Predictors of plasma zinc concentrations in children with acute diarrhea.

BACKGROUND Plasma and serum zinc concentrations are the most widely used markers of zinc status in individual persons and populations. OBJECTIVE The objective was to identify factors that influence plasma zinc concentrations during acute childhood diarrhea. DESIGN This was a cross-sectional study of 1757 cases of acute diarrhea in 6-35-mo-old Nepalese children. The association between plasma zinc concentration and several clinical, anthropometric, socioeconomic, and biochemical variables was estimated in simple and multiple linear regression analyses. RESULTS We observed a reduction in the mean plasma zinc concentration of 0.59 (95% CI: 0.44, 0.74) micro mol/L per degree ( degrees C) increase in axillary temperature. Having dysentery and an elevated plasma C-reactive protein concentration was also independently associated with lower plasma zinc. Children with clinical features of dehydration had higher plasma zinc concentrations than did those who were not dehydrated. Furthermore, a decrease in plasma albumin of 1 g/L was associated with a decrease in plasma zinc of 0.25 (95% CI: 0.21, 0.29) micro mol/L. The plasma albumin concentration confounded the associations between some clinical variables and plasma zinc, but the association between axillary temperature and dehydration on one hand and plasma zinc on the other was not substantially influenced by the albumin concentration. Moreover, the plasma zinc concentration increased with an increase in observed hemolysis. CONCLUSIONS Dehydration, clinical and biochemical indicators of inflammation and hemolysis, and, when possible, plasma albumin concentrations should be taken into account when the plasma zinc concentration is used to estimate zinc status during episodes of diarrhea in childhood.