Associations of Social Support, Loneliness, and Physical Activity with Cognitive Function in Older Adults with Mild...

Objectives: This study investigated how perceived social support, loneliness, and physical activity are related to cognitive performance among older adults with mild cognitive impairment. Methods: This cross-sectional investigation included 112 community-dwelling older adults with mild cognitive impairment. Perceived social support, loneliness, and physical activity were evaluated with the Multidimensional Scale of Perceived Social Support (MSPSS), UCLA Loneliness Scale, and International Physical Activity Questionnaire (IPAQ), respectively. Cognitive functioning was characterized through a battery comprising the Montreal Cognitive Assessment (MoCA), Isaac Set Test, Trail Making Test Parts A and B (TMT-A and TMT-B), Digit Symbol Substitution Test (DSST), and d2 Attention Test. Relationships among the study variables were examined through correlation and multivariable linear regression analyses, with age, sex, and educational level included as covariates. To address multiplicity, Benjamini-Hochberg false discovery rate (FDR) adjustment was conducted independently for the predefined families of correlations, main-effect regression coefficients, and interaction terms. Results: Significant bivariate relationships with cognitive performance were observed for perceived social support, loneliness, and physical activity, with all 18 correlations retaining significance following FDR adjustment. After covariate adjustment, 12 of the 36 main-effect coefficients met the FDR-corrected significance threshold. Among the factors examined, physical activity displayed the broadest pattern of independent associations, encompassing global cognition, visual attention and processing speed, executive function, processing speed, and selective attention and concentration. Perceived social support was independently related to global cognition, visual attention and processing speed, and executive function. In contrast, five effects that reached nominal significance did not withstand FDR adjustment; these included physical activity in relation to verbal fluency and loneliness in relation to global cognition and TMT-B performance. Adding the interaction terms increased the variance explained by the models for MoCA (ΔR² = 0.054, p = 0.020) and TMT-B (ΔR² = 0.059, p = 0.010); however, no individual interaction term met the FDR-corrected significance threshold. Conclusions: Among the factors examined, physical activity exhibited the broadest pattern of independent relationships with cognitive performance in older adults with MCI, although the association with verbal fluency was no longer significant after adjustment for multiple testing. Perceived social support was related to a more limited set of cognitive outcomes, while associations involving loneliness were attenuated after FDR adjustment. Because no individual interaction term reached FDR-corrected significance, the interaction results should be regarded as exploratory. The cross-sectional nature of the study precludes conclusions about causality or protective effects. Future longitudinal research incorporating objective assessments of physical activity is warranted to establish the temporal direction and clinical significance of these associations.