Study: Traffic-related air pollution associated with changes in right ventricular structure and function

The following article was originally published on medicalxpress.com. 

Exposure to high levels of traffic-related air pollution is associated with changes in the right ventricle of the heart that may contribute to the known connection between air pollution exposure and heart disease, according to a new study.

“Although the link between traffic-related air pollution and left ventricular hypertrophy, heart failure, and cardiovascular death is established, the effects of traffic-related air pollution on the right ventricle have not been well studied,” said lead author Peter Leary, MD, MS, of the University of Washington Medical Center in Seattle. “Using exposure to nitrogen dioxide as a surrogate for exposure to traffic-related air pollution, we were able to demonstrate for the first time that higher levels of exposure were associated with greater right ventricular mass and larger right ventricular end-diastolic volume. Greater right ventricular mass is also associated with increased risk for heart failure and cardiovascular death.”

The findings were published online ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

The study involved 3,896 participants who were free of clinical cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis and who underwent cardiac magnetic resonance imaging (MRI). Using estimated exposure to outdoor oxides of nitrogen at the homes of participants over the year preceding MRI, the authors found that increased exposure to nitrogen dioxide was associated with an approximately 1.0 g (5 percent) increase in right ventricular mass and a 4.1 mL (3%) increase in right ventricular end-diastolic volume.

These relationships remained after accounting for differences among participants in cardiovascular risk factors, left ventricular mass and volume, markers of inflammation, lung disease and socioeconomic status.

The authors note that this type of study can be limited in several ways. Specifically, estimates of air pollution exposure are not perfect and it remains possible that something related to air pollution, but not air pollution itself (known as confounding), was responsible for the association. For these reasons and others, this study cannot prove that traffic-related air pollution causes changes in the right heart, but does strongly suggest the relationship.

“The morphologic changes in the right ventricle of the heart that we found with increased exposure to nitrogen dioxide add to the body of evidence supporting a connection between traffic-related air pollution and cardiovascular disease,” said Dr, Leary. “The many adverse effects of air pollution on human health support continued efforts to reduce this burden.”

Explore further: Ozone linked to heart disease deaths

Journal reference: American Journal of Respiratory and Critical Care Medicine  

Provided by American Thoracic Society 

Soot is even worse for the climate than was previously thought

Jan 19th 2013 |From the print edition

SOOT—also known as black carbon—heats up the atmosphere because it absorbs sunlight. Black things do. That is basic physics. But for years the institutions that focus on climate policy have played down the role of pollutants such as black carbon that stay in the atmosphere for a short time, and concentrated on carbon dioxide, which, once generated, tends to remain there. That may soon change.

On January 15th, the fifth day that smog-darkened Beijing’s air-quality index was registering “hazardous” (see article), the most comprehensive study of black carbon yet conducted was published in the Journal of Geophysical Research: Atmospheres. It concluded that the stuff was the second-most-damaging greenhouse agent after CO₂ and about twice as bad for the climate as had been thought until now. The implications are profound.

This study, a four-year affair conducted under the auspices of the International Global Atmospheric Chemistry Project, an umbrella group for research into such matters, is based on a lot more information about soot than was previously available, and a better understanding of how it affects the climate. It found that the black carbon around at the moment has a warming effect of about 1.1 watts per square metre of the Earth’s surface (W/m²). This is greater than that of methane and second only to the 1.7W/m² of carbon dioxide. An earlier estimate by the United Nations Environment Programme (UNEP) put the black-carbon effect at only 0.3-0.6W/m². The higher the figure, the worse the warming.

Black carbon is especially damaging to frozen regions, because when soot falls on snow and ice it increases the amount of light and heat they absorb. The new assessment may therefore help explain why the Arctic has been melting faster than anyone had expected. The study argues that warming is likely to be especially marked in the high latitudes of the northern hemisphere—northern Canada, Alaska, northern Europe and Siberia. It also gives a warning that black carbon, by changing regional precipitation patterns, may affect Asian monsoons.

Sweep it away

The biggest impact of soot, though, is not on the climate but on health—through lung and other diseases. The UNEP study reckoned that controlling emissions of black carbon could save 2.4m lives a year, regardless of any effects on the climate.

It might seem that the new study is one more item of bad environmental news. Not so. It should be easier to deal with black carbon than with carbon dioxide. Whereas CO₂ is long-lasting and an inevitable by-product of burning fossil fuels, soot drops out of the atmosphere within weeks. Stop putting it there and it will rapidly go away—a potentially easy win.

That win is made easier still by the fact that about 70% of emissions in Europe and the Americas come from diesel engines. Better exhausts, to trap carbon particles before they are emitted, and the scrapping of old, highly polluting vehicles could make an immediate impact. In other countries the problem is more often inefficient stoves and dirty fuel—again, things that are easy to deal with, at least in principle.

Dealing with them is also cheaper than cutting CO₂ emissions and does not need global agreement, because the local benefits would be the main point, so no one could free-ride on the emission-cutting efforts of others. Instead, the good of the climate would be free-riding on local self-interest. Piers Forster of Leeds University, in England, one of the study’s authors, argues that if people did everything they could to reduce black-carbon emissions, it would strip half a degree of temperature rise out of the process of global warming—or, to put it another way, would give politicians two extra decades to tackle the less tractable question of what to do about CO₂.

From the print edition: Science and technology

Air pollution linked to pregnancy condition

BY JULIET RYAN

Contributing Reporter, Yale Daily News

 

Pregnant women are warned to stay away from a lot of things: raw fish, alcohol, drugs — and now, traffic.

A recent study conducted at the Telethon Institute for Child Health Research in Perth, Australia, showed that increased exposure to traffic-related air pollution is associated with an up to 30 percent increase in the risk of developing preeclampsia, a serious complication in late-term pregnant women. Preeclampsia develops when blood flow is diminished during the placentation process, causing high blood pressure, swelling, pain, nausea and even seizures in the mother. Currently, the only treatment for the condition is to deliver the baby, making it the cause of many preterm births.

The researchers measured nitrogen dioxide levels at a total of 22 sites around Perth, and then used a land use regression model based on the time of year and the traffic volume to predict past levels of nitrogen dioxide in those locations. The study also collected data — including hospital and birth records — from 23,452 women who had given birth between 2001 and 2006.

Out of these 23,452 women, 4 percent developed preeclampsia, said Gavin Pereira, a postdoctoral associate at the Yale School of Medicine and lead author of the study. Those who lived closer to areas with a larger volume of traffic, such as highways, were 30 percent more likely to develop preeclampsia. Residents of congested areas who were already at a higher risk for preeclampsia, such as diabetic women, were 53 percent more likely to suffer from it than healthy women in uncongested areas.

Pereira cautioned against concluding that air pollution cased preeclampsia, the exact causes of which are remain mysterious.“This study was never going to say that preeclampsia is caused by air pollution,” Pereira said. “It’s likely that there are multiple causes and risk factors [such as obesity, and diabetes].”

Elizabeth Triche, a perinatal and environmental epidemiologist at Brown University and an expert on preeclampsia, said air pollution was almost certainly not the cause of preeclampsia but could serve as a trigger for the disorder. She said that areas with high rates of air pollution often have lower oxygen levels, which could send the mother into a hypoxic state that leaves her more vulnerable to developing preeclampsia. This effect could be particularly strong during late term pregnancy, when fast fetus growth places greater demands on its mother’s body, Triche added.

While pregnant women should stay away from prolonged exposure to traffic-related air pollution to reduce risk, the burden should not fall solely on them, Pereira said.

“The real question is how should society change,” he said. “Because the study was population-based, there should be a population-wide response: there should be a minimum distance from highways at which housing departments and schools should be built.”

Pereira said that because many researchers are working closely with government agencies such as the Environmental Protection Agency and the National Institutes of Health, societal change might be possible.

The registry data is inherently limited, said Michael Paidas, professor of obstetrics, gynecology and reproductive sciences at the Yale School of Medicine, who was not involved in the study. Incorrect diagnoses of past patients could skew the study’s results, he said.

“[There were] lots of extrapolations, but they still all seem very reasonable,” Paidas said.

Paidas also lauded the study’s efforts to address socioeconomic statuses and pre-existing conditions as well as pure medical outcomes. In hopes of better understanding preeclampsia and perhaps finding a cure, he is currently participating in a study on a cohort of pregnant Danish women.

Pereira acknowledged that the study’s methodology was not perfect. For example, he said, women could have moved locations during their pregnancy, modifying their apparent exposure to traffic-related air pollution in the hospital’s birth registry.Periera has recently started a study at Yale looking at the association between traffic related air pollution and preterm births.

Urban air pollution raises Vitamin D Deficiency risk in newborns

 

Washington, September 16 (ANI): Gestational exposure to ambient urban air pollution, especially during late pregnancy, may contribute to lower vitamin D levels in offspring, a new study has revealed.

According to study authors, this could affect the child’s risk of developing diseases later in life.

Recent data has demonstrated that maternal vitamin D deficiency during pregnancy may have an influence on the development of asthma and allergic diseases in offspring.

A number of factors may influence vitamin D supply in women. Exposure to high levels of air pollution has been suggested as a contributor to vitamin D deficiency in adults and children.

“We investigated the associations between gestational exposure to urban air pollutants and vitamin D cord blood serum level,” Nour Baiz, the study leader from the Intitut National de la Sante et de la Recherche Medicale (INSERM) in Paris, France, said.

“Our findings show for the first time, that exposure to ambient air pollution comparable to current World Health Organization standards might contribute to vitamin D deficiency in newborns,” Baiz said.

In this study, researchers investigated the associations between gestational exposure to urban air pollutants and 25-hydroxyvitamin D cord blood serum level in 375 mother-child pairs.

Maternal exposure to urban levels of nitrogen dioxide and particulate matter less than 10 micro meters during the whole pregnancy was a strong predictor of low vitamin D status in newborns.

The association between gestational exposure to air pollutants and vitamin D deficiency in newborns was strongest for third-trimester exposures.

The study has been accepted for publication by the Journal of Clinical Endocrinology and Metabolism (JCEM). (ANI)

Air pollution linked to stillbirth risk

by Joseph Brownstein  – MyHealthNewsDaily (This article originally appeared here.)

Air pollution has been linked to a number of breathing problems, mainly in developing countries, and now a new preliminary study looking at pollution levels in New Jersey has found an increased risk of stillbirths among women exposed to specific pollutants.

“We found that different pollutants are harmful in different trimesters of pregnancy,” said Dr. Ambarina Faiz, an instructor at Robert Wood Johnson Medical School. For example, exposure to a high level of nitrogen dioxide was particularly harmful during the first trimester, she said.

The study was published online July 18 in the American Journal of Epidemiology.

In their study, researchers used statewide birth data from 1998 through 2004. They compared live births with stillbirths, looking at mothers who lived within 10 kilometers (a little over 6 miles) of New Jersey’s 25 pollutant-monitoring stations.

They also gathered data from those stations: 11 stations monitored nitrogen dioxide, 16 monitored sulfur dioxide and 16 monitored carbon monoxide.

Researchers compared the pollutant concentrations during a woman’s three trimesters of pregnancy, and took into account factors known to affect stillbirth risk, including the mother’s age, smoking, ethnicity and prenatal care.

 

What they found

Several trends emerged from the data. In general, stillbirths were rare, with fewer than 1,000 among the hundreds of thousands of births in any region where the researchers measured pollutants. For example, among the more than 207,000 women whose carbon monoxide exposure was estimated as being elevated during their first trimester, there were about 800 stillbirths. (Researchers defined a stillbirth as the death of a fetus after the 20th week of pregnancy.)

The stillbirth risk was elevated for mothers exposed to pollutants during certain times of pregnancy.

Results showed that throughout pregnancy, for every 10 parts per billion increase in nitrogen dioxide levels, risk of stillbirth increased 27 percent. For every increase of 10-ppb in the pollutant during the first trimester, the stillbirth risk increased by 16 percent.

For sulfur dioxide, the stillbirth risk increased 13 percent with every 3-ppb increase in the first trimester, and 26 percent for every 3-ppb increase in the third trimester.

Carbon monoxide was associated with a 14 percent increase in stillbirth risk in the second and third trimesters for every 400-ppb increase in concentration.

It remains unclear whether reducing pollution alone could prevent stillbirths, or how many could be avoided, Faiz said. “But it is a risk factor, and it should be looked at with more accurate [measurement] of exposure,” she said.

Air pollution vs. smoking

The study was not as strong as it would have been had researchers been able to measure each woman’s level of pollution exposure. But in following up on the few studies that have looked at air pollution and maternal health, it does contribute to a trend, experts said.

“Most air pollution studies are done to evaluate the health effects related to the respiratory system, [such as] asthma or COPD,” said Dr. Youcheng Liu, an associate professor of environmental and occupational health at the University of North Texas Health Science Center. “Relatively few studies…are related to reproductive health.”

One problem is that it’s still unclear how pollution might have such an effect. While pollutants present an obvious risk to the lungs, “Why to the fetus, across the placenta? In terms of mechanism, it still needs an explanation,” Liu said.

Because of the way data were collected, the study gives information about the region where women live, but not necessarily their exact exposure, giving an extra variable that can skew results.

“People, during pregnancy, move around,” Liu said. Among those who may not have traveled great distances, “even at home, the [exposure levels] can be affected by whether you open the window or not, whether you do cooking or not.”

The most obvious hazard for mothers wanting to avoid air pollution exposure is smoking, the dangers of which far exceed those of the air pollutants looked at in the study, he said.

Liu added that concerned expectant mothers might monitor levels of smog, and run errands or travel outside during periods where smog or other pollution levels are expected to be lower.

But it remains clear that further work needs to be done to understand just how much extra caution about air pollution could be needed.

“It increases the risk, but how much and to what extent, I’m not sure about that,” Faiz said.

Study Shows Allergy and Asthma Linked to the Air Students Breathe

By Kirsty Oswald, MedWire Reporter

The original post can be found here.

Poor air quality inside classrooms could play a role in the development of asthma and allergies in children, the results of a French study show.

Researchers found that pupils exposed to high levels of fine particles with aerodynamic diameter of 2.5 µm or less (PM_2.5), nitrogen dioxide (NO₂), and acrolein were more likely to have had asthma in the previous year than those exposed to low levels. Furthermore, high classroom levels of formaldehyde were associated with an increased probability for rhinoconjunctivitis.

“The alarming consequence of poor air quality in classrooms was a deterioration of respiratory health,” say Isabella Annesi-Maesano (Université Pierre et Marie Curie, Paris, France) and colleagues.

The study included 6590 children aged 9‑10 years enrolled at 108 schools across six French cities. The researchers assessed the children using a questionnaire that their parents completed, a skin prick test for 10 common allergens, and a run test for exercise-induced asthma. Concentrations of air pollutants were taken from their classrooms, in most cases during the same week.

The authors, reporting in Thorax, found that nearly a third of schoolchildren were exposed to levels of PM_2.5 and NO₂ at concentrations greater than the upper thresholds proposed by the World Health Organization.

Overall, 6.9% of pupils had had asthma in the previous year, and 11.8% had had rhinoconjunctivitis.

Pupils exposed to high levels of PM_2.5 had a 21% increase in the odds for having asthma in the past year. Similarly, the probability increased by 22% amongst those exposed to high levels of acrolein, compared with low exposures. When just allergicasthma was considered, high NO₂ exposure also significantly increased the probability, by 40% compared with low exposure to NO₂.

High formaldehyde exposure was also associated with an increased probability of rhinoconjunctivitis, where the odds for the allergy were 19% greater than with low levels of exposure.

The authors say that their study helps to fill a gap in data about the effects of indoor air pollution on respiratory health, particularly in children.

“This lack of data is in spite of the fact that there is growing concern about the school environment, where children spend up to eight hours a day,” they say.

They also recommend further research in younger children to elucidate the role of indoor air pollutants in the development of asthma and allergies.

Ozone Exposure and Your Heart

By Jing Zhang, a student services contractor working on the Science Communications Team in EPA’s the Office of Research and Development.

I couldn’t imagine living in a world where buildings are filled with thick cigarette smoke, but smokeless buildings haven’t always been the norm. Many things today, such as washing hands to avoid spreading germs, were previously not the norm and are the result of scientific findings uncovered years ago.

EPA researchers and scientists are constantly conducting studies to make important advances in improving human health and the environment. One such EPA study was recently published in the American Heart Association journal Circulation. (Read the press release.)

According to the study, breathing in ozone can be harmful to both your lungs and your heart.

For years, air pollutants, including ozone, have been known to harm the lungs. The EPA ozone study shows that breathing in ozone can cause inflammation of the vascular system, a change in heart rate variability, and a reduction in the ability of blood clots to dissolve, which are risk factors for heart disease.  The study also confirmed the ability of ozone to impact lung inflammation and function.

It amazes me how a seemingly simple molecule composed of three tiny oxygen atoms can impact lung and heart health! Where does this tiny yet harmful air pollutant come from?

As it turns out, ozone is in two areas of the earth’s atmosphere. Ozone exists naturally in the upper regions of the atmosphere, where it protects the earth from the sun’s harmful ultraviolet rays. Ozone found at the ground level is created from the mixture of nitrogen oxides (NO_x), volatile organic compounds (VOC), and sunlight. The NO_x and VOC emissions come from sources including industrial facilities, electric utilities, and vehicle exhausts.

Because sunlight is a key factor in creating ground-level ozone, sunny days can create unhealthy levels of ozone in urban areas. Some people, including children, older adults, and those with preexisting heart or lung conditions, are at greatest risk from exposure to ozone.

In order to protect your health, use EPA’s Air Quality Index, which forecasts air quality on a daily basis, and minimize time spent outside on high ozone days.

The recently-released EPA study paves the way for further research on the health effects of exposure to ozone. With more discoveries, the impacts of ozone on health may become as widely known as the impacts of cigarette smoke on health. In the meantime, EPA scientists are continuously conducting cutting-edge research to protect your heart from outdoor air pollution and environmental effects.

To learn more about EPA air research, vistit: www.epa.gov/airscience

More Evidence Showing Prenatal Exposure to Pollution Impacts Childhood Lung Growth

ScienceDaily (May 20, 2012) — The link between prenatal exposure to air pollution and childhood lung growth and respiratory ailments has been established by several studies in recent years, and now a new study suggests that these prenatal exposures can be especially serious for children with asthma.

The study will be presented at the ATS 2012 International Conference in San Francisco. “In this study, we found that prenatal exposures to airborne particles and the pollutant nitrogen dioxide adversely affect pulmonary function growth among asthmatic children between 6 and 15 years of age,” said study lead author Amy Padula, PhD, post-doctoral fellow at the University of California, Berkeley. “This analysis adds to the evidence that maternal exposure to ambient air pollutants can have persistent effects on lung function development in children with asthma.”

The study was conducted as part of the Fresno Asthmatic Children’s Environment Study (FACES) — Lifetime Exposure initiative, which examines the influence of prenatal exposure to a number of ambient air pollutants on the growth of lung function during childhood and teen years in a high pollution area.

For this analysis, the researchers included repeated evaluations of 162 asthmatic children between the ages of 6 and 15 and their mothers. To determine prenatal exposure levels to pollution, the mothers’ residences during pregnancy were geocoded and pollutant concentrations were obtained from the Aerometric Information Retrieval System supported by the U.S. Environmental Protection Agency (EPA).Monthly average pollutant concentrations were assigned from 24-hour averages obtained at a central site monitor and summaries of the entire pregnancy and each trimester were calculated. The researchers looked at several pollutants, including carbon monoxide, nitrogen dioxide, ozone and particulate matter.

To calculate lung function growth, which is determined primarily by changes in lung capacity as a child grows, the researchers used spirometry, a technique which measures the volume and speed of air as it is exhaled from the lungs. For this study, multiple lung function tests were performed and significant changes were noted in four measurements: the FVC, or forced vital capacity, which reflects the volume of air that can be blown out after fully inhaling; the FEV1, or forced expiratory volume in 1 second, which is the volume of air that can forcibly be blown out in one second, after fully inhaling; the FEF, or forced expiratory flow, which reflects the flow of air coming out of the lungs during the middle portion of a forced exhalation; and the PEF, or peak expiratory flow, which is the maximal flow achieved when air is forcibly exhaled immediately after being inhaled.

Measurement models were performed separately for boys and for girls, and were adjusted for height, age, race and socioeconomic status.

At the conclusion of the study, the researchers found that exposure to nitrogen dioxideduring the first and second trimesters was associated with lower pulmonary function growth in both girls and boys in childhood. Among girls, exposure to nitrogen dioxide during the first trimester was associated with lower FEV1 growth and exposure to nitrogen dioxideduring the second trimester was associated with lower FEF growth. Among boys, nitrogen dioxide exposure during the first and second trimesters of pregnancy was associated with lower FVC growth. Exposure to particulate matter during the first trimester was associated with lower FEV1 and FVC growth in girls; similar exposures during the third trimester were associated with lower PEF and FEF growth among boys.

“This finding adds to the evidence that current air pollution levels continue to have adverse effects on human health,” Dr. Padula said. “Few studies have examined prenatal exposure to air pollution and subsequent lung function in childhood. These results suggest that we need to be doing a better job to reduce traffic-related air pollution.

Dr. Padula said she and her colleagues hope to conduct future studies on the role of genetic susceptibility to air pollution.

“Currently, our studies are examining the associations between prenatal air pollution and adverse birth outcomes,” she noted. “It would be useful to know what makes some people more or less susceptible to the adverse affects of air pollution so we might be able to provide more targeted public health advice.”

Study finds link between air pollution and increase in DNA damage

by ClickGreen staff.

 

A study in the Czech Republic has found a link between exposure to certain air pollutants and an increase in DNA damage for people exposed to high levels of the pollution.

 

They found that breathing small quantities of a polycyclic aromatic hydrocarbon (PAH), called benzo[a]pyrene (B[a]P), caused an increase in the number of certain ‘biomarkers’ in DNA associated with a higher risk of diseases, including cancer.

 

Air pollution is a major problem around the world, particularly in urban areas. In attempt to control regional air pollution levels, the EU has introduced legal limits for exposure to a variety of different airborne pollutants. For B[a]P , the EU air quality standard is 1 nanogram per metre3 (ng/m3) as an annual average that has to be attained where possible throughout the EU.

 

To measure the risk of DNA damage and risk to health caused by exposure to chemicals, such as PAHs, researchers sometimes use ‘biomarkers’ – these are biological features that can provide an indicative picture of risk and disease.

 

Previous studies have suggested that ‘DNA adducts’ can be used as biomarkers to measure exposure to PAHs. These are, in effect, small molecules, such as PAHs, bound to the DNA. Similarly, ‘chromosomal aberrations’ – structural changes to a stretch of DNA – can be used as biomarkers to demonstrate the effect of some pollutants on DNA.

 

To test whether there was a possible link between exposure to PAHs and the frequency of DNA adducts and chromosomal aberrations, the researchers, supported by the EU EnviRisk and INTARESE projects, examined DNA from 950 police officers and bus drivers in Prague.

 

The participants, drawn from three separate studies conducted over a five-year period, all worked outdoors for more than eight hours a day. Each carried a device to measure their personal exposure to PAHs and DNA was extracted from the participants’ white blood cells.

 

The researchers also tested a new technique for identifying chromosomal aberrations called ‘fluorescence in-situ hybridisation’, or FISH, which is much more sensitive than previous techniques.

 

The results revealed, for the first time, a significant relationship between exposure to PAHs, the number of DNA adducts and the number of chromosomal aberrations detected using FISH. In particular, PAH levels and the occurrence of the two biomarkers were higher in winter than in summer.

 

In one of the studies, average personal exposure to B[a]P and PAHs in January was measured as 1.58 ng/m3 and 9.07 ng/m3, respectively. In June, this dropped to 0.18 ng/m3 and 1.92 ng/m3.

 

The number of B[a]P-like DNA adducts and chromosomal aberrations were correspondingly much higher in January than in June. In fact, the number of DNA adducts strongly mirrored exposure to PAHs in the past 30 days.

 

These findings are of concern because exposure to more than 1 ng/m3 of B[a]P has been found to put people at higher risk of developing cancer later in life.

 

Previous studies have shown that DNA adducts can be an indicator for cancer several years after exposure and the findings of this study indicate that DNA adduct biomarkers and chromosomal aberrations measured using FISH could help health authorities identify individuals at higher risk of disease.

Air Pollution Increases Risk of Cervical, Brain, and Lung Cancers

By Linda Fugate PhD 

Originally posted here.

Urban air pollution from automobile traffic contains low levels of carcinogens in the form of ultrafine particles. Since large population numbers are exposed to this type of pollution, even a small increase in cancer risk can produce a significant number of cancer cases.

Ole Raaschou-Nielsen and colleagues in Denmark performed a study of 54,304 people exposed to different levels of air pollution over the time period 1971 to 2006.

“The airways are the primary target organs, but accumulating evidence from experiments in animals shows that ultrafine particles can translocate to other organs,” Raaschou-Nielsen explained. The research team collected records of 21 types of cancer over a period of 10 years. People who lived in areas with the highest air pollution numbers had elevated rates of cervical, brain, and lung cancers.

The participants were enrolled in the Danish Diet, Cancer, and Health cohort study. Air pollution was quantified by the concentrations of NO(x) molecules calculated from the Danish AirGIS modeling system. The researchers performed separate studies for lung cancer and for cancers of all other sites.

Lung cancer rates were 30 percent higher in participants who lived in the highest air pollution areas, compared with the lowest pollution areas. “The results indicated stronger associations among nonsmokers, among participant[s] with longer school attendance, and among those with relatively low dietary intake of fruit”, Raaschou-Nielsen reported.

Inhaled carcinogens can reach any part of the body through the bloodstream. In addition, Raaschou-Nielsen reported that ultrafine particles can reach the brain through the olfactory nerves that serve the nose. An inflammatory response may be one step in the development of brain cancer, which showed significantly increased rates in people exposed to the highest levels of air pollution.

The association between high automobile traffic and increased rates of cervical cancer was not explained by any known mechanism. Raaschou-Nielsen pointed out that the researchers had no information on rates of human papillomavirus (HPV) infection, which is recognized as a cause of cervical cancer.

“It is possible that HPV infection is more prevalent among women living in areas with heavy traffic and air pollution,” he noted. Further research is needed to determine whether it was the air pollution itself or some related factor that caused higher rates of cervical cancer.

References:

1. Raaschou-Nielson O et al, “Air pollution from traffic and cancer incidence: a Danish cohort study”, Environmental Health 2011; 10: 67.http://www.ncbi.nlm.nih.gov/pubmed/21771295

2. Raaschou-Nielson O et al, “Lung cancer incidence and long-term exposure to air pollution from traffic”, Environ Health Prespect 2011; 199: 860-865.
http://www.ncbi.nlm.nih.gov/pubmed/21227886

3. National Environmental Research Institute. AirGIS. Web. Dec. 6, 2011.
http://www.dmu.dk/en/air/models/airgis

Reviewed December 12, 2011
by Michele Blacksberg RN
Edited by Jody Smith