Pre-childbirth solvent exposure raises breast cancer risk

The timing of exposure to organic solvents – such as those found in cleaning products and industrial chemicals – may affect breast cancer risks in women, according to a study from the US National Institute of Environmental Health Sciences.

Christine Ekenga and colleagues found that women exposed to organic solvents before having their first child had a higher risk of developing hormone-related breast cancer, that is promoted by the presence of oestrogen or progesterone.

The group used data from the Sister Study, a project following a cohort of over 50,000 women whose sisters have been diagnosed with breast cancer, all of whom were healthy at the time they enrolled. Questionnaires were used to monitor various risk factors, including potential exposure to organic solvents during work, and follow-up studies tracked whether they went on to develop breast cancer.

While lifetime exposure to solvents was found not to affect the overall breast cancer risk, the risk was found to be higher for women who had started to work with solvents before having their first child. This indicates the breasts could be more vulnerable to chemical exposure during the period of development after puberty but before childbirth. The group say women who are regularly exposed to organic solvents – for example medical technicians, cleaners and factory workers – should minimise their exposure using personal protective equipment.