Having diabetes or being obese after age 60 significantly increases the risk for developing breast cancer, a Swedish study has revealed. Data also showed that high blood lipids were less common in patients when diagnosed with breast cancer, while low blood lipids were associated with an increased risk.
Researchers of the study also looked at overall cancer incidence and discovered that use of one diabetes drug was associated with a lower rate of any cancer, while another was associated with an increased risk.
Researchers evaluated health care data from a region of 1.5 million people living in Southwestern Sweden to provide a comprehensive picture of cancer risk.
Olsson H and his colleagues at Lund University, examined records of 2,724 patients up to 10 years before they developed cancer and 20,542 patients who never developed the disease.
They found that obesity in women after age 60 increased risk for developing breast cancer by 55%. At the most, 15 out of 100 obese women would get breast cancer compared with slightly less than 10 out of 100 in the general population.
Women with diabetes had a 37% increased risk for developing breast cancer if their diabetes had been diagnosed up to four years before cancer was diagnosed.
Women with abnormally low levels of blood lipids ( mostly cholesterol ) had a 25% greater risk for developing breast cancer, while high levels of blood lipids appeared to be associated with a lower risk for breast cancer. The mechanisms behind these effects are unclear, and the finding needs to be replicated in a different population-based study.
Researchers also looked at the national drug prescription registry to examine the link between risk for all cancers and use of two diabetes drugs, Insulin Glargine ( Lantus ) and Metformin.
In this study, investigators found that Lantus use, which had been associated with increased cancer development in previous European studies, almost doubled the risk for development of any cancer, while Metformin was linked to an 8% lower risk for cancer in patients with diabetes.
According to investigators more research is needed to clarify the specific cancers at increased risk. The number of patients in this study who developed breast cancer using these medications was too small to make any link to breast cancer risk.
Source: San Antonio Breast Cancer Symposium, 2011
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