Breast cancer 'linked' to chemical jobs, Stirling study suggests
Women working in jobs where they are exposed to certain chemicals may have a greater risk of developing breast cancer, a study suggests.
The international research by the Occupational and Environmental Health Research Group at Stirling University studied more than 2,000 women.
They found that women who worked for 10 years in jobs classified as "highly exposed" increased their risk by 42%.
The team has called for further research on the subject.
Researchers from Canada, the US and the UK all took part in the study, which monitored 1,006 women with breast cancer and 1,147 without the disease in Southern Ontario, Canada.
Dr James Brophy, from Occupational and Environmental Health Research Group (OEHRG), said: "Breast cancer causality is complex. It is believed to result from a combination of factors including genetic, hormonal and lifestyle influences as well as environmental exposures.
"However, studies have shown that breast cancer incidence rose throughout the developed world during in the second half of the 20th Century as women entered industrial workplaces and many new and untested chemicals were being introduced.
"Diverse and concentrated exposures to carcinogens and hormone disrupting chemicals in some workplaces can put workers at an increased risk for developing cancer."
The researchers said although the study focused on Ontario, where there is extensive manufacturing and agriculture, its findings have relevance to women working in a variety of industries across the globe.
Professor Andrew Watterson, head of the OEHRG and a co-investigator on the project, said: "Many workers face multiple exposures to chemicals, not only from their employment, but from their everyday environment.
"Many of the women included in the study were exposed to a virtual 'toxic soup' of chemicals. Untangling work and wider factors in the possible causes of breast cancer is an important global issue."
The study found several occupational sectors in which there appeared to be an elevated breast cancer risk, including manufacture of plastics for use in the automobile industry, farming and metalworking.
Some experts have cast doubt on whether the statistical analysis used to interpret the data in the study gives an accurate assessment of true risk.
In a statement the American Chemistry Council also expressed its concerns, saying that the authors could be "over-interpreting their results and unnecessarily alarm workers".
It added: "This study included no data showing if there was actual chemical exposure, from what chemicals, at what levels, and over what period of time in any particular workplace.
"Although this is an important area of research, these findings are inconsistent with other research. This study should not be used to draw any conclusions about the cause of cancer patterns in workers."
Dr Brophy called for further research to be funded as a matter of urgency.
He said: "The study of occupational risks for breast cancer is a neglected area of research.
"This study points to the value of including detailed work histories in the environmental and occupational epidemiology of breast cancer."