Preterm birth, bullying victimization, and mental health in adulthood: A prospective cohort study in Germany.

Background: To examine the moderating and mediating roles of bullying victimization in the association between preterm birth and mental health in adulthood.

Method: As part of a prospective geographically defined longitudinal study in Germany, 260 adults born very preterm (<32 weeks of gestation) and/or with very low birth weight (birth weight < 1500 g; VP/VLBW) and 229 term-born controls were assessed at the 26-year follow-up. Bullying victimization was reported by parents at 8 and 13 years. At age 26, internalizing symptoms were reported via questionnaire by both participants and parents, and diagnoses for mood and anxiety disorders were obtained via structured interviews. Associations were analyzed using adjusted negative binomial regression and robust Poisson regression models.

Results: We found associations of VP/VLBW birth with internalizing problems in adulthood (adjusted incidence rate ratio (IRR) range: 1.43-2.02). Across both preterm and term-born groups, being bullied, in particular, chronically (more than one time point) was associated with increased internalizing symptoms (adjusted IRR range: 1.27-1.69). Across both groups, bullying victimization at two time points was also associated with increased risk of mood disorders (adjusted IRR 2.08, 95% CI 1.27-3.42). Bullying victimization mediated 15.8% of the effects of VP/VLBW birth on self-reported internalizing symptoms and 8.5% on parent-reported internalizing symptoms. Bullying victimization did not moderate the associations between VP/VLBW birth and mental health outcomes in adulthood.

Conclusions: Our findings suggest that being bullied may have adverse effects on mental health in both VP/VLBW and term-born children that last into adulthood. The association between VP/VLBW birth and internalizing symptoms was partly mediated by bullying victimization in childhood and adolescence.