Background

Excessive screen exposure and inadequate sleep are increasingly common behaviours that may contribute to adult obesity through sedentary time, altered energy intake, and metabolic dysregulation. This study assessed the independent and combined associations of daily screen time and habitual sleep duration with body mass index (BMI) among adults.

Methods

This community-based cross-sectional study included 308 adults aged 18–60 years selected through systematic random sampling. Sociodemographic characteristics, screen exposure, habitual sleep duration, physical activity, dietary practices, and clinical history were recorded using a structured questionnaire. Height and weight were measured using standard procedures, and BMI was classified according to Asian adult thresholds. Group differences were examined using the independent-samples t test, one-way ANOVA, and chi-square test. Spearman’s correlation and multiple linear regression were used to identify independent relationships with BMI.

Results

The mean age was 37.9±11.5 years, 53.6% were male, and 47.7% had BMI ≥23 kg/m². Mean BMI increased from 21.9±3.3 kg/m² among participants reporting <2 hours/day of screen time to 25.6±4.0 kg/m² among those reporting ≥6 hours/day (p<0.001); obesity increased from 11.8% to 42.9% (p=0.003). Short sleepers had higher mean BMI than those sleeping 7–9 hours (25.2±4.0 versus 23.0±3.7 kg/m²) and a higher prevalence of obesity (40.6% versus 16.5%; both p<0.001). Screen time correlated positively with BMI (r=0.34), whereas sleep duration correlated inversely (r=−0.23; both p<0.001). Each additional hour of screen time was associated with a 0.30 kg/m² increase in BMI, while short sleep was associated with a 0.91 kg/m² higher BMI after adjustment. Participants with screen time ≥4 hours and sleep <7 hours had 5.63-fold higher crude odds of BMI ≥23 kg/m².

Conclusion

Higher screen exposure and short sleep were independently and jointly associated with greater BMI. Adult obesity-prevention strategies should integrate screen reduction, adequate sleep, increased physical activity, and interruption of prolonged sedentary periods.