The most dangerous of such chemicals are: pesticides; sex and growth hormones that bolster meat and dairy production; plastic wrapping and packaging; food colouring dyes; and radioactive pollutants from nuclear plants.

In 1993, researchers found that women with the highest food levels of DDE were at a four times greater risk for breast cancer, compared to those with the lowest levels (J Nat Cancer Inst, 1993; 85: 648-52). In 1994, Canadian researchers reported that concentrations of a wide range of carcinogenic and pseudo oestrogenic pesticides and pollutants were higher in the fat and blood of women with oestrogen sensitive breast cancers than in healthy women (J Nat Cancer Inst, 1994; 86: 232-4).

Dark and deadly

Another major lifestyle hazard is hair dye. Permanent and semipermanent hair dyes are a witches' brew of carcinogens and contaminants, including diaminotoluene, diaminoanisole and other phenylenediamine dyes; dioxane, found in detergents and solvents; nitrosamines; and formaldehyde releasing preservatives. Both animal and human studies show that the body rapidly absorbs chemicals in permanent and semipermanent dyes through the skin during the more than 30 minutes the dyes remain on the scalp.

Five studies in the late 1970s found links between use of dyes and breast cancer. A 1976 study reported that 87 of 100 breast cancer patients had been long term hair dye users (NY State J of Med, 1976; 76: 394-6).

A 1979 US study found a significant relationship between frequency and duration of hair dye use and breast cancer (J Nat Cancer Inst, 1979; 62: 277-83). Those at greatest risk are 50 to 79 year olds, suggesting that the cancer takes years to develop. Women who start at age 20 have over twice the risk of 40 year olds.

Another conclusion is that the darker the shades of permanent and semipermanent dyes, the higher the risks of breast cancer.

Finally, one study found that women who dye their hair to change its colour, rather than masking greyness, were at a three fold risk (J Nat Cancer Inst, 1980; 64: 23-8).

Recently, a jointly funded American Cancer Society and Food and Drug Administration study admitted a fourfold increase in relatively uncommon cancers, including non Hodgkin's lymphoma (the cancer that killed dark haired Jacqueline Onassis) and multiple myeloma in hair dye users (J Nat Cancer Inst, 1994; 86: 215-310).

!ADr Samuel Epstein and David Steinman

Dr Samuel Epstein, author of The Politics of Cancer, is a world authority on environmental causes of cancer. His and David Steinman's book, The Breast Cancer Prevention Program, is available in paperback from Macmillan, 1633 Broadway, New York, NY 10019-6785 US. $14.95).