Low birthweight and being born to a teenage mother associated with increased risk of suicide in later life

Results of a prospective population study from Sweden in this week’s issue of THE LANCET highlight how low birthweight and being born to a teenage mother are independent risk factors associated with increased risk of suicide in later life.

The study also shows how being born fourth or more in sibling order and poor maternal socio-economic status is associated with an increased risk of suicide attempt.

Previous research to assess the possible association between adverse neonatal, obstetric, and maternal conditions and heightened suicide risk in adolescents has been sparse, yielding conflicting results. No study has hitherto been undertaken to simultaneously analyse specific obstetric and neonatal risk factors and the mother’s psychosocial and socioeconomic conditions, in relation to suicide and attempted suicide in children.

Danuta Wasserman (National Centre for Suicide Research and Prevention/Karolinska Institute, Stockholm, Sweden) and colleagues prospectively followed up over 700,000 young adults born in Sweden between 1973 and 1980. The investigators assessed the proportion of attempted and actual suicide between 10 and 26 years of age.

The overall suicide rate in Sweden in 1999 (when follow-up in the study finished) was around 20 per 100,000 population (see www.ki.se/suicide). Low birthweight (2·kg or less) and children born to teenage mothers were more than twice as likely to commit suicide than the reference population (the majority of individuals in the overall cohort weighing around 3·5kg at birth whose mothers’ age range was 20-29 years at delivery). Significantly raised risk of attempted suicide was reported for individuals of short birth length (hazard ratio 1·29); born fourth or more in birth order (1·79); born to mothers with a low educational level (1·36). The investigators also show how an older maternal age (29 years or more at delivery) was protective against suicidal behaviour of their children.

Dr Wasserman comments: “The reported associations of fetal growth restriction and adverse maternal conditions with suicidal behaviour could be due to parental psychiatric disorders and aggregation of suicide in the family. Maternal mental ill-health might affect fetal growth and socioeconomic position, increase the risk of teenage pregnancies, and exacerbate that of psychiatric disorders in their offspring, which further heightens the risk of suicidal behaviour”.

In an accompanying commentary (p 1102), Maria A Oquendo (Columbia University, New York City, USA, USA) concludes: “… {the} findings supply another step towards the construction of a model for the understanding of suicidal behaviour. Maternal and perinatal factors may be determinants of a diathesis for suicidal behaviour. The identification of effects of intrauterine environment and perinatal environment on suicidal behaviour thus gives us another venue in suicide prevention. Indeed, these data illustrate that good mothering begins well before the day of birth”.