Effect of loneliness on health and mortality in Australia

Loneliness is an important public health issue with potentially detrimental effects on physical and mental health and an increased risk of early death. This study emulates a target trial using longitudinal data from a population-representative cohort of Australian adults to estimate the effect of loneliness and social isolation on subsequent all-cause mortality. By leveraging repeated measurements across survey waves, we define four time-varying exposure states—neither lonely nor socially isolated, loneliness only, social isolation only, and both lonely and socially isolated—and assess whether sustained or episodic exposures confer a greater mortality risk.