Background. The median age at first childbirth has increased dramatically in many high-income countries during the past decades. The psychiatric consequences of this demographic change are insufficiently described on a population level. This study aimed to investigate whether parental age at childbearing is related to psychiatric morbidity among Swedish youths.
Method. This was a cohort study based on Swedish national registers. A national cohort of 292129 children born to primiparas women during 1973–1979 was followed prospectively from 1987 to 2002 in registers. Multivariate Cox analyses of proportional hazards were used to estimate the relative risk of hospital admission for schizophrenia, alcohol and illicit drug abuse, suicide attempts and deaths.
Results. Youths born of teenage mothers had a high risk for suicide death [relative risk (RR) 1·9, 95% confidence interval (CI) 1·3–2·7] and hospital admissions because of suicide attempt (RR 2·0, 95% CI 1·7–2·3) and substance abuse (alcohol: RR 1·6, 95% CI 1·4–1·8; illicit drug: RR 2·2, 95% CI 1·9–2·5) after adjustments for major sociodemographic confounders, compared with children of mothers aged 25–29 years. Offspring of older parents (>34 years) had the highest risk for schizophrenia (RR 1·8, 95% CI 1·0–3·0).
Conclusions. Parental age is related to psychiatric morbidity.