Women with type 2 diabetes usually have low HDL-C, increasing risk for breast cancer.
Low-levels of high-density lipoprotein cholesterol (HDL-C), as a component of the metabolic syndrome, may serve as a marker of breast cancer risk in postmenopausal women, research suggests.
The prevalence of the metabolic syndrome, which is characterized by obesity, glucose intolerance, low serum HDL-C, high serum triglycerides and hypertension, "is high and increasing in parallel with breast cancer incidence worldwide," investigators note in the August 4th Journal of the National Cancer Institute.
While HDL-C is "an important aspect of the syndrome," its role in breast cancer remains undefined, Dr. Anne-Sofie Furberg from the University of Tromso in Norway and colleagues write.
To investigate, they analyzed data from a Norwegian cohort of nearly 39,000 women who provided lipid, weight, diet, and lifestyle data at baseline and throughout the study. A total of 708 women developed invasive breast cancer during a median of 17.2 years of follow up.
In multivariate analysis, low HDL-C was independently associated with an increased risk of postmenopausal breast cancer in overweight and obese women.
According to Dr. Furberg, "when the overweight and obese women were divided in four equalized subgroups according to increasing levels of HDL-C in the blood, women with the lowest level of HDL-C had a threefold higher risk of postmenopausal breast cancer as compared to women with the highest level of HDL-C."
"These findings suggest an interaction between metabolic disturbances (i.e., overweight or obesity and lower serum HDL-C) in postmenopausal breast carcinogenesis," the authors write.
Dr. Furberg emphasized that "the observed association between low HDL-C and increased postmenopausal breast cancer risk in overweight and obese women needs to be confirmed in studies of other populations to verify the role of HDL-C as a useful maker in clinical practice."
J Natl Cancer Inst 2004;96:1152-1160.