Fig. 1

Depressive symptoms (a1 to a3), anxiety symptoms, and sleep disturbances (b1 to b3) mediate the association between loneliness and its two components—personal feelings of isolation and the lack of relational connectedness—and cognitive function. The dotted arrows represent the direct and indirect effects of loneliness (the highest quartile with reference to the lowest quartile) and its two components (the high group with reference to the low group) on cognitive function. The values on the dotted arrows represent the multivariable-adjusted beta coefficients (95% confidence interval [95% CI]) of regression. * p < 0.05. The depressive symptoms, anxiety symptoms, and sleep disturbances were continuous variables. All models were adjusted for age, sex (male or female), education level (elementary or lower, junior high, senior high, and college or higher), current smoking (yes or no), current drinking (yes or no), sitting (h/d), walking for more than 10 min at least one day in the last week (yes or no), moderate or vigorous activity (yes or no), marital status (married or widowed, divorced, or unmarried), living status (living alone, living with one roommate, living with two roommates, living with three roommates), overweight (yes or no), number of comorbidities, and hearing impairment (yes or no)