Salivary indicators of protein nutritional status in the elderly

Protein-energy malnutrition (PEM) is a serious nutritional problem in hospi talized elderly patients. Serum albumin, transthyretin (prealbumin), and to tal protein have been used as biochemical indicators of protein nutritional status, but taking blood from the elderly is difficult and invasive. We th erefore assessed the possibility of using saliva or urine as noninvasive ma terials to estimate serum concentrations of albumin, transthyretin and tota l protein. Blood, saliva and urine were collected from 32 hospitalized elde rly (aged 68-97 y) and the correlation between the concentrations of albumi n, transthyretin and total protein in serum and those in saliva or urine we re evaluated. There was no correlation among them, but the concentrations o f albumin and transthyretin adjusted for the concentration of IgG in saliva were significantly correlated with the concentrations of albumin and trans thyretin in serum (albumin: R-2 = 0.308, p = 0.0010, transthyretin: R-2 = 0 .433, p < 0.0001 by log linear regression analysis). This study suggests th e possible usefulness of the concentrations of proteins in the fluids for e valuating protein nutritional status in the elderly. Further studies on the method of adjustment of protein concentrations in saliva and the adaptabil ity to other populations will confirm the results of this study. (C) 1999 E lsevier Science Inc.