Offspring born to couples married for <3 years, across all paternal ages, harbored a small increased risk for schizophrenia, which was independent of parental psychiatric disorders and paternal age, according to a recent study. Furthermore, fathers who married late had particularly short duration of marriage (DoM), which, along with paternal age, completely explained the risks related to later paternal age at marriage. Relative risks (RR) for schizophrenia were estimated using continuous and stratified Cox proportional hazards models in the 90,079 offspring from a prospective population-based birth cohort study (1964–1976). Schizophrenia diagnosed in offspring and parental diagnoses of schizophrenia or other psychiatric conditions were identified by cross-linkage to a psychiatric case registry. Researchers found:
- In the full model, RR for schizophrenia decreased for each 5 years DoM: 0.83 (0.75–0.95).
- Stratified analyses showed the greatest RR risk for DoM <2 years: 1.53 (1.11–1.66) with lesser risk for 2–4 years DoM: 1.38 (1.05–1.81) compared to more DoM of ≥10 years.
- The apparent risk related to later fathers' age at marriage (1.27) was eliminated in after accounting for DoM and later paternal age.
Malaspina D, Kranz T, Kleinhaus K, et al. Short duration of marriage at conception as an independent risk factor for schizophrenia. [Published online ahead of print March 8, 2019]. Schizophr Res. doi:10.1016/j.schres.2019.03.001.