Parental characteristics and the risk of schizophrenia in a Chinese population: a case-control study

Background: Genetic studies have provided convergent results indicating that schizophrenia is a polygenic disorder with a heritability estimate of ～60–80%. The propensity for schizophrenia is ～10 times higher in individuals with first-degree relatives with schizophrenia when compared to the general population.

Aim: To identify associations between parental characteristics and the risk of schizophrenia in a Chinese population.

Methods: Participants with a diagnosis of schizophrenia were recruited along with healthy controls (HCs) matched for age and gender from Weifang, China. Logistic regression models and generalized linear models were used to explore the associations between parental characteristics with the risk and age at onset of schizophrenia. In total, 414 cases and 639 HCs were recruited for the study.

Results: We observed an inverse association between levels of paternal and maternal education and risk of schizophrenia after controlling for potential confounders (Paternal: OR?=?1.525, 95% CI: 1.080–2.153, p?=?.017; Maternal: OR?=?1.984, 95% CI: 1.346-2.924, p?=?.001). Younger paternal and maternal childbearing age were associated with a higher risk of diagnosis of schizophrenia. We furtherly observed that individuals with earlier age at onset of schizophrenia had fewer siblings (p?=?.007) and had higher rates of parental marital disharmony (p?=?.033).

Conclusion: Our results indicate that parental years of education and age of childbearing are associated with an increased risk of schizophrenia in a Chinese population. Age of onset of schizophrenia was positively associated with a greater number of siblings and negatively associated with parental marital disharmony.