Dynamic residential movement and depression among the World Trade Center Health Registry enrollees

Purpose: Residential instability is associated with poor mental health, but its causal inference is challenging due to time-varying exposure and confounding, and the role of changing social environments. We tested the association between frequent residential moving and depression risk among adults exposed to the 9/11 disaster. Methods: We used four waves of survey data from the World Trade Center Health Registry. We measured residential movement and depression using geocoded annual address records and the Personal Health Questionnaire Depression Scale, respectively, for a prospective cohort of 38,495 adults. We used the longitudinal Targeted Maximum Likelihood Method to estimate depression risk by frequent residential moving and conducted causal mediation analysis to evaluate a mediating role of social environments. Results: Most enrollees (68%) did not move in 2007–2014, and 6% moved at least once every 4 years. The remaining 26% moved less frequently (e.g., only moving in 2007–2010). Frequent moving versus no moving was associated with risk of depression in 2015–16 (RR = 1.20, 95% CI = 1.06, 1.37). Frequent residential moving—depression pathway was mediated by high social integration (OR = 0.93, 95% CI = 0.90, 0.97). Conclusion: These findings demonstrate the importance of social networks in understanding increased risk of depression associated with housing instability.