Résumé
Objectives:. Feeling lonely is associated with worse health as people get older, yet its relation to physical function is unclear. This study examined the association between loneliness and performance-based measures of physical function. Methods:. Participants (age range: 34-103 years; N > 33,000) were from six established cohorts: Five were from the United States and one was from the United Kingdom. Participants were assessed on loneliness, demographic factors, disease burden, physical inactivity, gait speed, grip strength, lower limb strength, and standing balance. Results:. Higher loneliness was associated with a higher likelihood of slow gait speed (k = 6; pooled odds ratio [OR] = 1.25; 95% CI= 1.16;1.35, p < 0.001), weak grip strength (k = 5; OR= 1.19; 95% CI= 1.09;1.30, p < 0.001), weak lower limb strength (k = 5; OR= 1.19; 95% CI= 1.13;1.27, p < 0.001), and balance impairment (k = 3; OR= 1.29; 95% CI= 1.23;1.36, p < 0.001). These associations were independent of disease burden and physical inactivity. There was little consistent evidence that sociodemographic factors moderated these associations. Conclusion: The present study provides replicable evidence that loneliness is associated with worse performance across multiple domains of physical function.