Iran survey links interpersonal social health to psychological distress and income inequality

A cross-sectional study published in BMC Public Health examined interpersonal social health among 18,754 adults aged 18 years or older in urban areas across all 31 Iranian provinces in 2025. Researchers used proportional, stratified, multistage cluster sampling and the validated 39-item Interpersonal Social Health Questionnaire. Multilevel mixed-effects models assessed associations with sociodemographic, psychological, and structural factors, accounting for clustering within counties and provinces.

The mean interpersonal social health score was 142.83 (SD 22.57; range 39–195). In the null model, intraclass correlations were 5.5% at the provincial level and 11.4% at the county level. Older age, female sex, marriage, higher education, employment, and higher socioeconomic status were associated with higher scores, although scores did not increase further in the highest socioeconomic quintile. Life and health satisfaction were positively associated with scores, while psychological distress was negatively associated.

Social hope was positively associated with interpersonal social health (standardized β = 0.04; p < 0.001), whereas provincial income inequality was negatively associated (standardized β = −0.10; p = 0.03). The positive association with social hope was weaker in provinces with greater inequality. These findings highlight the psychological and structural context of social health, but the cross-sectional design cannot establish causality. The urban study population also limits extrapolation to rural settings.