May 2026
Breast cancer risk reduction needs lifestyle modification throughout the life course
By Melanie Hinze
Alcohol consumption, overweight or obesity, and being without a partner are each independently associated with an increased risk of breast cancer in Australian women from midlife into older age, according to new research.
The longitudinal cohort study, published in BMJ Open, used data from the Australian Longitudinal Study on Women’s Health 1946 to 1951 birth cohort linked with the Australian Cancer Database.
Of 12,782 women followed from 1996 to 2019, 941 (7.4%) were diagnosed with breast cancer during the study period.
The study authors found that women who consumed alcohol had a higher risk of breast cancer compared with nondrinkers, regardless of how much alcohol they drank.
‘This reinforces that there is no safe threshold of alcohol consumption for breast cancer risk,’ Professor Xue Qin Yu, senior author of the paper, and Professor of Cancer Epidemiology at The Daffodil Centre, Sydney, told Medicine Today.
Women who were overweight or obese had a 23% higher hazard of breast cancer compared with those who were underweight or of acceptable weight, and this gap widened progressively over 20 years of follow up.
Professor Yu said this suggested that weight management should be framed not only around cardiovascular or metabolic health, but also cancer prevention, particularly breast cancer.
Non-partnered women had a 32% higher hazard of breast cancer than partnered women, a finding the authors suggested may reflect the protective effects of social support, health-seeking behaviour and reduced stress associated with partnership.
Smoking, hormone replacement therapy use and oral contraceptive use were not significantly associated with breast cancer incidence in this cohort.
Professor Yu said the study underscored the ongoing relevance of lifestyle modification throughout the life course.
‘This study shows that modifiable lifestyle factors such as maintaining a healthy weight, limiting alcohol intake and avoiding smoking are associated with a lower risk of breast cancer from mid-life into older age,’ he said.
‘Importantly, these associations persist even among women aged 70 years and over, highlighting that preventive lifestyle advice remains relevant throughout the life course.’
He recommended that for breast cancer prevention, GPs prioritise conversations about alcohol consumption and healthy weight, particularly in midlife, because these modifiable factors meaningfully influenced risk over time.