WASHINGTON -- Overweight women with low levels of the so-called good cholesterol seem to have a higher risk of postmenopausal breast cancer, Norwegian researchers reported yesterday.
That doesn't mean HDL cholesterol, which protects against heart disease, plays an active role in cancer. But it might signal which women harbor excess hormones, androgens, which are linked to breast cancer but are hard to measure, concluded researchers from Norway's University of Tromso.
Their study, published in the Journal of the National Cancer Institute, analyzed data from a registry that tracked the health of nearly 39,000 women for two decades.
It found no relationship between total cholesterol and breast cancer. But overweight women with the highest levels of HDL cholesterol were almost one-third less likely to get postmenopausal breast cancer than similar women with low HDL.
The study is very preliminary and doesn't change health recommendations for women, stressed American Cancer Society epidemiologist Eugenia Calle.
Doctors have long known that being overweight after menopause increases breast cancer risk, Calle said. As for heart health, research shows that exercise, losing weight, quitting smoking, and modest drinking may help nudge up those HDL levels.
Excess androgens -- male sex hormones, including testosterone -- also are associated with increased breast cancer risk. The Norwegian researchers cite evidence that androgens can lower HDL levels, arguing that the easier-to-measure cholesterol could help identify women at risk.
But that remains an unproven theory, emphasized Calle of the cancer society. She noted that low HDL occurs in normal-weight women, too, yet the Norwegian study found a cancer link only among the overweight.