EFFECTS OF SHORT-TERM ZINC SUPPLEMENTATION ON CELLULAR-IMMUNITY, RESPIRATORY SYMPTOMS, AND GROWTH OF MALNOURISHED EQUADORIAN CHILDREN

Objective: To assess the effect of zinc supplementation on respiratory tract disease, immunity and growth in malnourished children. Design: A randomized double-blind placebo-controlled trial. Setting: A day-car e center in Quite, Ecuador. Subjects: Fifty children (12-59 months old ) recruited by height-for-age and weight-for-age deficit. Intervention s: Twenty-five children (supplemented, S group) received 10 mg/day of zinc as zinc sulfate, and 25 (nonsupplemented, NS group) received a pl acebo during 60 days. All were also observed during a 60-day postsuppl ementation period. Two children of the S group dropped out. Daily the clinical presence of cough, respiratory tract secretions, and fever, w as recorded. On days 0, 60 and 120, the cutaneous delayed-type hyperse nsitivity (DTH) to multiple antigens, and anthropometric parameters we re assessed. On days 0 and 60 serum zinc levels were also measured. Re sults: On day 60, DTH was significantly larger (20.8 +/- 7.1 vs 16.1 /- 9.7 mm), and serum zinc levels were significantly higher (118.6 +/- 47.1 vs 83.1 +/- 24.5 mu g/dl) in the S group than in the NS group (P < 0.05 for each). The incidence of fever [relative risk (RR)I 0.30, c .i. = 0.08-0.95, P = 0.02], cough (RR): 0.52, c.i. = 0.32-0.84, P = 0. 004) and upper respiratory tract secretions (RR):0.72, c.i. = 0.59-0.8 8, P = 0.001) was lower in the S group than in the NS group at day 60. At the end of the postsupplementation observation period (day 120), t he incidence of fever and upper respiratory tract secretions was the s ame in both the S and NS groups. The incidence of cough was higher at day 120 in the S group than in the NS group (RR): 2.28, c.i. = 1.37-3. 83, P = 0.001). Conclusions: This study supports a role for zinc in im munity, and immunity to respiratory infections, while pointing out the need for larger studies.