Análise fatorial do índice de qualidade de sono de pittsburgh (Psqi) e sua correlação com componentes da composição corporal de adolescentes

Objectives: Investigate the factorial structure of the Pittsburgh Sleep Quality Index (PSQI) componentes, and whether age, sex, body mass index, and body fat percentage are related to PSQI global score and the factors found through the factorial analysis. Methods: A cross-sectional study was performed with 217 institutionalized adolescents between 14-19 years old. Body composition parameters and sleep quality (PSQI) were measured. Results: Confirmatory factorial analysis of PSQI components confirmed that a two-factor model explained 57.4% of the variance. Differences between sexes were observed in the global PSQI score (9.5±2.3 vs. 10.5±2.2; p=0.002) and Perceived Sleep Quality (PSQ) (8.1±1.9 vs. 9.1±2.0; p=0.000). Age is positively related with the scores of all factors only in boys [i.e. global PSQI (r=0.20; p=0.023), PSQ (r=0.18; p=0.040) and Sleep Efficiency (SE) (r=0.25; p=0.006)], while body composition parameters were not associated with any of the scores. Conclusion: The two-factor model, with the exclusion of component 6 showed internal consistency and moderate reliability. Furthermore, there were observed differences between the sexes in relation to PSQI global score and PSQ but not to SE. The correlation analyses demonstrated that, among boys, the age was positively correlated with the different types of sleep quality scores.