Elevated Iron Levels Associated With Metabolic Syndrome

Men and women with elevated levels of ferritin are about twice as likely as their peers with lower levels to have metabolic syndrome. Elevated levels of serum ferritin are tied to an increased prevalence of metabolic syndrome.

Senior author Dr. Eliseo Guallar, from Johns Hopkins University in Baltimore, stated that, "Previous studies have investigated the association between iron stores and the individual components of the metabolic syndrome, but. Our study is different in that it looked at the association with the whole syndrome and used a sample representative of the US population." The new study included 6044 adults who participated in the Third National Health and Nutrition Examination Survey. Metabolic syndrome was defined as the presence of three or more of the following: abdominal obesity, elevated plasma glucose, low HDL cholesterol, elevated serum triglycerides, and elevated blood pressure.

Men and women in the highest ferritin quartile were about twice as likely as their peers in lowest quartile to have metabolic syndrome. For example, the rates of metabolic syndrome in men with the highest and lowest levels were 27.3% and 13.8% (p < 0.001), respectively, and the corresponding rates in premenopausal women were 14.9% and 6.4% (p = 0.002).

The researchers also found that the prevalence of insulin resistance increased with each successive ferritin quartile.

As to how elevated iron stores may promote metabolic syndrome and insulin resistance, the authors note that excess iron may impair insulin extraction as well as insulin secretion. Moreover, Dr. Guallar was quick to add that these effects may occur with relatively normal iron levels as none of the subjects in the current study had the markedly high levels seen with hemochromatosis.

Diabetes Care 2004;27:2422-2428.