Influência do estado nutricional sobre a estabilidade osmótica de eritrócitos de idosos institucionalizados

Abstract

Introduction: Aging is a natural process characterized by a gradual and irreversible loss of organic functions. The increased morbidity and mortality of elderly people is directly related to malnutrition, a condition that has a major impact on the rheological properties and functions of the blood. Objective: This study aimed to evaluate the correlations between nutritional status, age, anthropometric, biochemical and hematological variables, and osmotic stability of erythrocytes in a population of 69 institutionalized elderly. Methods: The erythrocyte osmotic stability was measured by the variable 1/H50, which is the inverse of the salt concentration at the midpoint of the osmotic haemolysis curve and by the variable dX, which represents the variation of the concentration of salt required to promote total osmotic haemolysis. The Mini Nutritional Assessment (MNA) was used to assess the nutritional status (nourished, at risk of malnutrition and malnourished). The existence of an association between variables was assessed using Pearson correlation. Search for indirect effects between variables was made by path analysis. Results: The majority of the study population was at risk of malnutrition or malnourished. The body mass index (BMI) and the stability variable dX showed significant positive correlations with the MNA scores. Path analysis showed the existence of inverse indirect effects, mediated by the BMI and the MNA scores, between age and dX. Conclusion: The indirect decrease in osmotic stability of erythrocytes with increasing age observed in this study does not represent a true age-dependent process, but a consequence of worsening of the nutritional status of the study participants with increasing age.