Venkataramani AS, et al. - Researchers sought to determine the extent to which automotive assembly plant closures were correlated with increasing opioid overdose mortality rates among working-age adults. They performed a county-level difference-in-differences study among adults aged 18 to 65 years in 112 manufacturing counties located in 30 commuting zones (primarily in the US South and Midwest) with at least 1 operational automotive assembly plant as of 1999. In this study, county-level changes were examined between January 1, 1999, and December 31, 2016, in age-adjusted, county-level opioid overdose mortality rates before vs after automotive assembly plant closures in manufacturing counties influenced by plant closures correlated with changes in manufacturing counties unaffected by plant closures. The results showed that automotive assembly plant closures were correlated with increases in opioid overdose mortality between 1999 and 2016. The potential importance of eroding economic opportunity was highlighted as a factor in the US opioid overdose crisis.