Personality, health, and brain integrity: the Lothian birth cohort study 1936.
OBJECTIVE
To explore associations between the 5-factor model (FFM; neuroticism, extraversion, openness/intellect, agreeableness, and conscientiousness), personality traits, and measures of whole-brain integrity in a large sample of older people, and to test whether these associations are mediated by health-related behaviors.


METHODS
Participants from the Lothian Birth Cohort 1936 completed the International Personality Item Pool measure, a 5-factor public-domain personality measure (http://ipip.ori.org), and underwent a structural magnetic resonance brain scan at the mean age of 73 years, yielding 3 measures of whole brain integrity: average white matter fractional anisotropy (FA), brain-tissue loss, and white matter hyperintensities (N = 529 to 565). Correlational and mediation analyses were used to test the potential mediating effects of health-related behaviors on the associations between personality and integrity.


RESULTS
Lower conscientiousness was consistently associated with brain-tissue loss (β = -0.11, p < 0.01), lower FA (β = 0.16, p < 0.001) and white matter hyperintensities (β = -0.10, p < 0.05). Smoking, alcohol consumption, diet, physical activity, body mass index and a composite health-behavior variable displayed significant associations with measures of brain integrity (range of r = 0.10 to 0.25). The direct effects of conscientiousness on brain integrity were mediated to some degree by health behaviors, with the proportions of explained direct effects ranging from 0.1% to 13.7%.


CONCLUSIONS
Conscientiousness was associated with all 3 measures of brain integrity, which we tentatively interpret as the effects of personality on brain aging. Small proportions of the direct effects were mediated by individual health behaviors. RESULTS provide initial indications that lifetime stable personality traits may influence brain health in later life through health-promoting behaviors.
Centre for Cognitive Ageing and Cognitive Epidemiology.
Tom
T
Booth
Centre for Cognitive Ageing and Cognitive Epidemiology.
Rene
R
Mõttus
Department of Psychology, University of Edinburgh.
Janie
J
Corley
Centre for Cognitive Ageing and Cognitive Epidemiology.
Alan J
AJ
Gow
Department of Psychology, University of Edinburgh.
Ross D
RD
Henderson
Centre for Cognitive Ageing and Cognitive Epidemiology.
Susana Muñoz
SM
Maniega
Department of Psychology, University of Edinburgh.
Catherine
C
Murray
Centre for Cognitive Ageing and Cognitive Epidemiology.
Natalie A
NA
Royle
Department of Psychiatry, Yale University School of Medicine.
Emma
E
Sprooten
Centre for Cognitive Ageing and Cognitive Epidemiology.
Maria C Valdés
MC
Hernández
Centre for Cognitive Ageing and Cognitive Epidemiology.
Mark E
ME
Bastin
Centre for Cognitive Ageing and Cognitive Epidemiology.
Lars
L
Penke
Centre for Cognitive Ageing and Cognitive Epidemiology.
John M
JM
Starr
Centre for Cognitive Ageing and Cognitive Epidemiology.
Joanna M
JM
Wardlaw
Centre for Cognitive Ageing and Cognitive Epidemiology.
Ian J
IJ
Deary
D000368:Aged; D000375:Aging / Q000523:psychology*; D001008:Anxiety Disorders; D001921:Brain / Q000502:physiology*; D015331:Cohort Studies; D005120:Extraversion, Psychological; D006262:Health; D015438:Health Behavior; D006801:Humans; D007360:Intelligence; D008960:Models, Psychological; D000075384:Neuroticism; D010551:Personality