Living arrangement modifies the associations of loneliness with adverse health outcomes in older adults: evidence from the CLHLS

BACKGROUND: Although it has been suggested that loneliness is a risk factor for adverse health outcomes, living arrangement may confound the association. This study aimed to investigate whether the associations of loneliness with adverse health outcomes differ in community-dwelling older adults according to different living arrangements. METHODS: In the 2008/2009 wave of Chinese Longitudinal Healthy Longevity Survey, 13,738 community-dwelling older adults (≥65 years) were included for analyses. Living arrangements and loneliness were assessed. Health outcomes including cognitive and physical functions were assessed using MMSE, ADL/IADL scales and Frailty Index in the 2008/2009 and 2011/2012 waves; mortality was assessed in the 3-year follow-up from 2008/2009 to 2011/2012. The effect modificaitons of loneliness on adverse health outcomes by living arrangements were estimated using logistic regression or Cox proportional hazards regression models. RESULTS: Living alone older adults were significantly more likely to be lonely at baseline (52% vs 29.5%, OR = 1.90, 95% CI = 1.67–2.16, P < 0.001), compared with those living with others. Loneliness in older adults was a significant risk factor for prevalent cognitive impairment and frailty, and 3-year mortality, especially among those who lived with others (OR = 1.32, 95% CI = 1.15–1.52, P < 0.001; OR = 1.39, 95% CI = 1.24–1.57, P < 0.001; HR = 1.14, 95% CI = 1.05–1.24, P = 0.002, respectively). In contrast, among the living alone older adults, loneliness was only significantly associated with higher prevalence of frailty (OR = 1.42, 95% CI = 1.07–1.90, P = 0.017). Living arrangement significantly modified the associations of loneliness with prevalent cognitive impairment and 3-year mortality (P values for interaction = 0.005 and 0.026, respectively). CONCLUSIONS: Living arrangement modifies the associations of loneliness with adverse health outcomes in community-dwelling older adults, and those who lived with others but felt lonely had worse cognitive and physical functions as well as higher mortality. Special attention should be paid to this population and more social services should be developed to reduce adverse health outcomes, in order to improve their quality of life and promote successful aging. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-021-02742-5.