Simin N Meydani, Junaidah B Barnett, Gerard E Dallal, Basil C Fine, Paul F Jacques, Lynette S Leka and Davidson H Hamer

1 From the Nutritional Immunology Laboratory (SNM, JBB, LSL, and DHH), the Biostatistics Unit (GED), and the Nutritional Epidemiology Program (PJF), Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA; the Department of Pathology, Sackler Graduate School of Biochemical Sciences, Tufts University, Boston, MA (SNM); the Friedman School of Nutrition Science and Policy at Tufts University (SNM, JBB, GED, PFJ, and DHH); the Nutrition/Infection Unit, Department of Public Health and Family Medicine, Tufts University School of Medicine, Boston, MA (JBB); the Travel and Tropical Medicine Practice, Boston, MA (BCF); the Department of Medicine, Boston University School of Medicine, Boston, MA (DHH); and the Center for International Health and Development, Boston University School of Public Health, Boston, MA (DHH)

Background: Zinc plays an important role in immune function. The association between serum zinc and pneumonia in the elderly has not been studied.

Objective: The objective was to determine whether serum zinc concentrations in nursing home elderly are associated with the incidence and duration of pneumonia, total and duration of antibiotic use, and pneumonia-associated and all-cause mortality.

Design: This observational study was conducted in residents from 33 nursing homes in Boston, MA, who participated in a 1-y randomized, double-blind, and placebo-controlled vitamin E supplementation trial; all were given daily doses of 50% of the recommended dietary allowance of essential vitamins and minerals, including zinc. Participants with baseline (n = 578) or final (n = 420) serum zinc concentrations were categorized as having low (<70 µg/dL) or normal serum zinc concentrations. Outcome measures included the incidence and number of days with pneumonia, number of new antibiotic prescriptions, days of antibiotic use, death due to pneumonia, and all-cause mortality.

Results: Compared with subjects with low zinc concentrations, subjects with normal final serum zinc concentrations had a lower incidence of pneumonia, fewer (by almost 50%) new antibiotic prescriptions, a shorter duration of pneumonia, and fewer days of antibiotic use. Normal baseline serum zinc concentrations were associated with a reduction in all-cause mortality (P = 0.049).

Conclusion: Normal serum zinc concentrations in nursing home elderly are associated with a decreased incidence and duration of pneumonia, a decreased number of new antibiotic prescriptions, and a decrease in the days of antibiotic use. Zinc supplementation to maintain normal serum zinc concentrations in the elderly may help reduce the incidence of pneumonia and associated morbidity.