Damir Knjaz

Associations between sleep quality and its domains and insufficient physical activity in a large sample of Croatian young adults: a cross-sectional study

Objectives The main purpose of the present study was to explore the associations between sleep quality and insufficient physical activity. Design Cross-sectional. Setting Faculties in Croatia. Participants 2100 university students (1049 men and 1051 women) aged 18–24 years were recruited. Primary outcome To assess the domains of sleep quality (independent variables) and ‘insufficient’ physical activity (dependent variable), we used previously validated Pittsburgh Sleep Quality Index and International Physical Activity questionnaires. Logistic regressions were used to calculate the associations between the sleep quality and ‘insufficient’ physical activity. Results When sleep quality domains were entered separately into the model, very bad subjective sleep quality (OR 3.09; 95% CI 1.50 to 6.56), >60 min of sleep latency (OR 2.17; 95% CI 1.39 to 3.39), <7 hours of sleep (OR 1.56; 95% CI 1.24 to 1.96), <65% of habitual sleep efficiency (OR 2.26; 95% CI 1.26 to 4.05), sleep disturbances >1/week (OR 1.61; 95% CI 1.03 to 2.52), use of sleep medication >1/week (OR 3.35; 95% CI 1.83 to 6.10), very big daytime dysfunction problem (OR 2.78; 95% CI 1.57 to 4.93) and poor sleep quality (1.53; 95% CI 1.23 to 1.91) were associated with ‘insufficient’ physical activity. When all sleep quality domains were entered simultaneously into the model, the same significant associations remained, except for sleep disturbances. Both models were adjusted for gender, body mass index, self-rated health, life satisfaction, socioeconomic status, presence or absence of chronic diseases, smoking status, binge drinking and psychological distress. Conclusions Our results show that ‘poor’ sleep quality is associated with ‘insufficient’ physical activity in young adults. In order to improve, special strategies and policies that leverage ‘good sleep’ quality are warranted.