Story highlights American life expectancy has been cut short by opioids

Current life expectancy for Americans is 78.8 years

(CNN) Opioid drugs -- including both legally prescribed painkillers such as oxycodone and hydrocodone, as well as illegal drugs such as heroin or illicit fentanyl -- are not only killing Americans, they are shortening their overall life spans. Opioids take about 2½ months off our lives, according to a new analysis published in the medical journal JAMA.

In 2015, American life expectancy dropped for the first time since 1993. Public health officials have hypothesized that opioids reduced life expectancy for non-Hispanic white people in the United States from 2000 to 2014. Researchers have now quantified how much opioids are shortening US life spans.

The researchers noted that the number of opioid overdose deaths are probably underestimated because of gaps in how death certificates are completed.

From 2000 to 2015, death rates due to heart disease, diabetes and other key causes declined, adding 2¼ years to US life expectancy. But increases in deaths from Alzheimer's disease, suicide and other causes offset some of those gains. On average, Americans can now expect to live 78.8 years , according to data from 2015, the most recent data available. That's a statistically significant drop of 0.1 year, about a month, from the previous year.

Women can still expect to live longer than men -- 81.2 years vs. 76.3 years -- but both of those estimates were lower in 2015 than they were in 2014.