Lifestyle, Sleep, and Psychological Correlates of Social Participation Across Mediterranean and Neighbouring Countries: Findings from the MEDIET4ALL Survey

Background: Social participation is an important psychosocial dimension of health, but its associations with multiple lifestyle and psychological domains have rarely been examined simultaneously across Mediterranean and neighbouring countries. This study examined sociodemographic, health-related, Mediterranean dietary, movement-related, sleep-related, psychological, and technology-use correlates of social participation. Methods: Data were analysed from 4010 adults participating in the multinational MEDIET4ALL survey across ten countries. Social participation was assessed using the Short Social Participation Questionnaire (SSPQ). Hierarchical multiple linear regression examined associations across these domains, with the fully adjusted Model 6 designated as the primary inferential model. Sensitivity analyses examined sex- and region-related effect modification, country fixed effects, and categorical-variable coding. Exploratory indirect associations involving selected lifestyle behaviours and life satisfaction were estimated using bootstrapping. Results: The fully adjusted Model 6 explained 23% of the variance in social participation (adjusted R2 = 0.224). The largest standardized associations among the statistically supported correlates were observed for age (β = −0.224), anxiety (β = 0.194), life satisfaction (β = 0.160), physical activity (β = 0.152), and depression (β = −0.149). Dietary associations were generally comparable across sexes, but the positive association involving Mediterranean dietary habits was stronger among participants from Mediterranean countries (interaction p = 0.002). The principal associations were materially consistent in country fixed-effects and categorical-coding sensitivity analyses. Exploratory bootstrapped analyses identified statistically supported indirect associations through life satisfaction for both Mediterranean dietary dimensions and physical activity in relation to higher social participation and for sitting time in relation to lower social participation. Conclusions: Social participation was associated with multiple lifestyle, psychological, sleep-related, and sociodemographic domains within the MEDIET4ALL sample. These findings are associative, while the regional and indirect-association findings are exploratory and hypothesis-generating. Given the cross-sectional design, the results establish neither temporal nor causal relationships. Longitudinal and intervention studies are required to determine directionality and practical relevance.