Weight gain, late motherhood increases breast cancer risk

Significant weight gain after the age of 20, combined with late motherhood or never having children, can nearly triple a woman’s risk of developing breast cancer, according to a British study presented at the European Congress on Obesity.

 

Researchers analysed data from 48,417 women with an average age of 57 and a median body mass index (BMI) of 26. Participants were categorised based on the timing of their first pregnancy—early (before 30), late (30 or older), or nulliparous (never having given birth)—as well as their weight gain after 20.

 

Over an average follow-up period of 6.4 years, 1,702 women were diagnosed with breast cancer. Women who gained more than 30 per cent of their body weight after 20 and either had their first child after 30 or never gave birth were 2.7 times more likely to develop breast cancer compared with women who had children earlier and less than a 5 per cent increase in adult weight.

 

Breast cancer diagnosis in women is steadily rising, and more women are having children later in life. “Information about how age of motherhood and weight gain affect the risk of breast cancer would allow us to better work out who is most at risk of the disease and target lifestyle advice accordingly,” noted the lead researcher.

Health