Car Plant Closures Linked to an Increase in Opioid Overdose Deaths

There exists a link between an increase in opioid overdose deaths and car assembly plant closures, according to the findings a new study published today in the journal JAMA Internal Medicine.

“Fading economic opportunity has been hypothesized to be an important factor associated with the US opioid overdose crisis,” the research authors wrote in their abstract. “Automotive assembly plant closures are culturally significant events that substantially erode local economic opportunities.”

This county-level difference-in-differences study was conducted among adults aged 18 to 65 years in 112 manufacturing counties located in 30 commuting zones with at least one operational car assembly plant. Between January 1999 and December 2016, the researchers assessed age-adjusted, county-level opioid overdose mortality rates before and after automotive assembly plant closures in manufacturing counties affected by plant closures juxtaposed with changes in manufacturing counties unaffected by plant closures.

The study’s primary endpoint was stipulated as the county-level age-adjusted opioid overdose mortality rate. The secondary endpoints were defined as the overall drug overdose mortality rate and prescription versus illicit drug overdose mortality rates. The researchers analyzed the data between April 2018 and July 20, 2019. Overall, during the study period, 29 manufacturing counties in 10 commuting zones were exposed to an automotive assembly plant closure, while 83 manufacturing counties in 20 commuting zones remained unexposed.

According to the results of the study, from 1999 to 2016, car assembly plant closures were linked with statistically significant increases in opioid overdose mortality. Five years after a plant closure, mortality rates had increased by 8.6 opioid overdose deaths per 100 000 individuals (95% CI, 2.6-14.6; P = .006) in exposed counties compared with unexposed counties, an 85% increase relative to the mortality rate of 12 deaths per 100 000 observed in unexposed counties at the same time point. In analyses stratified by age, sex, and race/ethnicity, the largest increases in opioid overdose mortality were observed among non-Hispanic white men aged 18 to 34 years (20.1 deaths per 100 000; 95% CI, 8.8-31.3; P = .001) and aged 35 to 65 years (12.8 deaths per 100 000; 95% CI, 5.7-20.0; P = .001). The researchers noted that they observed similar patterns of prescription versus illicit drug overdose mortality. Moreover, estimates for opioid overdose mortality in nonmanufacturing counties were not statistically significant.

The authors wrote in conclusion that: “These findings highlight the potential importance of eroding economic opportunity as a factor in the US opioid overdose crisis.”