Maternal age and paternal age are associated with distinct childhood behavioural outcomes in a general population birth cohort.
BACKGROUND
Recent studies show that advanced paternal age (APA) is associated with an increased risk of neurodevelopmental disorders such as autism, bipolar disorder and schizophrenia. A body of evidence also suggests that individuals who develop schizophrenia show subtle deviations in a range of behavioural domains during their childhood. The aim of the study was to examine the relationship between paternal and maternal ages and selected behavioural measures in children using a large birth cohort.


METHODS
Participants were singleton children (n=21,753) drawn from the US Collaborative Perinatal Project. The outcome measures were assessed at 7 years. The main analyses examined the relationship between parental age and behavioural measures when adjusted for a range of potentially confounding variables, including age of the other parent, maternal race, socio-economic measures, sex, gestation length, maternal marital status, parental mental illness, and child's age-at-testing.


RESULTS
Advanced paternal age was associated with a significantly increased risk of adverse 'externalizing' behaviours at age seven years. For every five year increase in paternal age, the odds of higher 'externalizing' behaviours was increased by 12% (OR=1.12; 95% CI=1.03, 1.21, p<0.0001). The relationship persisted after adjusting for potential confounding factors. 'Internalizing' behavioural outcome was not associated with advanced paternal age. In contrast, advanced maternal age was significantly protective against adverse 'externalizing' behavioural outcomes, but associated with an increased risk of adverse 'internalizing' behavioural outcomes.


CONCLUSIONS
The offspring of older fathers show a distinctly different pattern of behaviours compared to the offspring of older mothers. The diverse socio-cultural and biologically-mediated factors that underpin these findings remain to be clarified. In light of secular trends related to delayed parenthood, the mechanisms underlying these findings warrant closer scrutiny.
Saha
Sukanta
S
Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Locked Bag 500, Richlands Q4077, Australia.
Barnett
Adrian G
AG
Buka
Stephen L
SL
McGrath
John J
JJ
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D002652:Child Behavior / Q000502:physiology* / Q000523:psychology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010287:Parent-Child Relations; D010331:Paternal Age; D044382:Population Groups; D012307:Risk Factors; D055815:Young Adult