Weight-associated breast cancer risk higher in women with cardiovascular disease – study

Excess weight is linked to a significantly higher risk of breast cancer in postmenopausal women who develop heart disease, new research suggests.

Each 5 kg/m² increase in body mass index (BMI) was associated with a 31 per cent higher risk of breast cancer in women who developed cardiovascular disease during follow-up, compared to a 13 per cent increase in those who did not.

Being overweight – defined as a BMI of 25 kg/m² or above – and having cardiovascular disease together were estimated to lead to 153 additional breast cancer cases per 100,000 people per year.

Dr Heinz Freisling, who led the study, said: “The findings of this study could be used to inform risk-stratified breast cancer screening programmes.

“This study should also inspire future research to include women with a history of cardiovascular diseases in weight loss trials for breast cancer prevention.”

Researchers analysed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) and UK Biobank studies, covering 168,547 postmenopausal women who had no history of cardiovascular disease or type 2 diabetes when they joined the study.

BMI is a measure of body fat based on height and weight. Cardiovascular disease includes heart conditions such as heart attack and stroke, which affect the heart and blood vessels.

After a median follow-up of 10.7 years in EPIC and 10.9 years in UK Biobank, 6,793 women developed breast cancer.

The analysis showed that while higher BMI is a known risk factor for breast cancer after menopause, the risk was significantly higher among women who went on to develop cardiovascular disease.

By contrast, developing type 2 diabetes did not appear to alter breast cancer risk. Women with or without diabetes showed a similarly elevated risk associated with higher BMI.

The results suggest that postmenopausal women with cardiovascular disease may require more tailored breast cancer monitoring, particularly if they are overweight.