Have Australians become more lonely and socially isolated? A longitudinal analysis of the Household, Income and Labour Dynamics in Australia study.

BACKGROUND: This study aimed to examine temporal trends in episodic and chronic loneliness and social isolation in the Australian population from 2001 to 2023. METHODS: We conducted a population-based longitudinal cohort study (n = 13 120). Data were drawn from the Household, Income and Labour Dynamics in Australia (HILDA) survey. Episodic (at least one wave) and chronic (at least two consecutive waves) loneliness and social isolation were assessed using validated measures. Mixed-effects logistic regression models estimated marginal predicted probabilities over time and across demographic subgroups. Sensitivity analyses were conducted to test the robustness of the findings. RESULTS: Loneliness remained relatively stable overall, with a slight early decline followed by a modest increase and a gradual rise in chronic loneliness from the late 2000s. In contrast, social isolation increased substantially over time, with chronic isolation roughly doubling across the study period. Loneliness trends generally followed a decline during the 2000s and a rise from the 2010s onwards across most demographic groups, although the magnitude and timing varied between subgroups. In contrast, social isolation increased over time across most populations, with particularly marked increases among older adults and individuals in the lowest education and highest area-level disadvantage. CONCLUSIONS: Social isolation increased substantially in Australia over the past two decades, while loneliness showed a moderate increase, disproportionately affecting vulnerable populations. Findings underscore the need for ongoing public health interventions that address the structural and social determinants of loneliness and social isolation.