Qualidade e duração do sono e a síndrome metabólica: um estudo de associação

Abstract

INTRODUCTION: Metabolic Syndrome (MS) is a complex disorder, characterized by cardiovascular risk factors, related to the simultaneous impairment of metabolic and vascular functions and central obesity. However, other mechanisms appear to be related to MS, such as sleep disorders, which appear to interrupt essential homeostatic processes. Therefore, this study aims to investigate the association between sleep quality and MS and its associated factors. METHODS: this is a cross-sectional study, with 166 adult and elderly individuals, of both sexes, attended at the Center for Research and Extension in Nutritional Genomics and Metabolic Dysfunctions (GENUT/UNEB). The diagnosis of MS was defined according to criteria proposed by the International Diabetes Federation (IDF, 2006) and the qualitative and quantitative assessment of sleep, based on the application of the Pittsburgh Sleep Quality Index (PSQI). Sleep duration was categorized as: short, <6 hours per night; adequate, 6-8 hours per night and long, >8 hours per night. Data were analyzed using Stata software (version 12.0). The Chi-Square test or Fisher's exact test were used to identify associations between nominal variables, and the Student's t-test, Mann-Whitney or Kruskal-Wallis test for quantitative variables. To evaluate the correlation coefficient between non-parametric variables, Spearman's coefficient was applied. The significance level established was 5%. This project was approved by the UNEB Research Ethics committee, CAEE: 03409712.9.3001.5023. RESULTS: Data from 166 individuals were investigated, 116 with MS and 50 without MS. No association was found between sleep quality (p=0.357) and duration (p=0.159) and MS. However, in alcoholic individuals, there was an association between poor sleep quality and low HDL-c (p= 0.005) and between adequate sleep duration and hypertriglyceridemia (p=0.045). A moderate, inverse and statistically significant relationship was also observed between sleep duration and quality (p= 0.000). Furthermore, a 63% lower chance of alcoholics having MS was observed, compared to non-drinkers. Age was considered a risk factor for MS and white skin color/race was a protective factor. The majority of participants reported adequate sleep duration (62.05%), which can be explained by the sociodemographic characteristics of the studied population. CONCLUSION: In this study, no association was found between sleep quality and duration with MS, which can be explained by the heterogeneity of the types of study, the populations studied, the MS classification criteria and the collection of sleep data. The results obtained reinforce the relevance of alcoholism as a modifying factor in this relationship. Additional studies are needed to investigate the role of sleep in MS, and above all, the dose-response effect of alcohol consumption on sleep.