Low Serum Zinc Levels and Associated Risk Factors in Hospitalized Patients Receiving Oral or Enteral Nutrition: A Case-control Study

Purpose: To assess whether hospitalization and feeding strategy impact the risk of hypozincemia and associated risk factors. Methods: In this case-control study, serum zinc levels were compared between inpatients fed oral nutrition (ON) (n = 76) or enteral nutrition (EN) (n = 191) with outpatient controls (n = 1095). Findings: Zinc levels were significantly lower in inpatients receiving EN compared with those receiving ON (P = 0.001). Significant (P < 0.001) beta-values of -11.16 and -17.58 for serum zinc concentrations were found for inpatients receiving ON or EN, respectively, compared with the outpatients. Hospitalization and old age were both independent predictors of zinc deficiency. More than 75% of patients >60 years of age fed EN had a zinc concentration <68.75 mu g/dL. Low hemoglobin levels increased the risk of low zinc levels for inpatients receiving EN (P = 0.003) and ON (P = 0.026). Age (P < 0.001), noninvasive mechanical ventilatory support (P = 0.016), and critical care (P = 0.018) were risk factors for hypozincemia in patients receiving ON. Low iron levels were associated with hypozincemia (P = 0.001) in patients receiving EN. (C) 2020 Elsevier Inc.