Metro/Nonmetro Migration as a Risk Factor for Opioid Use Disorder Among Older Medicare Beneficiaries: A Longitudinal Analysis of 2013–2018 Data

Opioid use disorder (OUD) among older adults (65+) has drawn researchers' attention. Nonetheless, whether migration between a metropolitan (metro) and nonmetropolitan (nonmetro) county shapes the risk of OUD remains underexplored. The drift hypothesis argues that individuals susceptible to a certain health condition tend to move, increasing the prevalence of the health condition in the destinations. By contrast, the environmental breeder hypothesis claims that migration alters the exposures to residential environment factors, which are associated with the occurrence of health conditions. Applying fixed-effects modeling to longitudinal data of older Medicare beneficiaries moving at least once between 2013 and 2018 (<i>N</i> = 6,227, person-year = 28,874), this study finds that older beneficiaries moving between metro and nonmetro counties demonstrated a higher risk of OUD than those who did not move. The positive association between migration and OUD risk is particularly strong for those moving from metro to nonmetro counties and the drift hypothesis receives stronger support.