Age differences in the moderating effects of neighbourhood disadvantage on the relationship between physical activity and cognitive function: A longitudinal analysis of the Canadian Longitudinal Study on Aging

Objectives: To explore whether the association between physical activity (PA) and cognition is moderated by neighbourhood disadvantage, and whether this relationship varies with age. Study design: A longitudinal analysis of the Canadian Longitudinal Study on Aging, wherein we included participants (N = 41,599) from urban areas who did not change their residential postal code from baseline (2010-2015) to first follow-up (2015-2018). Main outcome measures: At baseline, we measured PA using the Physical Activity Scale for the Elderly, and neighbourhood disadvantage using the Material and Social Deprivation Indices. Results: Using latent change score regression models, we determined that higher PA at baseline was independently associated with greater maintenance in memory performance from baseline to first follow-up both for adults aged 45-64 (B = 0.04, SE = 0.01, p = 0.001) and for those aged 65+ years (B = 0.12, SE = 0.02, p < 0.001). For participants aged 45-64 years, greater material deprivation was independently associated with declines in memory performance (B = -0.10, SE = 0.03, p < 0.001). In addition, greater social deprivation was associated with a stronger effect of PA on changes in executive functions (B = 0.17, SE = 0.08, p = 0.025) for adults aged 45-64 years; greater material deprivation was associated with a stronger effect of PA on changes in memory performance (B = 0.07, SE = 0.03, p = 0.022). We failed to detect any interactions between PA and neighbourhood disadvantage among adults aged 65+ years (all p values >0.05). Conclusion: For middle-aged adults, the benefits of PA on cognitive performance may be strongest among adults living with greater neighbourhood social and material disadvantages. For older adults, PA may be beneficial to cognitive performance irrespective of neighbourhood disadvantages.