Immune function is impaired in iron-deficient, homebound, older women123

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ABSTRACT

Background

Aging is often associated with a dysregulation of immune function. Iron deficiency may further impair immunity in older adults. Published reports on iron deficiency and immune response in humans are inconsistent. Most studies are focused on young children in developing countries and are often confounded by comorbid conditions, infections, and nutrient deficiencies.

Objective

Our objective was to determine the relation of iron status with immune function in homebound older women, who often have impairments in both iron status and immune response. The subjects were selected according to rigorous exclusion criteria for disease, infection, and deficiencies in key nutrients known to affect immunocompetence.

Design

Seventy-two homebound elderly women provided blood for comprehensive evaluation of iron status and cell-mediated and innate immunity. Women were classified as iron-deficient or iron-sufficient on the basis of multiple abnormal iron status test results. Groups were compared with respect to lymphocyte subsets, phagocytosis, oxidative burst capacity, and T cell proliferation upon stimulation with mitogens.

Results

In iron-deficient women, T cell proliferation upon stimulation with concanavalin A and phytohemagglutinin A was only 40-50% of that in iron-sufficient women. Phagocytosis did not differ significantly between the 2 groups, but respiratory burst was significantly less (by 28%) in iron-deficient women than in iron-sufficient women.

Conclusions

Iron deficiency is associated with impairments in cell-mediated and innate immunity and may render older adults more vulnerable to infections. Further prospective studies using similar exclusion criteria for disease, infection, and concomitant nutrient deficiencies are needed for simultaneous examination of the effects of iron deficiency on immune response and morbidity.

Key Words

Iron status
cell-mediated immunity
phagocytosis
oxidative burst capacity
elderly women

Cited by (0)

1

From the Department of Nutritional Sciences (NA and JS), the Graduate Program in Nutrition (DK), the Department of Biochemistry and Molecular Biology (AM), and the University Health Services (GH), The Pennsylvania State University, University Park, PA.

2

Supported by research grants 96-35200-3132 and 2001-35200-10722 from the US Department of Agriculture and a grant from the National Cattlemen's Beef Association.

3

Reprints not available. Address correspondence to N Ahluwalia, S126 Henderson, Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802. E-mail: [email protected].