Most people associate high BMI with lifestyle diseases like heart problems and diabetes. But now, mounting scientific evidence shows that a high BMI can also increase the risk of breast cancer, especially in postmenopausal women.According to a large study supported by the World Health Organization (WHO) and published in CANCER journal, being overweight or obese significantly raises a woman’s breast cancer risk—particularly if she already has cardiovascular disease.
High BMI leads to increased risk of breast cancer after menopause
Researchers analysed health records of over 168,000 women from two large databases: the European Prospective Investigation into Cancer and Nutrition (EPIC) and the UK Biobank. All women were free of cancer, heart disease, and type 2 diabetes when the study began.After an average follow-up of 11 years, 6,793 women developed postmenopausal breast cancer. A clear pattern emerged: every 5-point increase in BMI was linked to 31% higher breast cancer risk in women who later developed cardiovascular disease and 13% higher risk in those without heart diseaseThese findings show that high BMI significantly increases the likelihood of breast cancer, and the risk gets even worse when heart problems are also present.
Excess weight combined with heart disease raises cancer risk even more
The study found that women who were overweight (BMI > 25) and also had heart disease faced much higher risks than women without these conditions. Specifically, there were 153 additional breast cancer cases per 100,000 women per year among those with both high BMI and cardiovascular diseaseThis means that excess weight and heart disease together act like a cancer risk multiplier, putting women in an even more vulnerable category.
Why excess weight raises the risk of breast cancer
Obesity doesn’t just sit on the surface of your body—it affects nearly every biological system. According to the American Cancer Society, excess body fat increases breast cancer risk, especially after menopause:
- Increased estrogen levels: Fat tissue produces estrogen, which can feed hormone-sensitive breast cancers.
- Higher insulin and insulin-like growth factor (IGF-1): These hormones can speed up the growth of abnormal cells.
- Chronic inflammation: Being overweight leads to low-grade, long-lasting inflammation in the body, a known cancer risk factor.
- Reduced cell death: Fat-related hormone imbalances may help abnormal cells live longer than they should.
- These processes are especially active in postmenopausal women, making high BMI a serious risk factor for breast cancer in this group.
Excess weight linked to multiple types of cancer, not just breast cancer
This study supports what many others have found: excess weight doesn’t just increase breast cancer risk—it’s connected to at least 12 other cancers, including
- Uterine cancer
- Liver cancer
- Kidney cancer
- Pancreatic cancer
- Colorectal cancer
A separate study published in Nature Communications found that obese women are more likely to be diagnosed with larger, more advanced breast tumours, especially in hormone-receptor-positive cancers. This not only increases cancer risk but also delays detection and worsens outcomes.
Postmenopausal women should monitor BMI to lower cancer risk
With this growing body of research, doctors are now urging postmenopausal women to:
- Regularly monitor their BMI
- Maintain a healthy body weight through physical activity and a balanced diet
- Undergo heart health checks for issues like hypertension or high cholesterol
- Talk to their doctor about more frequent mammograms if they have additional risk factors
This study suggests that higher BMI leads to an increased risk of breast cancer, especially in postmenopausal women with heart disease. Excess weight not only raises the chance of developing breast cancer—it may also make tumours harder to detect and treat.With obesity rates rising globally, especially in countries like India, it’s more important than ever to raise awareness, promote healthy lifestyles, and ensure women receive risk-based breast cancer screenings. Simple steps like weight management, early screening, and lifestyle changes can go a long way in protecting women from one of the most common cancers worldwide.Also Read: Ayurvedic herbs to fight against thyroid issues: 3 powerful herbs to support metabolism and fight stress
