Researchers investigated whether cold snaps were responsible for increases of overdose deaths.
Periods of cold weather with temperatures at or below freezing can increase opioid overdose death rates by as much as 25%, according to a recently-published study.
The study, published in the journal Epidemiology, looked at information on more than 3,000 overdose deaths in New Jersey and Connecticut between 2014 and 2017. The researchers found that “low average temperature over the 3 to 7 days prior to death were associated with higher odds of fatal opioid overdose.”
Researchers believe there could be a few different explanations for why a cold snap increases the likelihood of overdose.
There may be a biological explanation: opioids can affect breathing, and it is harder to breath in cold air, so this might be compounded. In addition, people who have taken opioids find it harder to regulate their body temperature because opioids reduce the point at which people start shivering, a biological mechanism that helps increase temperature when a person is getting too cold.
In addition, cold temperatures could affect the drug supply chain, making it more likely that people get drugs contaminated with synthetic opioids, researchers speculated. Or, people might be more likely to use drugs alone when it is cold out.
“It is well known that opioids induce respiratory depression, and that’s what causes a fatal overdose,” lead study author Brandon Marshall told Science Daily. “However, there may be a host of other risk factors that contribute to opioid overdose deaths, which could be avenues for effective interventions.”
Marshall emphasized that the reasons don’t matter as much as the fact that lifesaving interventions could be emphasized during cold snaps.
“Regardless of what is causing the correlation between cold weather and fatal overdoses, our findings suggest that agencies and organizations should consider scaling up harm-reduction efforts after a period of cold weather,” he said.
The research showed that the temperature on the day of death wasn’t indicative of increased risk, but that a stretch of cold days was much more likely to affect overdose rates.
“Thirty-two degrees on just one day is cold, but to maintain an average of 32 degrees for three or four days means there was a long time where it was quite cold,” said William Goedel, who helped analyze the data.
However, he noted that is it possible that people are more likely to fatally overdose on cold days, but that is harder to prove with the available data.
“One possibility is that the same-day temperature is based around the recorded day of death, which in some cases is an estimate, especially when a body isn’t found for a couple of days,” Goedel said. “The lack of a strong correlation with temperature on the day of death could be due to the uncertainty of when people actually died.”