Screen Time, Fatigue, Obesity and Physical Inactivity: Health Correlates of Problematic Smartphone Use in Adolescents.

OBJECTIVE: This study aimed to determine the prevalence of problematic smartphone use (PSU) among Tunisian adolescents, examine variations by sex and age and investigate associations with physical activity, fatigue and obesity while assessing the potential protective role of sports participation. METHODS: A cross-sectional study of 960 adolescents (53% female), aged 14-16 years utilized validated Arabic instruments including the Smartphone Addiction Scale-Short Version (SAS-SV), International Physical Activity Questionnaire (IPAQ-SF) and Fatigue Assessment Scale (FAS). Anthropometric measurements followed WHO protocols, and objective screen time data were collected from device tracking features. Statistical analyses included Mann-Whitney U tests, chi-square tests, Spearman's correlations and logistic regression models with sex stratification, all adjusted for multiple comparisons using Benjamini-Hochberg correction. RESULTS: PSU prevalence was 15.7%, with significantly higher rates in males (p < 0.001) and during mid-adolescence (p < 0.001). Adolescents with PSU showed substantially higher screen time (435 vs. 155 min/day, p < 0.001), reduced vigorous physical activity (0 vs. 480 MET-min/week, p < 0.001), increased obesity (12.6% vs. 0.7%, p < 0.001) and more severe fatigue (50.3% vs. 5.8%, p < 0.001). Sports participation demonstrated protective effects against PSU (OR = 0.4-0.6), with significantly stronger effects in females (interaction p = 0.03). CONCLUSION: PSU represents a significant public health concern among Tunisian adolescents, with a prevalence of 15.7% that is higher in males and mid-adolescents. It is associated with excessive screen time, inactivity, elevated BMI and fatigue, whereas sports participation offers a protective effect, particularly among girls.