Female lung cancer mortality and sex ratios at birth near a petroleum refinery plant

Association between fine particulate air pollution and the risk of death from lung cancer in Taiwan

Airborne fine particulate matter (PM_2.5) has been classified as a Group I carcinogen leading to lung cancer in humans by the International Agency for Research on Cancer (IARC). In Taiwan, where there is a growing incidence of this disease, lung cancer is currently the leading cause of cancer-associated deaths in women and second leading cause of deaths in men. Because tobacco use is rare in Taiwan, especially amongst women, the high incidence of this type of cancer was suggested to be attributed to the other external contaminants, including airborne PM₂ pollution. In this ecologic study, a possible association between ambient air PM_2.5 exposure and likelihood of death attributed to lung cancer was examined in Taiwan in 66 municipalities. Annual PM_2.5 levels and age-standardized lung cancer mortality rates for male and female residents were calculated for years 2010 to 2019. Weighted-multiple regression was applied to analyze our data, adjusting for level of urbanization and physician density. For males, the adjusted risk ratios (RRs) for lung cancer mortality were 1.01 for municipalities with PM_2.5 levels 21.85-28.21 ug/m3 and 1.07 for municipalities with 28.22-31.23 ug/m3, compared to those with the lowest PM_2.5 levels. For females, these adjusted RRs were 0.99 and 1.06, respectively. Data demonstrated an association between chronic exposure to high levels of PM_2.5 and increased likelihood of death attributed to lung cancer for both men and women in Taiwan. Further studies are needed to explore the relationship between PM_2.5 air pollution exposure and risk of lung cancer histologic subtype.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Climate Justice and California's Methane Superemitters: Environmental Equity Assessment of Community Proximity and Exposure Intensity

Methane superemitters emit non-methane copollutants that are harmful to human health. Yet, no prior studies have assessed disparities in exposure to methane superemitters with respect to race/ethnicity, socioeconomic status, and civic engagement. To do so, we obtained the location, category (e.g., landfill, refinery), and emission rate of California methane superemitters from Next Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) flights conducted between 2016 and 2018. We identified block groups within 2 km of superemitters (exposed) and 5-10 km away (unexposed) using dasymetric mapping and assigned level of exposure among block groups within 2 km (measured via number of superemitter categories and total methane emissions). Analyses included 483 superemitters. The majority were dairy/manure (n = 213) and oil/gas production sites (n = 127). Results from fully adjusted logistic mixed models indicate environmental injustice in methane superemitter locations. For example, for every 10% increase in non-Hispanic Black residents, the odds of exposure increased by 10% (95% confidence interval (CI): 1.04, 1.17). We observed similar disparities for Hispanics and Native Americans but not with indicators of socioeconomic status. Among block groups located within 2 km, increasing proportions of non-White populations and lower voter turnout were associated with higher superemitter emission intensity. Previously unrecognized racial/ethnic disparities in exposure to California methane superemitters should be considered in policies to tackle methane emissions.

Methodological issues in descriptive environmental epidemiology. The example of study Sentieri

BACKGROUND

Descriptive epidemiology identifies associations between environmental exposures and health effects that require results from methodologically stronger studies before causation can be considered.

OBJECTIVE

To critically review the methodology and results of Sentieri, a descripitive study on residence in areas with one or more industrial source of pollution.

METHODS

We systematically reviewed the literature quoted by Sentieri for the selection of health effects of nine types of pollution sources of a-priori interest. We also reviewed and meta-analyzed the results of the first report of Sentieri, that analyzed mortality in 44 polluted sites (PS), and 17 causes of deaths during 1995-2002.

RESULTS

Among 159 study results quoted by Sentieri, 23.9 % were supportive of an association between residence near a pollution source and a health effect, 30.2 % were partially supportive, 10.7 % were not supportive, and 35.2 % were not relevant. Among 653 standardized mortality ratios for associations between PS-specific pollution sources and causes of death, 14.4% were significantly above 1.02, and 9.0% were significantly below 0.98. Among 48 meta-analysis, seven were significantly above 1.0, including five on exposure to asbestos.

CONCLUSIONS

Sentieri exemplifies the limitations of descriptive environmental epidemiology studies, in which most hypotheses have limited prior support, most results do not show associations, data on potential confounders and other sources of bias are not available. Such studies tend to replicate well-known associations and occasionally can identify critical situations requiring more investigation, but cannot be used to infer causality either in general or in specific circumstances.

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.

Air Pollution and Human Sperm Sex Ratio

The present study was designed to address the hypothesis that exposure to specific air pollutants may impact human sperm Y:X chromosome ratio. The study population consisted of 195 men who were attending an infertility clinic for diagnostic purposes and who had normal semen concentration of 15–300 mln/ml (WHO, 2010). Participants represented a subset of men in a multicenter parent study conducted in Poland to evaluate environmental factors and male fertility. Participants were interviewed and provided a semen sample. The Y:X ratio was assessed by fluorescent in situ hybridization (FISH). Air quality data were obtained from the AirBase database. In multivariate analysis the significant reduction was observed in the proportion of Y/X chromosome bearing sperm and exposure to particulate matter >10 μm in aerodynamic diameter PM₁₀ (p = .009) and particulate matter <10 μm in aerodynamic diameter PM_2.5 (p = .023). The observed effects of a lower Y:X sperm chromosome ratio among men exposed to air pollution support the evidence that the trend of declining sex ratio in several societies over past decades has been due to exposure to air pollution; however due to limited data on this issue, the obtained results should be confirmed in longitudinal studies.

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.

Contamination by oil crude extraction - Refinement and their effects on human health

The harmful effects of oil on various species of flora and fauna have been studied extensively; however, few studies have studied the effects of oil exposure on human health. The objective of this research was to collect information on the acute health effects and serious psychological symptoms of the possible consequences of such exposure to crude oil. Some studies focused on the composition of different chemicals used in the extraction process, and wastes generated proved to be highly harmful to human health. Thus, studies have shown that individuals who live near oil fields or wells - or who take part in activities of cleaning oil spills - have presented health conditions, such as irritation to the skin, eyes, mucous membranes, kidney damage, liver, reproductive, among others. In Ecuador, this reality is not different from other countries, and some studies have shown increased diseases related with oil crude and oil spills, like skin irritation, throat, liver, lung, infertility, and abortions, and it has been linked to childhood leukemia. Other studies suggest a direct relationship between DNA damage because of oil resulting in a genetic instability of the main enzymes of cellular metabolism as well as a relationship with some cancers, such as leukemia.

Systematic review of the association between oil and natural gas extraction processes and human reproduction

This systematic review identified 45 original published research articles related to oil and gas extraction activities and human reproductive endpoints. Reproductive outcomes were categorized as [1] birth outcomes associated with maternal exposure, [2] semen quality, fertility, and birth outcomes associated with adult paternal exposure, [3] reproductive cancers, and [4] disruption of human sex steroid hormone receptors. The results indicate there is moderate evidence for an increased risk of preterm birth, miscarriage, birth defects, decreased semen quality, and prostate cancer. The quality of the evidence is low and/or inadequate for stillbirth, sex ratio, and birth outcomes associated with paternal exposure, and testicular cancer, female reproductive tract cancers, and breast cancer, and the evidence is inconsistent for an increased risk of low birth weight; therefore, no conclusions can be drawn for these health effects. There is ample evidence for disruption of the estrogen, androgen, and progesterone receptors by oil and gas chemicals, which provides a mechanistic rationale for how exposure to oil and gas activities may increase the health risks we have outlined. The results from this systematic review suggest there is a negative impact on human reproduction from exposure to oil and gas activities. Many of the 45 studies reviewed identified potential human health effects. Most of these studies focused on conventional oil and gas activities. Few studies have been conducted to evaluate the impact of unconventional oil and gas operations on human health. The impact of unconventional oil and gas activities may be greater than that of conventional activity, given that unconventional activities employ many of the same approaches and use dozens of known endocrine-disrupting chemicals in hydraulic fracturing.

Exposure to widespread environmental endocrine disrupting chemicals and human sperm sex ratio

In recent years, a trend toward a declining proportion of male births has been noted in several, but not all, industrialized countries. The underlying reason for the drop in the sex ratio is unclear, but one theory states that widespread environmental endocrine disrupting chemicals affecting the male reproductive system in a negative manner could be part of the explanation. The present study was designed to investigate whether the urinary phthalate, pyrethroids and polycyclic aromatic hydrocarbons metabolites concentrations were associated with sperm Y:X ratio. The study population consisted of 194 men aged under 45 years of age who attended infertility clinic in Lodz, Poland for diagnostic purposes with normal semen concentration of 20-300 mln/ml or with slight oligozoospermia (semen concentration of 15-20 mln/ml) (WHO, 1999). The Y:X ratio was assessed by fluorescent in situ hybridization. Urinary concentrations of 1-hydroxypyrene were measured by high performance liquid chromatography, phthalate metabolites were analyzed using a procedure based on the LC-MS/MS methods and metabolites of synthetic pyrethroids were assessed by gas chromatography ion-tap mass spectrometry method. After adjustment for potential confounders (past diseases, age, abstinence, smoking, alcohol consumption, sperm concentration, motility, morphology) 5OH MEHP, CDCCA to TDCCA and 1-OHP was negatively related to Y:X sperm chromosome ratio (p = 0.033, p < 0.001, p = 0.047 respectively). As this is the first study to elucidate the association between the level of metabolites of widespread environmental endocrine disrupting chemicals (phthalates, synthetic pyrethroids, polycyclic aromatic hydrocarbons) on sex chromosome ratio in sperm therefore, these findings require further replication in other populations.

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.

Parity and risk of death from lung cancer among a cohort of premenopausal parous women in Taiwan

Background

We examined the association between parity and risk of lung cancer.

Methods

The study cohort consisted of all women with a record of a first singleton birth in the Taiwanese Birth Register between 1978 and 1987. We tracked each woman from the time of their first childbirth to 31 December 2009. Follow-up was terminated when the mother died, when she reached age 50 years, or on 31 December 2009, whichever occurred first. The vital status of mothers was ascertained by linking records with the computerized mortality database. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) for death from lung cancer associated with parity.

Results

There were 1375 lung cancer deaths during 32 243 637.08 person-years of follow-up. The mortality rate of lung cancer was 4.26 cases per 100 000 person-years. As compared with women who had given birth to only 1 child, the adjusted HR was 1.13 (95% CI, 0.94–1.35) for women who had 2 children, 1.10 (0.91–1.33) for those who had 3 children, and 1.22 (0.96–1.54) for those who had 4 or more children.

Conclusions

The findings suggest that premenopausal women of higher parity tended to have an increased risk of lung cancer, although the trend was not statistically significant.

Determination of total petroleum hydrocarbons (TPH) in agricultural soils near a petrochemical complex in Guangzhou, China

The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected from surface layers (0-20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou, China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg( - 1), with the average of 2,676.6 mg kg( - 1). Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would not mean human health risks near the petrochemical complex.

Size distribution and chemical composition of metalliferous stack emissions in the San Roque petroleum refinery complex, southern Spain

We demonstrate that there is great variation in the size range and chemical composition of metalliferous particulate matter (PM) present within petrochemical complex chimney stacks. Cascade impactor PM samples from seven size ranges (17, 14, 5, 2.5, 1.3, 0.67, and 0.33 μm) were collected from inside stacks within the San Roque complex which includes the largest oil refinery in Spain. SEM analysis demonstrates the PM to be mostly carbonaceous and aluminous fly ash and abundant fine metalliferous particles. The metals with the most extreme concentrations averaged over all size ranges were Ni (up to 3295 μg m(-3)), Cr (962 μg m(-3)), V (638 μg m(-3)), Zn (225 μg m(-3)), Mo (91 μg m(-3)), La (865 μg m(-3)), and Co (94 μg m(-3)). Most metal PM are strongly concentrated into the finest fraction (<0.33 μm), although emissions from some processes, such as purified terephthallic acid (PTA) production, show coarser size ranges. The fluid catalytic cracking stack shows high concentrations of La (>200 μg m(-3) in PM(0.67-1.3)), Cr and Ni in a relatively coarse PM size range (0.7-14 μm). Our unique database, directly sampled from chimney stacks, confirms that oil refinery complexes such as San Roque are a potent source of a variety of fine, deeply inhalable metalliferous atmospheric PM emissions.

Can environmental or occupational hazards alter the sex ratio at birth? A systematic review

More than 100 studies have examined whether environmental or occupational exposures of parents affect the sex ratio of their offspring at birth. For this review, we searched Medline and Web of Science using the terms ‘sex ratio at birth’ and ‘sex ratio and exposure’ for all dates, and reviewed bibliographies of relevant studies to find additional articles. This review focuses on exposures that have been the subject of at least four studies including polychlorinated biphenyls (PCBs), dioxins, pesticides, lead and other metals, radiation, boron, and g-forces. For paternal exposures, only dioxins and PCBs were consistently associated with sex ratios higher or lower than the expected 1.06. Dioxins were associated with a decreased proportion of male births, whereas PCBs were associated with an increased proportion of male births. There was limited evidence for a decrease in the proportion of male births after paternal exposure to DBCP, lead, methylmercury, non-ionizing radiation, ionizing radiation treatment for childhood cancer, boron, or g-forces. Few studies have found higher or lower sex ratios associated with maternal exposures. Studies in humans and animals have found a reduction in the number of male births associated with lower male fertility, but the mechanism by which environmental hazards might change the sex ratio has not yet been established.

Spatial analysis of air pollution and cancer incidence rates in Haifa Bay, Israel

The Israel National Cancer Registry reported in 2001 that cancer incidence rates in the Haifa area are roughly 20% above the national average. Since Haifa has been the major industrial center in Israel since 1930, concern has been raised that the elevated cancer rates may be associated with historically high air pollution levels. This work tests whether persistent spatial patterns of metrics of chronic exposure to air pollutants are associated with the observed patterns of cancer incidence rates. Risk metrics of chronic exposure to PM(10), emitted both by industry and traffic, and to SO(2), a marker of industrial emissions, was developed. Ward-based maps of standardized incidence rates of three prevalent cancers: Non-Hodgkin's lymphoma, lung cancer and bladder cancer were also produced. Global clustering tests were employed to filter out those cancers that show sufficiently random spatial distribution to have a nil probability of being related to the spatial non-random risk maps. A Bayesian method was employed to assess possible associations between the morbidity and risk patterns, accounting for the ward-based socioeconomic status ranking. Lung cancer in males and bladder cancer in both genders showed non-random spatial patterns. No significant associations between the SO(2)-based risk maps and any of the cancers were found. Lung cancer in males was found to be associated with PM(10), with the relative risk associated with an increase of 1 microg/m(3) of PM(10) being 12%. Special consideration of wards with expected rates <1 improved the results by decreasing the variance of the spatially correlated residual log-relative risk.

Traffic air pollution and lung cancer in females in Taiwan: petrol station density as an indicator of disease development

To investigate the relationship between traffic air pollution exposure and development of lung cancer in females, studies were conducted using a matched cancer case-control model into deaths that occurred in Taiwan from 1997 through 2006. Data on all eligible lung cancer deaths in females were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of women who died from causes other than neoplasms or diseases that were associated with respiratory problems. The controls were pair matched to the cancer cases by year of birth and year of death. Each matched control was selected randomly from the set of possible controls for each case. Data on the number of petrol stations in study municipalities were collected from the two major petroleum supply companies, Chinese Petroleum Corporation (CPC) and Formosa Petrochemical Corporation (FPCC). The petrol station density (per square kilometer; PSD) for study municipalities was used as an indicator of a subject's exposure to benzene and other hydrocarbons present in ambient evaporative losses of petrol or to air emissions from motor vehicles. The subjects were divided into tertiles according to PSD in their residential municipality. The results showed that there was a significant exposure-response relationship between PSD and risk of lung cancer in females after controlling for possible confounders. The findings of this study warrant further investigation of the role of traffic air pollution exposure in the etiology of lung cancer.

Ambient exposure to criteria air pollutants and female lung cancer in Taiwan

To investigate the relationship between air pollution and female lung cancer, the authors conducted a matched case-control study using female deaths that occurred in Taiwan from 1995 through 2005. Data on all eligible female lung cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of women who died from causes other than cancer or diseases 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. Classification of exposure to municipality air pollution was based on the measured levels of nitrogen dioxide and carbon monoxide. The results of the present study show that there is a significant positive association between the levels of air pollution and female lung cancer mortality. The adjusted odds ratios (95% confidence interval) were 1.24 (1.03-1.50) for the group with medium air pollution level and 1.46 (1.18-1.81) for the group with high air pollution level when compared to the group with the low air pollution level. Trend analyses showed statistically significant trend in risk of female lung cancer with increasing air pollution level. The findings of this study warrant further investigation of the role of air pollutants in the etiology of lung cancer.

Does arsenic exposure increase the risk of development of peripheral vascular diseases in humans?

Arsenic has been well documented as a major risk factor in the development of blackfoot disease (BFD), a unique peripheral vascular disease (PVD) endemic to the southwestern coast of Taiwan, where residents imbibed artesian well water containing excessive amounts of arsenic for more than 50 yr. Long-term arsenic exposure was also reported to be associated with mortality attributed to PVD. A tap-water supply system was implemented in the early 1960s in the BFD endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to examine whether mortality attributed to PVD decreased after the consumption of artesian well water containing high concentrations of arsenic ceased and, if so, when the reduction occurred. Standardized mortality ratios (SMRs) for PVD were calculated for the BFD endemic area for the years 1971-2003. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. Data showed that mortality due to PVD declined gradually for approximately 25 to 27 yr following cessation of consumption of this arsenic artesian well water. Based on the reversibility criterion, the association between arsenic exposure and PVD-attributed mortality is likely to be causal.

Outdoor air pollution and female lung cancer in Taiwan

To investigate the relationship between air pollution and female lung cancer, the authors conducted a matched case-control study using female deaths that occurred in Taiwan from 1994 through 2003. Data on all eligible female lung cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of women who died from causes other than cancer or diseases 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. A municipality-based aggregate index of long-term exposure to air pollution was created by dividing the annual average of the measured values for each pollutant by the National Ambient Air Quality Standard for that pollutant. The ratios for each pollutant were scaled to a 100-point scale and then averaged together to generate an index value representing the net burden of these pollutants, with each weighted equally. The subjects were divided into tertiles according to the levels of the index just described. Women who lived in the group of municipalities with highest levels of air pollution exposure index were at a statistically significant increased lung cancer risk compared to the group living in municipalities with the lowest air pollution exposure index after controlling for possible confounders (OR = 1.28, 95% CI = 1.02-1.61). The findings of this study warrant further investigation of the role of air pollutants in the etiology of lung cancer.

Reduction in kidney cancer mortality following installation of a tap water supply system in an arsenic-endemic area of Taiwan

Arsenic is the major risk factor for blackfoot disease, a peripheral vascular disease that has been endemic to the southwest coast of Taiwan for more than 50 yr because of the consumption of local artesian well water containing high levels of arsenic. Long-term arsenic exposure has been associated with kidney cancer mortality in a dose-response relationship. In the early 1960s, a tap water supply system was implemented in the blackfoot-endemic areas. After the mid-1970s, artesian well water was no longer used for drinking or cooking in the region. The authors examined whether kidney cancer mortality decreased after the elimination of arsenic exposure from artesian well water. Standardized mortality ratios for kidney cancer were calculated for the blackfoot-endemic area for the years 1971-2000. Study results showed that mortality from kidney cancer declined gradually during this time; therefore, the association of arsenic exposure with kidney cancer mortality was likely causal.

Declining sex ratio in a first nation community

Members of the Aamjiwnaang First Nation community near Sarnia, Ontario, Canada, voiced concerns that there appeared to be fewer male children in their community in recent years. In response to these concerns, we assessed the sex ratio (proportion of male births) of the Aamjiwnaang First Nation over the period 1984-2003 as part of a community-based participatory research project. The trend in the proportion of male live births of the Aamjiwnaang First Nation has been declining continuously from the early 1990s to 2003, from an apparently stable sex ratio prior to this time. The proportion of male births (m) showed a statistically significant decline over the most recent 10-year period (1994-2003) (m = 0.412, p = 0.008) with the most pronounced decrease observed during the most recent 5 years (1999-2003) (m = 0.348, p = 0.006). Numerous factors have been associated with a decrease in the proportion of male births in a population, including a number of environmental and occupational chemical exposures. This community is located within the Great Lakes St. Clair River Area of Concern and is situated immediately adjacent to several large petrochemical, polymer, and chemical industrial plants. Although there are several potential factors that could be contributing to the observed decrease in sex ratio of the Aamjiwnaang First Nation, the close proximity of this community to a large aggregation of industries and potential exposures to compounds that may influence sex ratios warrants further assessment into the types of chemical exposures for this population. A community health survey is currently under way to gather more information about the health of the Aamjiwnaang community and to provide additional information about the factors that could be contributing to the observed decrease in the proportion of male births in recent years.

Does arsenic exposure increase the risk for liver cancer?

Arsenic has been well documented as the major risk factor for development of blackfoot disease (BFD), a unique peripheral vascular disease that was once endemic to the southwestern coast of Taiwan, where residents imbibed artesian well water containing high concentrations of arsenic for more than 50yr. Long-term arsenic exposure has also been reported to be associated with increased incidence of liver cancer in a dose-responsive manner. A tap-water supply system was implemented in the early 1960s in the BFD endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to examine whether liver cancer mortality rates were altered after the consumption of high-arsenic artesian well water ceased and, if so, when the reduction occurred. Standardized mortality ratios (SMRs) for liver cancer were calculated for the BFD endemic area for the years 1971-2000. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. The study results show that mortality from liver cancer in females declined starting 9yr after the cessation of consumption of high-arsenic artesian well water. However, data show fluctuations in male liver cancer mortality rates. Based on the reversibility criterion, the association between arsenic exposure and liver cancer mortality is likely to be causal for females but not in males.

Ischemic heart disease mortality reduction in an arseniasis-endemic area in southwestern Taiwan after a switch in the tap-water supply system

Arsenic has been identified as a major contributing risk factor for development of blackfoot disease (BFD), a unique peripheral vascular disease that was endemic to the southwestern coast of Taiwan, where residents imbibed artesian well water continuing high amounts of arsenic for more than 50 yr. Chronic arsenic exposure was found to be associated with ischemic heart disease (CHD) in a dose-dependent manner. A tap-water supply system was implemented in the early 1960s in the BFD-endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to examine whether CHD-related mortality decreased after consumption of high-arsenic-containing artesian well water ceased and, if so, when the reduction occurred. Standardized mortality ratios (SMRs) for CHD were calculated for the BFD endemic area for the years 1971-2000. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. Data show that mortality attributed to CHD declined gradually for approximately 17 to 20 yr following cessation of consumption of high-arsenic artesian well water. Based on the reversibility criterion, the association between arsenic exposure an1rd CHD-related mortality is likely to be causal.

Increased risk of preterm delivery among people living near the three oil refineries in Taiwan

The petrochemical and petroleum industries are two of the main sources of industrial air pollution in Taiwan. Data used in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to oil refinery plants. The prevalence of delivery of preterm birth infants was significantly higher in mothers living near the oil refinery plants than in control mothers in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.14 (95% CI=1.01-1.28) for delivery of preterm infants for mothers living near oil refinery plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancies.

Evidence for Increased Risks of Preterm Delivery in a Population Residing near a Freeway in Taiwan

Traffic emissions are a major source of air pollution in urban areas. The results of recent studies have suggested that air pollution may be related to adverse pregnancy outcomes such as low birth weight and preterm delivery. The authors investigated the association between traffic-related air pollution and preterm deliveries. The study group included all first-parity singleton live births that occurred during 1992-1997 to women who lived in a zone along the Zhong-Shan Freeway in Taiwan (N = 6,251). The zone was defined as areas 1,500-m wide on either side of the freeway; it was located in the San-Ming, Nan-Tzu, Chienchen, and Linya wards-all of which are residential areas in East Kaohsiung. The prevalence of deliveries of preterm birth infants was significantly higher among mothers who lived within 500 m of the freeway than among mothers who resided 500-1,500 m from the freeway. In their analysis, the authors controlled for several confounders (e.g., maternal age, season, marital status, maternal education, infant gender). The adjusted odds ratio was 1.30 (95% confidence interval = 1.03, 1.65) for delivery of preterm infants born to mothers who lived within 500 m of the freeway. Such data provide additional support for the hypothesis that air pollution can affect the outcome of pregnancy.

Increased risk of preterm delivery in areas with cancer mortality problems from petrochemical complexes

The petrochemical and petroleum industries are the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to petrochemical industrial complexes. The prevalence of delivery of preterm birth infants was significantly higher in mothers living near petrochemical industrial complexes than in control mothers living elsewhere in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.18 (95% CI=1.04-1.34) for delivery of preterm infants in the petrochemically polluted region. The data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.

Increased risk of preterm delivery in areas with air pollution from a petroleum refinery plant in Taiwan

The petrochemical and petroleum industries are among the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to a petroleum refinery plant. The prevalence of delivery of preterm birth infants was significantly higher in mothers living in a petroleum refinery area compared to controls in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.41 (95% CI = 1.08-1.82) for delivery of preterm infants in the polluted region. Data support the view that air pollution can affect the outcome of pregnancy.