Led by researchers at the University of New South Wales, a new study looked at six Australian cohort studies, which included a total of 214,536 women, to investigate if changing certain lifestyle habits could possibly prevent future cases of pre-menopausal and post-menopausal breast cancer.
The findings, published in the International Journal of Cancer, showed that for pre-menopausal women, regular alcohol consumption explains 12.6% of breast cancer cases in the next decade, and using oral contraceptives for five years or more accounts for 7.1%.
These factors combined account for 18.8% of future breast cancer cases.
For post-menopausal women, being overweight or obese explains 12.8% of breast cancer cases in the next ten years, regular alcohol consumption 6.6%, and current use of menopausal hormone therapy (MHT) 6.9%.
Combined, the three factors account for 24.2% of future cases.
“We found that current levels of overweight and obesity (defined as a body mass index of 25 or higher) are responsible for the largest proportion of preventable future breast cancers – more specifically, 17,500 or 13% of breast cancers in the next decade,” says study author Dr Maarit Laaksonen.
“Regular alcohol consumption is the second largest contributor – 13% of pre-menopausal and 6% of post-menopausal breast cancers, that is 11,600 cases over the next 10 years, are attributable to consuming alcohol regularly.”
The researchers also point out that this is the first study to show that regular alcohol consumption is a leading modifiable cause of breast cancer for pre-menopausal women.
Although the current Australian recommendation is to drink no more than two alcoholic drinks per day on average, the study found that risk of breast cancer increased with an average consumption of just one alcoholic drink per day.
Dr Laaksonen also added that, “Our findings support the current Australian and international recommendations of using MHT for the shortest duration possible, and only to alleviate menopausal symptoms, not for the prevention of chronic disease.”
She also added that women should not interpret the results as meaning they should stop taking the contraceptive pill.
“When it comes to oral contraception (OC), it is not recommended that women restrict their use of OCs – the latest position statement from Cancer Council Australia says that over the course of a woman’s lifetime, the net effect of OCs is actually cancer-protective, as they provide long-term protection against endometrial and ovarian cancers, meaning that the potential benefits, including reproductive benefits, outweigh the harms.” – AFP Relaxnews