2016 Trump support was greatest in areas with highest rates of painkiller use

Support for Donald Trump in the 2016 presidential election was greatest in the counties with the highest rates of chronic prescription opioid use, according to a new study published this week in the journal JAMA Network Open.

The study found that Trump received about 39 percent of the 2016 vote in the 638 counties with the lowest rates of long-term (90-day supply or more) Medicare opioid prescriptions, but about 60 percent of the vote in the 693 counties with the highest rates of long-term opioid use. All told, on a scale from zero to 100, where zero indicates no correlation and 100 indicates perfect correlation, the relationship between chronic opioid use and the 2016 presidential vote scored a 42.

Maps illustrating the raw rates of long-term opioid use and the 2016 Trump vote share at the county level illustrate some of the correlation. Certain areas of the country, including parts of the mountain West and a wide swath of Appalachia, stand out on both maps. There are some areas of discordance, however, including much of the northern plains (low opioid rates, high Trump support) and deep South (high opioid rates, low Trump support).

The numbers don’t suggest opioid use was a causal factor in the 2016 presidential vote. Rather, “individual and countylevel socioeconomic measures explained much of the association between the presidential vote and opioid use,” the report found. Those measures included income, disability coverage, insurance and unemployment rates.

Still, correcting for those factors didn’t remove the relationship between the Trump vote and opioid use entirely. “Adjusting for county-level socioeconomic measures in linear regression models explained approximately two-thirds of the association of opioid rates and presidential voting rates,” the authors write. That last third remains something of a mystery.