Insulin‐Like Growth Factor‐I in Human Malnutrition: Relationship with Some Body Composition and Nutritional Parameters

Abstract

The insulin-like growth factor-I (IGF-I) plasma concentration was evaluated as a nutritional parameter in 18 patients affected with chronic malnutrition secondary to biliopancreatic bypass and compared with albumin, transferrin, and with body composition parameters: total body water (TBW), total body sodium (TBNa), total body potassium (TBK). Subjects were studied in malnutritional conditions and after 20 to 30 days of parenteral and enteral refeeding treatment. Immunoreactive IGF-I concentration was 0.35 U/ml +/- 0.07 (mean +/- SEM), significantly lower (p less than 0.01) than in age-matched controls (1.14 +/- 0.07 U/ml, n = 29) and rose significantly (0.84 +/- 0.12 U/ml; p less than 0.01) in parallel with the improvement of nutritional status. The ratios TBNa/TBW, TBNa/TBK, and TBK/TBW were then considered as reference parameters for definition of malnutritional state, and compared with IGF-I as well as with the most commonly used parameters, albumin and transferrin. Before treatment, IGF-I evidenced higher specificity (true negative ratios 0.63, 0.43, and 0.40 with regard to TBNa/TBW, TBNa/TBK, and TBK/TBW, respectively) than albumin (0.13, 0.14, and 0.10) and transferrin (0 in all cases), and slightly less sensitivity (true positive ratios for IGF-I 0.80, 0.67, and 0.67; always one for albumin and transferrin). Moreover, IGF-I resulted definitely more sensitive in assessing the effectiveness of the refeeding treatment and, on the basis of the likelihood ratio, it appeared a good discriminator of the nutritional status. The data indicate that different nutritional factors regulate IGF-I, albumin, and transferrin, and suggest that IGF-I can be used as a reliable and specific nutritional parameter, complementary to the others currently used.