Hui-Xin Wang, Stockholm, Oct Hui-Xin Wang, Ph.D Div. Geriatric Epidemiology Dept. NEUROTEC, Karolinska Institutet & Stockholm Gerontology Research Center

Hui-Xin Wang, Stockholm, Oct Findings from Different studies Biological plausibility

Hui-Xin Wang, Stockholm, Oct Findings from different studies Social network Mental activities Physical activities

Hui-Xin Wang, Stockholm, Oct Social network Social network index Rich Moderate Limited Poor The Kungsholmen Project Fratiglioni et al, Lancet 2000; 355: Relative risks (RR) for dementia

Hui-Xin Wang, Stockholm, Oct PAQUID study Helmer et al, Neurology 1999;53: Marital status RR for dementia Never married 1.9 ( ) EPESE - New Haven cohort Bassuk et al, Ann Intern Med 1999;131:165 Social ties OR for cog decline 0 vs ( ) Social network 2

Hui-Xin Wang, Stockholm, Oct Instrumental support or mental stimulation Social network 3 Possible explanations

Hui-Xin Wang, Stockholm, Oct Mental activities 1 RR for dementia from follow-up studies PAQUID Study Fabrigoule et al, JAGS 1995;43: Travelling 0.5 ( ) Knitting 0.5 ( ) Gardening 0.5 ( ) Manhattan Study Scarmeas et al, Neurol. 2001;57: Leisure activity 0.6 ( )

Hui-Xin Wang, Stockholm, Oct Mental activities 2 RR for dementia from follow-up studies The Kungsholmen Project Wang et al, Am J Epidemiol 2002,155: Mental activities 0.7 ( ) The Religious Order Study Wilson et al, JAMA 2002;287:742-8 Cognitive activity score 0.7 ( ) (1-point increase)

Hui-Xin Wang, Stockholm, Oct Wang et al, Am J Epidemiol 2022;155: Social and leisure activities RR (95% CI) for dementia NO < WeeklyDaily Mental Activity ( ) 0.6 ( ) Social Activity ( ) 0.6 ( ) Productive Activity1 0.8 ( ) 0.6 ( )

Hui-Xin Wang, Stockholm, Oct Canadian Study of Health and Aging Laurin et al, Arch Neurol 2001;58: OR for dementia None1 Low0.64 ( ) Moderate0.69 ( ) High0.63 ( ) Physical activities 1

Hui-Xin Wang, Stockholm, Oct The Kungsholmen Project Wang et al, Am J Epidemiol 2002; 155: OR for dementia None1 Weekly0.97 ( ) Daily0.41 ( ) 3 / 5 cross-sectional studies and 2 / 3 longitudinal studies reported no association Physical activities 2

Hui-Xin Wang, Stockholm, Oct Biological plausibility Experimental studies Studies on other diseases

Hui-Xin Wang, Stockholm, Oct Studies on other diseases 1. Physical activity increases survival and protects against CVD (Bassey 2000) 2. Psychosocial factors (depression and social support) are independent etiological and prognostic factors for CHD (Hemingway and Marmot, BMJ 1999) 3. Social, productive, and cultural activities have a positive influence on survival (Bygren et al, BMJ 1996; Glass et al, BMJ 1999)

Hui-Xin Wang, Stockholm, Oct Physical activity sustains CBF, and improves aerobic capacity (Laurin 2001) 2. Enriched environment improves the plasticity and thickness of old rats’ cerebral cortex (Powell 1994) 3. Poor social network affects the immune system (Seeman 1996) Experimental studies

Hui-Xin Wang, Stockholm, Oct Conclusions Most studies on the topic suport that social and leisure activities may decrease the risk of dementia However Data concerning this topic are limited. More longitudinal studies with better control of confounders and experimental data are necessary.