MONDAY, June 6 (HealthDay News) -- Being overweight at age 18, or obese at the time of breast cancer diagnosis, is correlated with an increased risk of breast cancer-related mortality, particularly in women with estrogen receptor-positive breast cancer, according to a study presented at ENDO 2011, the annual meeting of The Endocrine Society, held from June 4 to 7 in Boston.
Christina Dieli-Conwright, Ph.D., from the City of Hope National Medical Center in Duarte, Calif., and colleagues investigated the effect of obesity on breast cancer-related mortality in 3,995 female participants of the California Teachers Study, diagnosed with invasive breast cancer between 1995 and 2006. Body mass index (BMI) was calculated from the participants' self-reported height and weight at baseline and at age 18. A BMI of 30 kg/m² or higher was defined as obesity. The correlation between mortality risk and breast cancer estrogen-receptor status was also assessed.
The investigators found that, compared to nonobese women, women who were obese at baseline had a 69 percent higher risk of death due to cancer. Women who were overweight (BMI of 25 to 29 kg/m²) at age 18 had a similarly increased mortality risk. For women with estrogen receptor-positive cancer, the risk of breast cancer-related mortality increased with an increase in BMI. There was no correlation between breast cancer and mortality in women with estrogen-negative breast cancer.
"Obesity is strongly linked to death due to breast cancer. In particular, overweight or obese women with a history of estrogen receptor-positive breast cancer, but not those with estrogen receptor-negative cancer, had a higher risk of dying of their disease," Dieli-Conwright said in a statement.
Abstract No. P1-75 (subscription or payment may be required)