Avaliação de zinco no plasma e correlação com marcadores metabólicos e da síndrome metabólica em relação aos fatores associados em idosos institucionalizados de Natal-RN

Abstract

Aging can lead to several biopsychosocial changes, which make elderly individuals vulnerable to metabolic and nutritional disorders, such as zinc deficiency and metabolic syndrome (MS). The aim of this study was to evaluate plasma zinc and the correlation with metabolic markers and the frequency of MS in relation to the associated factors in institutionalized elderly individuals. Cross-sectional study involving elderly individuals enrolled in nine nursing homes (NH) was carried out. In study 1, on plasma zinc and correlation with metabolic markers, 255 individuals participated. It was evaluated the zinc plasma concentrations and the associations with dietary zinc, as well as sociodemographic indicators and glycemic, lipid and inflammatory profile biomarkers were evaluated. Independent variables were analyzed according to quartiles of plasma zinc concentrations (µg/dL) (Q1: <71.1; Q2: 71.1-83.3; Q3: <83.3-93.7; Q4: >93.7). The correlation between plasma zinc concentration and predictor variables was also tested. In Q1, higher concentrations of the following variables were observed, compared with those in other quartiles: total cholesterol and LDL-c (Q1> Q2, Q3, Q4, all p <0.001); triacylglycerols (Q1> Q3, Q4, all p <0.001); IL-6 (Q1> Q3, Q4, p = 0.024 and p = 0.010, respectively); and TNF-α (Q1> Q3, p = 0.003). A significant reduction in plasma zinc concentrations was observed with increasing age-adjusted institutionalization time (Δ= -0.10; CI95%: - 0.18,-0.01), and concentrations of total cholesterol (Δ= -0.19; CI95%:- 0.23,-0.15), LDL-c (Δ= -0.19; CI95%: -0.23,-0.15), triacylglycerols (Δ= -0.11; CI95%: -0.16,-0.06), IL-6 (Δ= -1.41; CI95%: -2.64,-0.18) and TNF-α (Δ= -1.04; CI95%: -1.71,-0.36). Thus, data from the present study suggest that decreased plasma zinc concentration is associated with longer institutionalization time, and changes in the lipid and inflammatory profile in institutionalized elderly individuals. In study 2, on the MS frequency and relationship with associated factors, 202 individuals were included. MS frequency was assessed according to the criteria of the National Cholesterol Education Program - Adult Treatment Panel III. The association of MS with sociodemographic, clinical, dietary and lifestyle factors was analyzed. MS frequency was 29.2% (95% CI: 23.0-36.0%). Factors associated with MS were female sex (prevalence ratio [PR] = 2.16, 95% confidence interval [CI], 1.04-4.49), institutionalization time adjusted for age> 50% (PR = 2.31, 95% CI, 1.46-3.88), and high concentrations of IL-6 (RP = 2.01, 95% CI, 1.21-3.32) and TNF-α, 70, 95% CI, 1.05-2.77). In addition, it was found that the occurrence of MS was 1.85-fold higher (95% CI, 1.11-3.10) in the group with diet characterized as of very high energy, very low fat and high fiber intake, according to factorial analysis model. Thus, the results point to a moderate MS frequency, which was associated with female sex, longer age-adjusted institutionalization time, immunological changes, as well as a higher dietary energy and fiber intake and a lower dietary total fat intake.