Obese women have higher risk of suffering breast cancer, Spanish study finds

A total of 524 women with breast cancer participated in the study. The researchers found that women who started menstruating at a very early age -- between 9 and 10 years -- developed breast cancer at a younger age.

Obese women develop breast cancer at a younger age than other women. Furthermore, the likelihood of developing breast cancer is much higher in patients with morbid obesity.

This is one of the main conclusions drawn in an article recently published in the Spanish journal Nutrición Hospitalaria by the University of Granada research group CTS 367, coordinated by the Nursery Department professor María José Aguilar Cordero.

The researchers examined a sample of 524 women diagnosed with breast cancer who were treated at the university hospital San Cecilio from January 2009 to September 2010 in Granada, Spain. They assessed the nutritional status of these patients (normal weight, obesity and morbid obesity) and their age at diagnosis. Women with a family history of breast cancer were separated from those lacking it.

The researchers found that obesity in women is associated with diagnosis of breast cancer at a younger age. This finding contrasts with the results obtained in previous studies that demonstrated that individuals with higher body mass index had lower risk of suffering breast cancer.

Age At First Menstruation

The University of Granada researchers found that women diagnosed with breast cancer at an earlier age were those who started menstruating when younger than 10 years. Thus, age at menarche is determinant in the development and diagnosis of breast cancer, especially in women with morbid obesity.

Therefore, although genetics and family history of cancer are very relevant factors (up to 18% of breast cancer in obese women had a genetic factor), this study demonstrated that obesity -- especially the most severe cases -- is the most relevant factor in early development of breast cancer.