Assessment of copper status: effect of age and gender on reference ranges in healthy adults.

We measured major indices related to copper nutritional status in 55 men and 86 women between ages 20 and 83 years who were in apparent good health. Plasma copper concentrations and both immunoreactive and enzymatically measured ceruloplasmin were significantly higher in women than in men and were higher in women taking oral contraceptives. Plasma copper, immunoreactive ceruloplasmin, and cytochrome-c oxidase in platelets and mononucleated leukocytes tended to increase with age. The ratio of enzymatic to immunoreactive ceruloplasmin, erythrocyte superoxide dismutase, and 67Cu uptake by erythrocytes were not significantly affected by either age or gender. Thus, factors other than copper nutriture--such as age, gender, and hormone use--need to be considered when using many of these indicators to evaluate copper nutritional status.