An exploratory analysis of the relationship between paternal age at pregnancy and difficulties symptomatic of specific learning disorders among Japanese undergraduate students.

Causes and risk factors of neurodevelopmental disorders originate in the prenatal and perinatal periods. Several studies have demonstrated a relationship between prenatal and perinatal medical records, including maternal and paternal age at pregnancy, and the neurodevelopmental disorders, especially attention deficit/hyperactivity disorder and autism spectrum disorder. However, previous studies showed an association between specific learning disorders and environmental toxins such as lead and tobacco smoke, but not parental age. This study included 993 university freshmen, and their prenatal and perinatal medical data was collected from maternal and child handbooks. A mental health assessment questionnaire consisting of 24 items covering symptoms associated with neurodevelopmental disorders was administered, corresponding to aspects of attention deficit/hyperactivity disorder, autism spectrum disorder, and learning disorders. The relationship between prenatal and perinatal medical data and questionnaire results was statistically analyzed. The number of available records was 881 (88.7%). Using Spearman's rank correlation coefficient analysis and trend analysis, a weak but statistically significant relationship was confirmed between paternal age at pregnancy and the score for learning disorder difficulties. Error accumulation in meiosis during spermatogenesis may be one of the risk factors of learning disorders.