Nav: Home

Occupational health study links air pollution and cancer

November 22, 2018

University of Stirling experts have discovered new evidence of the link between air pollution and cancer as part of a new occupational health study. The team, from the Faculty of Health Sciences and Sport, analysed the case of a woman who developed breast cancer after spending 20 years working as a border guard at the busiest commercial border crossing in North America.

The woman was one of, at least, five other border guards who developed breast cancer within 30 months of each other and, at another nearby crossing, a cluster of seven other cases was noted.

Dr Michael Gilbertson, who worked with colleague Dr Jim Brophy, said their findings "infer a causal relationship" between breast cancer and very high exposures to traffic-related air pollution containing mammary carcinogens. A link between nightshift work and cancer was also identified.

Dr Gilbertson said: "This new research indicates the role of traffic-related air pollution in contributing to the increasing incidence of breast cancer in the general population.

"With this new knowledge, industry and government can plan for new designs for industrial and commercial facilities to cut down on the occupational exposures to traffic-related air pollution and for scheduling shift work to minimise disruption of sleep patterns."

Drs Gilbertson and Brophy focused on the worker compensation case of the woman, who was employed by the Canada Border Services Agency for two decades at the Ambassador Bridge, which crosses the Detroit River between Windsor, Ontario, and Detroit, Michigan.

The bridge - the busiest commercial border crossing in North America - carries 12,000 trucks and 15,000 cars each day. The air pollution is severe and border guards in the traffic booths inhale many carcinogens, including those that result in breast cancer.

The woman - one of at least five colleagues who developed breast cancer within 30 months of each other - was diagnosed with her first bout of breast cancer at the age of 44 and second at 51. Notably, another cluster of seven cancer cases occurred at a second crossing point, the Detroit-Windsor Tunnel, which lies four miles from the bridge.

The cluster of cases in staff at the bridge was 16 times higher than the rate in the rest of the country - there is less than a one in 10,000 probability that this could have occurred by chance. In addition, the clusters were characterised by breast cancer cases that were early onset and premenopausal with recurrences.

The scientists analysed the circumstances of the case - heard by the Workplace Safety and Insurance Appeals Tribunal (WSIAT) - by applying the Bradford Hill criteria - a group of nine principles that are useful in establishing epidemiologic evidence of a causal relationship between a presumed cause and an observed effect. The criteria considers strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment and analogy.

The case focused on whether the woman had a genetically inherited predisposition to develop breast cancer because of dysfunctional BRCA1/2 tumour suppressor genes. It was found that her BRCA1/2 tumour suppressors were not working - but that was not connected to her inherited genes. This condition is known as "BRCAness" and is sporadic, rather than an inherited breast cancer.

The Stirling team investigated whether the dysfunction was potentially caused by occupational exposures to pollution. A review of previous research confirmed that BRCA1 can be "silenced" by exposures to dioxins and polycyclic aromatic hydrocarbons - both found in exhaust fumes.

In addition, other research has shown that BRCA2 is rapidly degraded in the presence of aldehydes - also components of exhaust fumes.

"There is much more research to be undertaken," Dr Gilbertson said. "But we now have plausible mechanisms for inferring how the BRCA1/2 tumour suppressors in this highly-exposed border guard became dysfunctional and likely contributed to the ongoing epidemic of sporadic, early onset, premenopausal breast cancer among her colleagues.

"These outbreaks of breast cancer represent a new occupational disease that we are provisionally calling 'occupational BRCAness'."

The front-line workers also identified nightshift work as a potential contributing factor to their high incidence of breast cancer.

Drs Gilbertson and Brophy considered whether nightshift work might exacerbate the exposures to mammary carcinogens in traffic-related air pollution. They pointed to a previous study involving rats that found those exposed to continuous daylight developed tumours 36 per cent faster - and had 60 per cent more tumours - than those subjected to a normal photoperiod.

Significantly, the WSIAT rejected the woman's case.

Reflecting on the findings, Dr Gilbertson continued: "Reweighing the scientific evidence using a consensus medico-legal framework - the Hill Bradford criteria - enabled us to show the amount of evidence that the WSIAT had ignored in dismissing this worker compensation case."

He added: "This kind of forensic research depends on asking new questions based on conclusions from the existing evidence and a willingness to follow leads into unfamiliar areas of science.

"The gratifying part was to find that other scientists in other disciplines had already supplied credible answers that could then be assembled into the Hill's framework of indicia for this specific case which can explain the clusters."
-end-
The study, Causality advocacy: Workers' compensation cases as resources for identifying and preventing diseases of modernity, is published in New Solutions.

University of Stirling

Related Breast Cancer Articles:

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.
Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.
Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.
More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.
Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.
Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.
Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.
Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.
Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.
Does MRI plus mammography improve detection of new breast cancer after breast conservation therapy?
A new article published by JAMA Oncology compares outcomes for combined mammography and MRI or ultrasonography screenings for new breast cancers in women who have previously undergone breast conservation surgery and radiotherapy for breast cancer initially diagnosed at 50 or younger.
More Breast Cancer News and Breast Cancer Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.