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

•Physical activity (PA) is critical for the maintenance of cognition as adults age.•Socio-economic status (SES) may moderate the relationship between physical activity and cognition•Our results indicate that the benefits of physical activity for cognition are dependent on both age and socio-economic status.•For middle-aged adults, the benefits of physical activity on cognition are strongest for those of low socio-economic status.•For older adults, physical activity is beneficial to cognition irrespective of socio-economic status. To explore whether the association between physical activity (PA) and cognition is moderated by neighbourhood disadvantage, and whether this relationship varies with age. 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). At baseline, we measured PA using the Physical Activity Scale for the Elderly, and neighbourhood disadvantage using the Material and Social Deprivation Indices. 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