Background Links between childhood residential mobility and pernicious trajectories through to adult maturity are incompletely understood. We therefore carried out a comprehensive investigation of the relationships between residential relocation during upbringing across a broad range of later adverse outcomes.

Methods Using interlinked registers, a national cohort of n=1,475,030 persons born in Demark during 1971–1997 was followed up from 15th birthday to a maximum age of early 40 s for risks of psychiatric morbidity, substance misuse, violent criminality, and natural and unnatural mortality. All cross-municipality residential moves during each age-year between birth and 15th birthday were measured. Survival analyses (© SAS Institute Inc.) was used to estimate incidence rate ratios (IRRs) associated with relocation during each age-year of upbringing. Parental socioeconomic status was delineated according to income, educational attainment and employment status.

Results Elevated risks were observed for virtually all outcomes examined, with excess risk seen among those who experienced multiple versus single relocations in a year. For attempted suicide, violent offending, substance misuse, personality disorders and unnatural deaths, we observed especially sharp spikes in risk linked with multiple relocations in a year during early/mid-adolescence. For example, diagnosis for substance misuse from age 15 was over six times more likely among adolescents who moved two or more times at age 14 than for their peers (IRR 6.35; 95% CI 5.82, 6.92). With violent offending and attempted suicide, our two primary outcomes, we found a risk gradient with increasing age at exposure among higher as well as lower socioeconomic groups. A consistent pattern of markedly elevated risk was not seen among all psychiatric illnesses examined; thus, eating disorders and obsessive compulsive disorder were not strongly linked with residential mobility during upbringing.

Conclusion As with other register-based studies, potential for residential confounding is a limitation of this investigation. Nonetheless, whatever causal mechanisms are implicated, frequent residential change is a strong marker for serious familial adversities. Heightened vigilance is therefore indicated for relocated youths. Health, educational and social services should be mindful of the potential psychosocial needs of adolescents who have recently moved homes or who have relocated more than once over a short period, and effective risk management will require close cooperation between multiple public agencies. When addressing the vulnerabilities of troubled young people, the possible harmful impact of residential relocation during childhood should be considered for individuals from affluent or middle class backgrounds, as well as those who grew up in deprived families.