Prevalence of zinc deficiency and its clinical relevance among hospitalised elderly

Zinc is an essential trace element, and constituent of many metallo-enzymes required for normal metabolism. Age may be associated with altered metallo thionein metabolism related to changes in zinc metabolism. The objectives o f this study were: (i) to assess the prevalence of zinc deficiency among ho spitalised elderly patients; (ii) to define the social, functional, patholo gical and nutritional characteristics of zinc deficient elderly hospitalise d patients; and (iii) to assess the relationship between the zinc status an d humoral immune function among hospitalised elderly patients. Fifty consec utive patients underwent comprehensive geriatric assessments included evalu ations of the medical (index of the severity of the disease(s)), psychiatri c (Geriatric depression scale (GDS)), therapeutic, social, functional (Katz 's scale), and nutritional problems (Mini Nutritional Assessment (MNA) and biochemical markers (zinc, albumin, prealbumin (PAB), cholesterol) before t heir discharge. Fourteen patients (28%) presented a zinc concentrations low er than 10.7 mu mol/l, this value is usually considered as the cut-off leve l below which a zinc deficient status is possible, Higher proportions of re spiratory infections, cardiac failure, and depression were observed among z inc deficient patients as compared with the group of patients with normal z inc status. The other parameters of comprehensive geriatric assessment did not allow to discriminate the zinc deficient patients. The only slight diff erences (which remained unsignificant) concerned the prealbumin levels whic h tended to be higher in the group of patients presenting normal zinc statu s than in the group with poor zinc status (0.208 +/- 0.062 versus 0.171 +/- 0.068 g/l respectively, P = 0.06), and the IgG2 levels which tended to be lower in the group of patients with normal zinc status than in the group pr esenting poor zinc status (2.77 +/- 1.91 versus 4.06 +/- 2.56, respectively , P = 0.057). A negative correlation was observed between the Zn concentrat ions and the IgG2 levels (Spearman R = -0.311, P = 0.028). To the best of o ur knowledge, this is the first study presenting zinc status according to a comprehensive geriatric assessment among European hospitalised geriatric p atients. We decided to perform this study to known whom of our patients nee ded to be supplemented with zinc administration. Considering the low energy intake of hospitalised patients (confirmed here in regards of the nutritio nal assessment), and the insufficient trace element density in European foo ds, the relevance of providing medical supplements or enriched foods to thi s population has to be evaluated. Although most of the current diseases may be relevant to long-term interactions between nutrition and ageing, certai n states observed in the elderly, like impaired immune and cognitive functi ons, could still benefit from an appropriate nutritional supplementation. ( C) 2001 Elsevier Science Ireland Ltd. All rights reserved.