Social networks, social participation and cognition: effects across the life-course

Laura Fratiglioni— New York—September 2008

NYC Meeting

Social networks, social participation and cognition: effects across the life-course

MacArthur Foundation Aging Society Network

Laura Fratiglioni


http://www.KI-SU-ARC.se

Bengt Winblad

HuiXin Wang, Stephanie Paillard-Borg

Marti Parker, Anita Karp

Lars Bäckman, Agneta Herlitz, Ross Andel, Stuart MacDonald

USA - Alzheimer’s AssociationSwedish Research Councils FAS and VRSwedish Brain Power Initiative


Social networks, social

participation

and cognition:

Effects across the life-course

The topic

Psychosocial factors

Dementia risk in late life

Personality


OUTLINE

1. Life course approach to dementia risk

2. Current aetiological hypotheses

3. Studied psychosocial factors

4. New studies from the Kungsholmen

Project

NYC Meeting

Psychosocial factors in dementia:

effects across the life-course

MacArthur Foundation Aging Society Network

The Kungsholmen ProjectStockholm, Sweden

1987-89 1994-96 1997-98

1st follow-up

Baseline

1991-93

2nd follow-up

3rd follow-up

1999-2000

4thfollow-up

1810 participants, 75+ old at baselineLiving in a central area of Stockholm

Exposureassessment

Detection of the incident cases


Birth Childhood- Adult life- Old2nd decade Middle age Transition age

Risk Factors

Protective Factors

0 20 60 750

10

20

30

40

50

60

30- 65- 75- 85- 95+

Fratiglioni et al,1999; All continents

Lobo et al, 2000;Europe

Dementia Prevalence per 100



Risk Factors

Protective Factors

0 20 60 75

Genes

Reserve Education, Occupation, Active hypothesis life, Social network

Vascular Midlife hypertension, Diabetes, hypothesis Obesity, Smoking, HD, Stroke

Inflammatory hypoth.: HRT, NSAID

Oxidative stress Diet, Folate & B12, hypothesis Antioxidant

Toxic hypothesis: Occupat. exposures

Psych. stress Drugs, cortisol levels. life events, work-related stress



Risk Factors

Protective Factors

0 20 60 75

Genes

Reserve Education, Occupation, Active hypothesis life, Social network

Vascular Midlife hypertension, Diabetes, hypothesis Obesity, Smoking, HD, Stroke

Inflammatory hypoth.: HRT, NSAID

Oxidative stress Diet, Folate & B12, hypothesis Antioxidant

Toxic hypothesis: Occupat. exposures

Psych. stress Drugs, cortisol levels. life events, work-related stress


Several biological mechanisms contributes to dementia

Psychosocial factors may act through common pathways related to at least 3 hypotheses:

1.Reserve hypothesis

2.Vascular hypothesis

3.Stress hypothesis


Psychosocial factors in dementia

1. Education2. SES

3. Work stress4. Work complexity

5. Social network6. Leisure activity:

mental, physical and social activities

The Faenza Project

De Ronchi et al2005


Biological evidence

Bennett, Wilson et al, Neurology 2003 Religious Order Study, 130 subjects

Global cognitivefunction

Summary meausure of AD pathology

Years of schooling90th percentile

50th percentile

10th percentile

Results from the KP

Adjusted RR for Dementia

Education SES

High High 1

High Low 0.9 (0.2-3.6)

Low High 2.2 (1.3-3.8)

Low Low 2.8 (1.8-4.6)

Karp et al, Am J Epidemiol 2004

SES at age Adjusted20 40 60 RR for AD

High/ High/ High 1

Low/ High/ High 1.5 (0.8-2.9)

Low/ Low/ High 2.4 (1.1-5.4)

Low/ Low/ Low 1.7 (1.0-3.1)

Karp et al, Am J Epidemiol 2004

Father’s occup. (manual/labour):

RR for dementia=4.0 (2.5-6.4)

Moceri et al. 2001

laura fratiglioni, 080125

Risk Factors

Protective Factors

0 20 60 75

Adult life - Middle age

Low Education

Childhood-2nd decade

Low SES



1. Education2. SES




aRR (95%CI)Work complexity

With data 0.9 (0.8-1.0)

With people 0.9 (0.8-1.0)

With things 1.1 (1.0-1.1)

Karp et al, J Am Ger Psychiatry,

in press

Education Work complexity Low Low Ref

High Low Decreased dementia risk

High High Same decrease in dementia risk

Low High Same decrease in dementia risk

Karp et al, J Am Ger Psychiatry,

in press

Risk Factors

Protective Factors

0 20 60 75


Low Education


Low SES

Workcomplexity

Karasek’s job strain model

aRR (95%CI)Work stress

Job controlLow-moderate vs. high 1.9 (1.2-3.0)

Job demands Low-moderate vs. high 1.3 (0.9-1.8)

Wang et al, unpublished data

Wang et al, unpublished data

aRR (95%CI)Job strain

Active Ref

Low strain 0.8 (0.2-3.2)

Passive 1.8 (1.1-3.0)

High strain 1.8 (1.1-2.9)

RR adjusted for age, gender, and education, depressive symptoms and cardiovascular diseases

Risk Factors

Protective Factors

0 20 60 75


Low Education


Low SES

Workcomplexity

Workstress



1. Education2. SES





Social network and dementia incidence

0

5

10

15

20

25

Rel

ativ

e ris

k an

d 95

% C

I

1 2 3 4

1. Extensive social network

2. Moderate social network

3. Limited social network

4. Poor social network

(Fratiglioni et al, Lancet 2000

RR (95%CI)

High mental score 0.71(49-1.03)

High physical score 0.61 (0.42-0.87)

High social score 0.68 (0.47-0.99)

Karp et al, Dement Geriatr Cogn Disord

2005

Risk Factors

Protective Factors

0 20 60 75


Low Education


Low SES

Workcomplexity

Workstress

Poorsocial network

Leisure activity:

-Mental activity-Social activity-Physical activity

SEM- confirmatory analysis

Early Life

Adulthood

Late Life

Education

SES at 20yrs

Psychological demands

Control at work

Complexity with data

Complexity with people

Physical activities

Mental activities

Social activities

e1

e2

e3

e4

e5

e6

e7

e8

e9

Prelim

inar

y

Resul

ts

Adjusted Hazard ratios for dementia

Early LifeAdulthood

Late Life

Continous 0.61 (0.41-0.90)

0.53(0.31-0.91)

0.70(0.53-0.92)

Dichotomised(Median)

0.66 (0.46-0.95)

0.60 (0.42-0.87)

0.52 (0.37-0.73)

Prelim

inar

y

Resul

ts

Separate models


Early LifeAdulthood

Late Life

Continous 0.61 (0.41-0.90)

0.53(0.31-0.91)

0.70(0.53-0.92)

Dichotomised(Median)

0.66 (0.46-0.95)

0.60 (0.42-0.87)

0.52 (0.37-0.73)

Prelim

inar

y

Resul

ts

Same model


Low score in all 3 periods 1

High scores in one or two time periods

0.52(0.30-0.90)

High scores in all three time periods

0.30(0.17-0.52)

Prelim

inar

y

Resul

ts

Social networks, social

participation

and cognition:

Effects across the life-course

The topic

Psychosocial factors

Dementia risk in late life

Personality

Wang et et al, Neurology, in press

Eysenck Personality Inventory

Adjusted HR NeuroticismOne unit decrease 0.98 (0.93-1.03)Low vs. high 0.70 (0.48-1.03) (median)

ExtraversionOne unit decrease 1.07 (0.95-1.09)Low vs. high 1.25 (0.86-1.81) (median)

HRs adjusted for age, sex, education, cognitive functioning, vascular diseases, and depressive symptoms.

Wang et et al, Neurology,in press

Only inactive or socially isolated subjects

Adjusted HR and 95% C

NeuroticismOne unit decrease 0.93 (0.87-0.99)

Low vs. high 0.51 (0.27-0.96) (median)

HRs adjusted for age, sex, education, cognitive functioning, vascular diseases, and depressive symptoms.

Conclusions

1. Psychosocial factors acting at different life periods are equally relevant to decrease dementia risk

2. They may have a cumulative beneficial effect

3. Adulthood and late lifestyle variables seem to emerge as the strongest protective factors

4. Among socially isolated and inactive individuals, even high neuroticism alone may increase dementia risk

SNAC-Kungsholmen

2007 20132010

Ag e g roup 60

Ag e g roup 66

Ag e g roup 72

Ag e g roup 78

Older ag e g roups81+

B

2016

New ag e g roup 81

New ag e g roup 60

2001 2004

B

B

B

B

F 1

F 1

F 1

F 1

F 1

F 2

F 2

F 2

F 3

F 3

B

B

F 2

F 2

F 3

F 4

F 4

F 2F 1

B =bas eline. F 1=firs t, F 2=s econd, F 3=third, F 4=fourth follow-up

C alendarY ears

Thank you for your

attention

AD

VaD

OD

Longitudinal studies on dementia in Europe

MIXED CASES

Aguero-Torres, 2001

The outcome

Distribution of dementia subtypes: incident cases

(Fratiglioni et al, Neurology 2000)

Documents

Social networks, social participation and cognition: effects across the life-course