Delayed fathering and risk of mental disorders in adult offspring Saroja Krishnaswamy a , Kavitha Subramaniam b, ⁎, Padma Ramachandran c , Tishya Indran d , Jemain Abdul Aziz e a University of New England, Locked bag 4, NSW 2351, Australia b Department of Physical and Mathematical Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia c Department of Psychology, Middlesex University, London, United Kingdom d Queen Elizabeth Hospital, Adelaide, Australia e Department of Statistics, Faculty of Science and technology, National University of Malaysia, Malaysia abstract article info Article history: Received 9 October 2010 Received in revised form 7 December 2010 Accepted 11 December 2010 Keywords: Common mental disorders Parental age disparity Introduction: Delayed parenting and child bearing at a very young age impose various risks to development of the offspring. Objective: This study aims to investigate the association between disparities in parental age and increased risk factor for common mental disorders in the progenies during adulthood. Methodology: The Malaysian Mental Health Survey (MMHS) was analysed for this study. Respondents were asked to estimate the age of their parents at their birth. Presence of common mental disorders (CMD) was determined by referring to the diagnosis given by the Clinical Interview Schedule-Revised (CIS-R) instrument in the Programmed Questionnaire System (PROQSY) format. The association between parental age disparities and CMD was studied using logistic regression. Result: Fifty three percent (n = 1972) of the MMHS respondents (N = 3666) knew the age of both parents and were included in the study. Three percent (n = 53) had significant disparity in parental age, or a difference of 11 years or more. Respondents born to parents with significant age disparity had a prevalence rate of 24% (95% CI = 22.12–25.89) for CMD in comparison to 6% (95% CI = 5.99–6.11) in their counterparts and 3.4 times higher risk for CMD, after adjusting for demographic factors, paternal age at birth and presence of family history of mental disorders. Amongst those born to older fathers aged 50 and above, the presence of disparity increased the rate for CMD to 42% (95% CI = 39.82–44.18). Discussion: Disparity in parental age was significantly associated with increased risk for CMD. Various psychosocial factors contributing to age disparity in both the father and the mother could predispose to stress and mental health problems. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Older mothers and fathers have been associated with increased rate of deformities in the progeny [1]. This is explained by the increased rate of de novo mutation due to increased cell divisions in the germline of older men [2] accompanied by low activity of DNA repair due to reduced activity of antioxidant enzymes in the seminal plasma and spermatozoa of older men [2,3] and also decreased rate of selection process of spematozoas via apoptosis [4]. Deletion in the mitochondrial gene [5] oxidative stress [1] and pre-ovulatory over- ripeness due to endocrine irregularities [1] in the oocytes of older women also contribute to deformities in the progeny. In mental health, advanced paternal age of 50 and above has been associated with schizophrenia [6–8] and psychosis [9]. Random mutation [9,10] and trinucleotide repeat expansion [10] in the paternal germline, psychological effects of having old parents [11] and early parental loss [8,11] have been used as explanations for the association between delayed fathering and schizophrenia. Increasing maternal age on the other hand has not been established as a cause for these mental disorders. Our earlier work showed that the association between the risk of common mental disorders (CMD) and paternal age at birth formed a J-shaped curve with an odds ratio of 4.28 (prevalence rate of CMD = 25%) for children born to fathers aged 50 and above and 2.90 (prevalence rate of CMD = 10%) for those born to fathers aged 19 and below in comparison to those born to fathers aged between 20 and 29 years [12] (prevalence rate of CMD = 6%). No significant association was observed between maternal age at birth and CMD [12]. The underlying mechanism for such association between paternal age and risk of CMD has not been studied. There is a growing body of Early Human Development 87 (2011) 171–175 ⁎ Corresponding author. Department of Physical and Mathematical Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia. Tel.: +(605) 468 8888x4507. E-mail address: eskei13@yahoo.co.uk (K. Subramaniam). 0378-3782/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.earlhumdev.2010.12.004 Contents lists available at ScienceDirect Early Human Development journal homepage: www.elsevier.com/locate/earlhumdev