Lack of associations between modifiable risk factors and dementia in the very old: findings from the Cambridge City over-75s cohort study.
To investigate the association between modifiable risk and protective factors and severe cognitive impairment and dementia in the very old. Additionally, the present study tests the predictive validity of the 'LIfestyle for BRAin health' (LIBRA) score, an index developed to assess an individual's dementia prevention potential.



Two hundred seventy-eight individuals aged 85 years or older from the Cambridge City over-75s cohort study were followed-up until death. Included risk and protective factors were: diabetes, heart disease, hypertension, depression, smoking, low-to-moderate alcohol use, high cognitive activity, and physical inactivity. Incident severe cognitive impairment was based on the Mini-Mental State Examination (score: 0-17) and incident dementia was based on either post-mortem consensus clinical diagnostic assessments or death certificate data. Logistic regressions were used to test whether individual risk and protective factors and the LIBRA score were associated with severe cognitive impairment or dementia after 18 years follow-up.



None of the risk and protective factors or the LIBRA score was significantly associated with increased risk of severe cognitive impairment or dementia. Sensitivity analyses using a larger sample, longer follow-up period, and stricter cut-offs for prevalent cognitive impairment showed similar results.



Associations between well-known midlife risk and protective factors and risk for severe cognitive impairment or dementia might not persist into very old age, in line with suggestions that targeting these factors through lifestyle interventions should start earlier in life.
a Alzheimer Centrum Limburg , School for Mental Health and Neuroscience, Maastricht University , Maastricht , The Netherlands.
Kay
K
Deckers
a Alzheimer Centrum Limburg , School for Mental Health and Neuroscience, Maastricht University , Maastricht , The Netherlands.
Sebastian
0000-0002-2398-0609
S
Köhler
a Alzheimer Centrum Limburg , School for Mental Health and Neuroscience, Maastricht University , Maastricht , The Netherlands.
Martin
M
van Boxtel
a Alzheimer Centrum Limburg , School for Mental Health and Neuroscience, Maastricht University , Maastricht , The Netherlands.
Frans
0000-0002-8307-8406
F
Verhey
b Cambridge Institute of Public Health, University of Cambridge , Cambridge , United Kingdom.|c Department of Public Health and Primary Care , University of Cambridge , Cambridge , United Kingdom.
Carol
C
Brayne
b Cambridge Institute of Public Health, University of Cambridge , Cambridge , United Kingdom.|c Department of Public Health and Primary Care , University of Cambridge , Cambridge , United Kingdom.
Jane
0000-0002-8127-2061
J
Fleming
D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000453:epidemiology*; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D065840:Protective Factors; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology
Dementia; cohort study; epidemiology; prevention; risk factors