The risk of developing breast cancer is probably higher in younger women who smoke heavily before the menopause, especially before they give birth, according to a US study.
But women who smoked after menopause tended to reduce their risk of developing breast cancer as it appeared to lower their levels of oestrogen.
Breast cancer rates in almost 150,000 people were found to be higher among the younger women who smoked the most.
The study authors, writing in the Archives of Internal Medicine, said: “Smoking before menopause was positively associated with breast cancer risk.”
For those who started using tobacco before giving birth for the first time, smoking the equivalent of 20 cigarettes a day for 20 years raised the risk of breast cancer by 18%.
No significant association was seen between passive smoking, or light and moderate smoking, and breast cancer. But women who smoked heavily and took up the habit early in life were at increased risk.
The new study was led by Dr Fei Xue at Harvard Medical School in Boston and was based on data from the Nurses’ Health Study, a major US investigation of the factors which damage women’s health.
- Xue F, et al. Cigarette Smoking and the Incidence of Breast Cancer. Arch Intern Med. 2011;171(2):125-133.
How aware do you think young women are of the link between smoking and breast cancer?