 0.05) increase in risk of these malignancies within 2 km or 7.5 km. Hodgkin's lymphoma, but no other malignancy, showed evidence (p = 0.02) of a decline in risk with distance from refineries, but there was an apparent deficit of cases of multiple myeloma near the refineries (p = 0.04).

CONCLUSION

There was no evidence of association between residence near oil refineries and leukaemias, or non-Hodgkin's lymphoma. A weak positive association was found between risk of Hodgkin's disease and proximity to major petrochemical industry, and a negative association with multiple myeloma, which may be chance findings within the context of multiple statistical testing.

Small area study of mortality among people living near multiple sources of air pollution

OBJECTIVE

In the area of Malagrotta, a suburb of Rome (Italy), a large waste disposal site, a waste incinerator plant, and an oil refinery plant became operational in the early 1960s and have represented three major sources of air pollution. To evaluate the potential health risk due to airborne contamination around these point sources, a small area analysis of mortality was conducted. Cancer of the liver, larynx, lung, kidney, lymphatic, and haematopoietic systems were evaluated.

METHODS

Sex and age specific mortality (1987-93) and population denominators (1991) were available for the census tracts of the metropolitan area of Rome. Standardised mortality ratios (SMRs) were computed separately for males and females in bands of increasing distance from the plants, up to a radius of 10 km. Stone's test for the decline in risk with distance was performed with increments in radius of 1 km; SMRs were also computed after adjusting for a four level index of socioeconomic status.

RESULTS

No overall excess or decline in risk with distance was found for liver, lung, and lymphohaematopoietic cancers in either sex. For laryngeal cancer, an increased but not significant risk was found at 0-3 km and at 3-8 km. A significant decline with distance in mortality from laryngeal cancer was found among men (p = 0.03); the trend remained after adjusting for the socioeconomic index (p = 0.06).

CONCLUSIONS

The study showed no association between proximity to the industrial sites and mortality for most of the several conditions considered. However, mortality from laryngeal cancer declined with distance from the sources of pollution. This result is interesting, as previous findings of an increased risk of laryngeal cancer near incinerators have been controversial.

Lung cancer, proximity to industry, and poverty in northeast England

This study assesses whether deprived populations living close to industry experience greater mortality from lung cancer than populations with comparable socioeconomic characteristics living farther away. Mortality data, census data, a postal survey of living circumstances, historic and contemporary data on air quality and a historic land-use survey were used. Analysis was based on two conurbations in England, Teesside and Sunderland. Housing estates in Teesside were selected based on socioeconomic criteria and distinguished by proximity to steel and chemical industries; they were grouped into three zones: near (A), intermediate (B), and farther (C), with a single zone in Sunderland. We included 14,962 deaths in 27 estates. Standardized mortality ratios (SMR) for lung cancer [International Classification of Diseases #9 (ICD-9) 162] and cancers other than lung (ICD-9 140-239, excluding 162), and sex ratios were calculated. Mortality from lung cancer was well above national levels in all zones. For men, a weak gradient corresponding with proximity to industry at younger ages reversed at older ages. In women 0-64 years of age, stronger gradients in lung cancer mortality corresponded with proximity to industry across zones A, B, and C (SMR = 393, 251, 242, respectively). Overall rates in Teesside were higher than Sunderland rates for women aged 0-64 years (SMR = 287 vs. 185) and 65-74 years (SMR = 190 vs. 157). The association between raised lung cancer mortality and proximity to industry in women under 75 years of age could not be explained by smoking, occupation, socioeconomic factors, or artifact. Explanations for differences between men and women may include gender-specific occupational experiences and smoking patterns. Our judgment is that the observed gradient in women points to a role for industrial air pollution.

Cancer incidence and mortality around the Pan Britannica Industries pesticide factory, Waltham Abbey

OBJECTIVES

To examine the incidence and mortality of cancer near the Pan Britannica Industries factory, Waltham Abbey, after reports of a possible cluster of all cancers and brain cancer in the vicinity.

METHOD

Small area study of cancer incidence 1977-89, and mortality 1981-92, within a 7.5 km radius of the factory site. Postcoded cancer registrations and deaths in the study area were extracted from national data sets held by the Small Area Health Statistics Unit and compared with expected numbers computed by applying national rates stratified for age, sex, and deprivation to the local population (1981 and 1991 censuses). Observed/ expected (O/E) ratios were examined from 0-1 km and 0-7.5 km of the plant, and tests applied for a decline in relative risk with distance up to 7.5 km.

RESULTS

There were 12,859 incidence cancers (1977-89) from 0-7.5 km (O/E ratio 1.04; 95% confidence interval (95% CI) 1.02 to 1.06) and 385 from 0-1 km (O/E 1.10; 1.00 to 1.22). There was an excess of skin melanoma from 0-1 km based on 11 cases (O/E 2.13; 1.06 to 3.80), and an excess from 0-7.5 km of cancer of the lung, stomach and pancreas combined, and prostate (O/Es ranged from 1.09 to 1.13). Only the findings from lung cancer were suggestive of a decline in risk with distance, especially in the later period (1982-9). There were 9196 cancer deaths (1981-92) from 0-7.5 km (O/E 1.04; 95% CI 1.02 to 1.06) and 308 from 0-1 km (O/E 1.24; 1.11 to 1.39); and 25507 non-cancer deaths (O/E 1.02; 1.01 to 1.04) from 0-7.5 km and 745 (O/E 1.14; 1.06 to 1.22) from 0-1 km. There was evidence of a decline in mortality with distance for all cancers combined, lung cancer (P = 0.001 for each), and colorectal cancer (P < 0.05), and also for non-cancers (P = 0.001). Proportional mortality analyses suggested a decline in risk with distance for lung cancer (P = 0.003) but not for all cancers or the site specific cancers examined. There was no evidence of an excess in the incidence or mortality from brain cancer. For cancer mortality in the inner-most wards, the findings were, for the most part, well within the range of variation across the region as a whole.

CONCLUSIONS

The study provides limited and inconsistent evidence for a localised excess of cancer in the vicinity of the PBI plant. At present, further investigation does not seem warranted other than continued surveillance of mortality and cancer incidence in the locality.

Investigation of disease risks in small areas

The investigation of disease risks in small areas is complicated by many issues including data quality, the retrospective nature of the statistical testing, the problems of boundary definitions in time and space around a putative disease cluster, and the lack of generally accepted definitions of the key terminology. Routine data systems have revolutionised the initial investigation of disease risks near sources of environmental pollution, although problems of data analysis and interpretation remain. This is especially true of unmeasured socioeconomic confounding, which could generate apparent positive results near a pollution source.

Incidence of leukaemia and lymphoma in young people in the vicinity of the petrochemical plant at Baglan Bay, South Wales, 1974 to 1991

OBJECTIVE

To determine whether there was an increased incidence of leukaemias and lymphomas in young people aged less than 25 years in the locality of a petrochemical plant at Baglan Bay, South Wales.

METHODS

Geographical population based study to compare the observed and expected incidence of leukaemia and lymphoma with onset before the age of 25, in the years 1974 to 1991. The population was aged 0-24 years and lived within 1.5 and 3 km of the plant. The observed number of cases in various categories were compared with the expected numbers of cases calculated from the Welsh cancer registration rates.

RESULTS

Although the observed numbers were generally greater than would be expected, none of the comparisons showed significant excess of leukaemias or lymphomas for any period of years.

CONCLUSIONS

The study shows that the incidence of leukaemias and lymphomas in children and young people in the area around the BP Chemical site at Baglan Bay, South Wales, between the years 1974 and 1991 was not significantly greater than normal.