Does context of physical activity moderate the association between screen time and positive mental health?

Background: Screens are omnipresent and can have adverse effects on mental health. Outdoor physical activity (OPA) and group physical activity (GPA) have numerous benefits on mental health. Whether they could buffer the screen time- mental health negative associations remain unknown.

Purpose: To estimate the association between occupational and recreational ST and positive mental health (PMH) in adults, and test whether GPA or OPA moderates this association.

Methods: Data from the longitudinal NDIT Study are used (n = 623, mean (SD) age = 35.2 (0.6) yrs). The mean amount of hours/day of ST was measured for occupational and recreational contexts. PMH was measured six months later using the Mental Health Continuum-Short Form. The monthly frequency of GPA and OPA was measured using a 6-point Likert scale. Multivariable linear regressions were estimated adjusting for sex, age, education level, and PA volume; moderation was investigated by adding an interaction term (ST*GPA or ST*OPA). Stratified analyses were then conducted to compare frequent and infrequent OPA and GPA subgroups.

Results: Adjusted models suggest a negative association for occupational ST (B[95%CI] = -0.3[-0.6, -0.0]) and recreational ST (-1.1[-1.6, -0.7]) and PMH. Adjusted stratified analyses show a lower negative association between occupational ST and PMH in the frequent OPA group (-0.1[-0.5; 0.2]) compared to the infrequent OPA group (-0.6[-1.2; -0.0]). In the context of occupational ST, similar findings were observed for GPA. A similar pattern of results also occurred for recreational ST.

Conclusion: The results suggest a negative association between different contexts of ST and PMH in adults. Frequent OPA and GPA could moderate these associations.

Practical implications: The moderating effect of GPA and OPA provides a promising avenue for intervention. Further investigations using longitudinal study designs with larger samples are needed.

Funding : Réseau de recherche en santé des populations du Québec.