Older women carrying excess weight have a higher risk of a life-threatening double-whammy, a new study says.
Women past menopause with a higher body mass index (BMI) were more likely to develop breast cancer if they had heart disease, researchers reported July 7 in the journal Cancer. BMI is an estimate of body fat based on height and weight.
Women with heart disease had a 31% increased risk of breast cancer for every 5-point increase in their BMI, results show.
By comparison, women without heart problems had a 13% increased risk for every 5-point BMI increase, results show.
“This suggests that among postmenopausal women with cardiovascular disease, prevention of obesity may lead to a greater reduction in breast cancer incidence compared to the general population,” concluded the research team led by Heinz Freisling, a scientist of nutrition and metabolism with the International Agency for Research on Cancer.
For the study, researchers pooled data from two large-scale European health studies — the ongoing UK Biobank research project and the European Prospective Investigation Into Cancer and Nutrition (EPIC).
They wound up with data on nearly 169,000 postmenopausal women, including almost 6,800 who developed breast cancer after an average follow-up of nearly 11 years.
Researchers estimate that the combination of excess weight and heart disease could cause an additional 153 cases of breast cancer per 100,000.
On the other hand, developing type 2 diabetes did not seem to affect women’s breast cancer risk, researchers found.
“Emerging experimental research suggests that certain types of cardiovascular disease — such as myocardial infarction [heart attack] — can accelerate breast cancer growth by reprogramming of the innate immune system,” researchers wrote.
Proteins secreted after heart failure have been shown to promote tumor formation and accelerate cancer growth, researchers said.
“The findings of this study could be used to inform risk-stratified breast cancer screening programs,” Freisling said. “This study should also inspire future research to include women with a history of cardiovascular diseases in weight loss trials for breast cancer prevention.”