Non-smoking women who breastfeed their babies for at least six months may have a reduced risk of developing breast cancer, a new study indicates.

The benefits of breastfeeding are well-established. Research has shown that children who are breastfed are less likely to develop a number of conditions, such as asthma, eczema and chest infections. While mothers who breastfeed have a reduced risk of developing conditions such as heart disease and diabetes. 

Spanish scientists set out to investigate the relationship between pregnancy, breastfeeding and breast cancer. They analysed the health records of over 500 women who had been diagnosed with breast cancer between 2004 and 2009.

The women were aged between 19 and 91.

The scientists looked at things such as how old the women were when they were diagnosed with cancer, whether they had any family history of the disease, whether they were obese, whether they smoked and how long they breastfed for.

The study found that overall, women who had given birth and had breastfed were diagnosed with cancer at a later age, irrespective of whether there was a family history of the disease.

However those who did not smoke and had breastfed for at least six months were diagnosed even later - around 10 years later than non-smokers who breastfed for less than six months.

On the other hand, women who smoked tended to be diagnosed with breast cancer when they were younger and did not appear to gain any significant health benefits from breastfeeding for longer.

"The results suggest that for non-smokers, breastfeeding for more than six months not only provides children with numerous health benefits, but it also may protect mothers from breast cancer," commented Dr Emilio González-Jiménez of the University of Granada.

Details of these findings are published in the Journal of Clinical Nursing.