Cleaning up could be literally killing the women - new research shows that household cleaning products may contribute to breast cancer, as they may contain endocrine disrupting chemicals or mammary gland carcinogens. The study has been published in Environmental Health.
Participants were 787 Cape Cod, Massachusetts, women diagnosed with breast cancer between 1988 and 1995 and 721 controls. Telephone interviews asked about product use, beliefs about breast cancer origins, and established and suspected breast cancer risk factors.
Breast cancer risk increased two-fold in the highest compared with lowest quartile of self-reported combined cleaning product use. Little association was observed with pesticide use.
The research, by the US Silent Spring Institute, an organisation that looks for links between chemicals and women's health, said in animal studies various compounds were linked to cancer. These include artificial musks added to air fresheners and detergents to make them smell better.
To evaluate potential recall bias, the researchers stratified product-use odds ratios by beliefs about whether chemicals and pollutants contribute to breast cancer, and they compared these results with odds ratios for family history (which are less subject to recall bias) stratified by beliefs about heredity.
However, the researchers cautioned, "The results also highlight the difficulty of distinguishing in retrospective self-report studies between valid associations and the influence of recall bias. Recall bias may influence higher odds ratios for product use among participants who believed that chemicals and pollutants contribute to breast cancer."
That is, they say their findings could have been distorted by the patients looking for something to blame their ill health on. This so-called recall bias could lead them to over-estimate their use of air fresheners, mould and mildew removers while healthy. Cancer patients were also more likely than other women to think chemicals caused the disease.
Still because exposure to chemicals from household cleaning products is a biologically plausible cause of breast cancer, further studies were required, they stressed.