Maternal age and paternal age are associated with distinct childhood behavioural outcomes in a general population birth cohort

Schizophrenia Research
Volume 115, Issues 2-3, December 2009, Pages 130-135
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doi:10.1016/j.schres.2009.09.012 | How to Cite or Link Using DOI
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Maternal age and paternal age are associated with distinct childhood behavioural outcomes in a general population birth cohort




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Sukanta Sahaa, Adrian G. Barnettb, Stephen L. Bukad and John J. McGratha, c, e, ,

a Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Locked Bag 500, Richlands, Q4077, Australia

b Institute of Health and Biomedical Innovation and School of Public Health, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia

c Queensland Brain Institute, The University of Queensland, St Lucia, Q4072, Australia

d Department of Community Health, Brown University, 121 South Main Street, Providence, RI 02903, United States

e Department of Psychiatry, The University of Queensland, St Lucia, Q4072, Australia

Received 23 June 2009; revised 7 September 2009; accepted 7 September 2009. Available online 24 September 2009.

Abstract
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.

Method
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.

Discussion
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.

Keywords: Paternal age; Maternal age; Behaviour; Cohort

Abbreviations: APA, advanced paternal age; CPP, Collaborative Perinatal Project; AMA, advanced maternal age.

Article Outline
1. Introduction
2. Methods
2.1. Assessment of behavioural outcomes
2.2. Statistical analysis
3. Results
4. Discussion
Role of funding source
Contributors
Conflict of interest
Acknowledgements
References
Table 1.
Descriptive statistics of the behavioural factors for paternal and maternal ages (n = 21,753).


a Adjusted for sex of offspring, gestational age, other parent's age, age-at-testing, mother's race, family socio-economic index, marital status, and maternal and paternal psychiatric illnesses.
b Sample size slightly varies between externalizing and internalizing behavioural measures.

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Table 2.
Association between increasing paternal age and maternal age, and behavioural measures in children (n = 21,753).



*p < 0.05, **p < 0.01, and ***p < 0.001.

aAdjusted for sex of offspring, gestational age, other parent's age, age-at-testing, and mother's race.

bAdjusted for sex of offspring, gestational age, other parent's age, age-at-testing, mother's race, family socio-economic index, marital status, and maternal and paternal psychiatric illnesses.


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Corresponding author. Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Locked Bag 500, Richlands, Q4077, Australia.

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Schizophrenia Research
Volume 115, Issues 2-3, December 2009, Pages 130-135