Supplementary Material for: Examining a healthy lifestyle as a moderator of the relationship between psychological distress and cognitive decline among older adults in the NuAge study

Introduction: The objective of this study was to examine whether a healthy lifestyle composite score of social engagement, physical activity, and Mediterranean diet adherence moderates the association between psychological distress and global cognitive decline among cognitively healthy older adults (67+ years of age at baseline). Methods: A total of 1,272 cognitively intact older adults (Mage = 74.1±4.1 years, 51.9% female) in the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge) completed a series of self-reported questionnaires to measure psychological distress and lifestyle behaviours, and the Modified Mini-Mental Examination (3MS) to assess cognitive performance at baseline and annually over 3 years. Results: Controlling for sociodemographic and health-related characteristics, greater psychological distress associated with steeper cognitive decline over time among males (B = -0.07, 95% CI [-0.12, -0.02]), but not females (B = 0.008, 95% CI [-0.03, 0.04]). Although a healthy lifestyle composite score did not statistically significantly moderate the distress-cognition relationship (B = -0.005, 95% CI [-0.02, 0.01]), there was an association between higher psychological distress and greater cognitive decline at low levels of social engagement (B = -0.05, 95% CI [-0.09, -0.006]), but not at high levels of social engagement (B = 0.02, 95% CI [-0.03, 0.07]). Conclusion: This study suggests that the potentially harmful impact of stress on cognitive function may be malleable through specific healthy lifestyle behaviours and emphasizes the importance of taking a sex-based approach to cognitive aging research.