Smoking may initiate breast cancer
J Natl Cancer Inst 2013;105:515-525
Women who start smoking before giving birth to their first baby are especially likely to develop breast cancer.
American researchers analysed data from 73,388 women. Of these, 3,721 developed invasive breast cancer during a median follow-up of 13.8 years. Current and former smokers were 24 per cent and 13 per cent respectively more likely than women who had never smoked to develop breast cancer. Women who started smoking before menarche (61 per cent increase) or after menarche but at least 11 years before their first birth (45 per cent increase) were particularly likely to develop breast cancer.
The authors incorporated these results in a meta-analysis that also included 14 previous studies. Based on analysis of 991,100 women, current and former smoking increased the risk of breast cancer by 12 per cent and 9 per cent respectively.
Another meta-analysis of 774,430 women, suggested starting smoking before giving birth for the first time increased breast cancer risk by 21 per cent. The relationship between early life smoking and breast cancer plus 'the lack of a consistent relationship' with smoking later in life, suggests smoking 'may play a greater role in the initiation than the progression of breast cancer'.
Mood and alcohol abuse
AAMA Psychiatry (2013) doi:10.1001/jamapsychiatry.2013.1098