Breast health begins early in life

We’re funding research exploring how a girl’s BMI and when she starts puberty affect her breast cancer risk in later life

Young girls eating lunch in the school canteenWith breast cancer now the most common cancer globally, it’s important to look at why so many women develop this disease.

We’re funding a study by Jennifer Baker at Frederiksberg Hospital in Denmark which looks at how a woman’s body size throughout her life affects her risk of breast cancer – just 1 of an amazing 44 studies we’ve funded on breast cancer since we were set up in 1982.

Breast cancer is – like many cancer types – a complex disease with many different subtypes, categorised both by how aggressive the cancer is and where in the breast the tumour develops. Post-menopausal breast cancer – which develops after a woman has stopped having periods – is more common, while pre-menopausal breast cancer can be harder to treat (sometimes because it is diagnosed later).

We already have strong evidence about what can cause or protect against breast cancer, which makes the early results from Dr Baker’s study so interesting. Her research shows that girls aged 7–13 with a higher body mass index (BMI) have GREATER protection against pre- and post-menopausal breast cancer later in life (see papers in Breast Cancer Research and The European Journal of Pediatrics).

This research is puzzling as we also know that:

  • Greater weight at birth INCREASES the risk of pre-menopausal breast cancer.
  • Being overweight or obese INCREASES the risk of post-menopausal breast cancer.
  • Gaining weight as an adult INCREASES the risk of breast cancer.

These risk factors are explained on our breast cancer page.

This highlights how complex the relationship between breast cancer and weight really is – and why studies such as Dr Baker’s are so important in understanding the science and giving women the best information about how to reduce their risk.

Breast cancer researchers are now looking into why a higher BMI at that age may reduce the risk, exploring questions around:

  • Puberty: a higher BMI can delay puberty. Delayed puberty means less exposure to the hormones that are associated with a higher breast cancer risk.
  • Breast tissue: fatty tissue in the breast is linked with a lower risk of breast cancer – and the formation of breast tissue begins in childhood.

> Explore all the breast cancer research we’re funding

It can be scary to think that 1 in 8 women will be diagnosed with breast cancer in their lifetime. That’s why we fund research and share health information to help fewer people develop a preventable cancer. Can you help us?

> Make a donation to our work today

> Order a free Women’s health guide, which shows how you can reduce your risk of  female cancers

> Read Dr Baker’s blog exploring this research