Unpacking the Predictors of Loneliness: An Inferential Analysis from the INTERACT Study

Background Loneliness is a pressing public health concern with wide-ranging impacts on mental, physical and social wellbeing. Building on the INTERACT Study-the largest UK-based investigation of loneliness-this paper explores demographic, social and health-related predictors of loneliness and social capital, using multiple validated measures. Methods We analysed cross-sectional data from 135,722 community-dwelling adults across England. Loneliness was assessed using both the UCLA 3-item Loneliness Scale and the ONS Direct Measure of Loneliness (DMOL). Social capital was measured using a composite scale of neighbourhood trust, cohesion and reciprocity. Multivariable ordinal logistic regression was used to examine predictors of loneliness; binary logistic regression was used to analyse correlates of high versus low social capital. Results Younger age (particularly 16–25), being single, unemployed or living with disability were consistently associated with higher loneliness across both scales. In contrast, greater social contact having nine or more friends or relatives was strongly protective (UCLA: aOR 0.09; DMOL: aOR 0.16). University education was associated with higher loneliness on the UCLA scale but lower loneliness on the DMOL. High social capital was more prevalent among older, married and retired individuals and strongly predicted lower loneliness. Respondents with long-term conditions or disability had reduced odds of high social capital (aORs 0.65 and 0.59 respectively). Conclusions This study highlights consistent sociodemographic and social predictors of loneliness, as well as the protective role of social capital. Findings support the need for targeted public health interventions that address social connection among young adults, single people, the unemployed and individuals in poor health. Strategies that invest in neighbourhood cohesion and social infrastructure are vital for mitigating loneliness and strengthening community wellbeing.