High blood levels of iron coupled with high levels of very low density (VLDL) lipoprotein cholesterol appear to interact to increase the risk of cancer.

"Iron and lipids combine to create oxidative stress, and oxidative stress has a role in the development of cancer," Dr. Arch G. Mainous III, of the Medical University of South Carolina, Charleston, and colleague write in the American Journal of Epidemiology.

The researchers examined the risk of cancer among 3278 subjects in the Framingham Offspring Study who had elevated iron and lipid levels.

The participants were at least 30 years of age when they enrolled in the study between 1979 and 1982, at which point their blood levels of iron and HDL, LDL, and VLDL cholesterol were measured. They were followed up for development of cancer until 1996 to 1997.

The team reports that elevated iron increased the likelihood of developing cancer by 66 percent, and high VLDL cholesterol increased the risk by 54 percent. Combining elevated iron with elevated VLDL increased the risk of cancer by 168 percent.

High iron plus low HDL ("good") cholesterol also increased the risk to a similar degree.

"These findings support the hypothesis that iron-mediated oxidation of cholesterol increases oxidative stress, which can lead to cancer formation," Mainous and colleagues conclude.

Assuming the finding is confirmed by others, they say, it suggests a need "to reduce iron and/or lipid levels in persons with dual elevations in these substance as a strategy to decrease cancer risk."

SOURCE: American Journal of Epidemiology, June 15, 2005.