Residential relocation and changes in patterns of environmental exposures by health determinants among children and adolescents in Catalonia, Spain

Residential relocation leads to environmental changes, besides being likely to be influenced by sociodemographic characteristics. The relationship between them is, however, still not well described. We aimed to investigate changes in patterns of urban, natural and physical environmental exposures due to relocation and related sociodemographic determinants in a population-based cohort study of children and adolescents. We included individuals between 0 and 17 years of age, registered in primary healthcare records in Catalonia, Spain from 2006 to 2018 and categorized them as non-movers and movers (first residential change). Hierarchical clustering identified groups of individuals based on their exposure to air pollution, green spaces and built environment. Low, medium and high environmental hazard exposure clusters were identified, which were used to identify changes in environmental exposure patterns due to relocation, namely same, worse, and better environment. Multinomial logistic regression determined whether sex, age, nationality and area-level deprivation influenced these changes. From 1,316,138 individuals, 221,058 were movers. Compared to non-movers, movers were more frequently with foreign nationality (12.1% vs. 21.3%, respectively) and more likely to live in the most deprived areas at baseline (19.2% vs. 24.4%). Younger children had higher risk of moving to better or worse environments. Individuals living in areas with the highest levels of deprivation were least likely to move within the same environments (i.e., either moving to better (Odds Ratio [95% Confidence Interval] 1.39[1.34-1.44]) or worse environment (1.56[1.49-1.63])). Compared to people from Spain, those from Africa moved to similar environments (OR of moving to a better environment 0.90 (0.87-0.94) with respect to move to the same environment, and OR of moving to a worse environment 0.82 (0.78-0.85)), those from America tended to move to other environments (1.17 (1.12-1.23) better and 1.09 (1.03-1.15) worse), while those from Asia and Europe moved to better environments (1.22 (1.12-1.33) and 1.20 (1.14-1.27) respectively). No associations were found for sex. Changes in patterns of environmental exposures due to residential mobility are complex and may be determined by age, deprivation and nationality.