Air fresheners and some cleaning products increase the risk of breast cancer, a study suggests.
Women who regularly used a combination of cleaning products were twice as likely to have breast cancer as other healthy women, US scientists found. The strongest link was between cancer and air fresheners and mould and mildew removers.
Increased incidence of cancer was also linked to insect repellents.
But there was no connection with home and garden pesticides and surface and oven cleaners.
The researchers admitted the study was imperfect because they asked cancer sufferers to remember whether they had used cleaning products and the strongest correlation was found among those who believed chemicals contributed to the disease. But they defended the findings as "biologically plausible", saying many air fresheners and cleaning products contained endocrine-disrupting chemicals linked to breast cancer in laboratory experiments on rodents.
They said synthetic musks and phthalates were commonly used in solid and spray fresheners and antimicrobials, phthalates and alkylphenolic surfactants were found in many mould and mildew products.
Researchers from Silent Spring Institute, Massachusetts, and Boston University interviewed 787 women with breast cancer and 721 healthy women for the study.
The women – who all lived in the Cape Cod area of Massachusetts – were asked about their use of cleaning products and pesticides, and split into four groups ranging between high and low users.
According to the study, published in the journal Environmental Health: "Women who reported the highest combined cleaning product use had a doubled risk of breast cancer compared to those with the lowest reported use. Use of air fresheners and products for mould and mildew control were associated with increased risk."
The authors said their work was the first into a potential link between breast cancer and cleaning products.
Breast Cancer Research UK and Breakthrough Breast Cancer, which campaign against confirmed carcinogens such as cigarette smoke, said conclusions could not be drawn from it because it suffered from "recall bias". "This small study asked women with breast cancer to remember how often they used cleaning products many years ago," said Jessica Harris, Cancer Research's health information officer.
"It only linked the products to breast cancer among women who believed chemicals could cause breast cancer, and not in women who didn't think such products caused the disease."
Philip Malpass, director general of the UK Cleaning Products Industry Association, said UK brands did not contain substances shown to cause cancer, adding: "We agree with the US authors who recognise that these results could arise simply from selective or biased recall of cleaning product use."
Clare Dimmer, chair of trustees at Breast Cancer UK, said: "Although we will have to wait for more research before we can be sure about the link, some women already diagnosed with the disease may want to take a precautionary approach and review the levels of potentially-hazardous chemicals in the products they use."Reuse content