How loneliness and sleep problems jointly shape mental health among middle-aged and older adults: a fixed-effects analysis

OBJECTIVES: Loneliness and sleep problems have each been linked to poorer mental health in later life, yet little is known about how they jointly shape well-being. This study is the first to examine whether multiple dimensions of sleep problems, including poorer sleep quality, more frequent use of sleep medication, greater sleep disturbance, greater daytime dysfunction, longer sleep latency, and short sleep duration, intensify the association between loneliness and mental health among adults aged 50 and older. METHOD: Data were drawn from two waves (2018-2020 and 2021-2023) of the UK Household Longitudinal Study, the only waves that simultaneously included measures of loneliness and sleep problems (19,398 person-years). Fixed-effects regression models were used to estimate within-person changes over time. RESULTS: Loneliness was associated with poorer mental health, and each dimension of sleep problems was independently linked to poorer mental health. The adverse association between loneliness and poorer mental health was amplified when individuals experienced higher levels of sleep problems across all six sleep dimensions examined. CONCLUSION: These findings highlight the importance of considering co-occurring stressors in later life. Interventions that address sleep health, alongside efforts to reduce loneliness, may offer a promising strategy for promoting mental well-being among aging populations.