issues researchers found that women who reported high use of cleaning products, air fresheners and insect repellents had a higher risk of breast cancer compared with women who reported using them sparingly: however they…
US researchers found that women who reported high use of cleaning products, air fresheners and insect repellents had a higher risk of breast cancer compared with women who reported using them sparingly: however they cautioned that because the study relied on women’s recall of product use, and their beliefs about how such products might contribute to cancer development could have influenced their recall, it should not be taken as proof of a link, but sufficient reason to research it more thoroughly.
You can read about how Dr Julia Brody, from the Silent Spring Institute, whose headquarters are in Newton, Massachusetts, and colleagues arrived at these findings in a report that was published online in the journal Environmental Health on 20 July.
For the study, which Brody and colleagues believe to be the first to investigate cleaning products and breast cancer, they conducted telephone interviews with 787 women in Cape Cod, Massachusetts, who were diagnosed with breast cancer between 1988 and 1995 and 721 women picked at random for comparison.
Brody told the press they found that:
“Women who reported the highest combined cleaning product use had a doubled risk of breast cancer compared to those with the lowest reported use.”
She said use of air fresheners and products to control mold and mildew were linked to increased risk.
In the telephone interviews the researchers asked the women about product use, their beliefs about the causes of breast cancer, and their established and suspected breast cancer risk factors.
As well as looking for any links between product use and breast cancer risk, the researchers evaluated potential recall bias by doing what they called a “stratified analysis”. They did this in two ways:
1. In the first stratified analysis they looked at links between product use and breast cancer incidence arranged according to beliefs about whether chemicals and pollutants contribute to breast cancer.
2. In the second they looked at links between family history and breast cancer incidence and also arranged them according to beliefs about how much family history contributes to breast cancer.
The logic behind this was they thought since family history was less likely to be influenced by recall bias, any recall bias due to beliefs would stand out in comparison.
The results showed that:
* Risk of developing breast cancer was twice as high in the 25 per cent of women who reported the most combined cleaning product use compared to the 25 per cent who reported the least (they compared the uppermost “quartile” with the lowest: adjusted odds ratio OR was 2.1, with 95 per cent confidence interval CI ranging from 1.4 to 3.3).
* The result was similar for combined air freshener use (uppermost to lowest quartile comparison showed an adjusted OR = 1.9, with 95% CI ranging from 1.2 to 3.0).
* There was no such link with pesticide use.
* In the stratified analyses, the odds ratios for cleaning products linked to breast cancer risk were higher among participants who said they believed that pollutants contributed “a lot” to breast cancer, and tended towards null among participants who did not report such a belief.
* In comparison, the odds ratio for breast cancer and family history was also higher among women who believed that heredity contributed “a lot”, and it was not so high among the rest (OR 2.6 versus 0.7 respectively: no overlap in the CIs).
The researchers concluded that these results suggest that cleaning product use contributes to increased breast cancer risk.