On average, life expectancy across the globe is steadily ticking upward—but the same can’t be said for the United States. Three reports newly published by the Centers for Disease Control and Prevention highlight a worrying downward trend in Americans’ average life expectancy, with the country’s ongoing drug crisis and climbing suicide rates contributing to a third straight year of decline.

As Lenny Bernstein notes for The Washington Post, the three-year drop represents the longest sustained decline in expected lifespan since the tumultuous period of 1915 to 1918. Then, the decrease could be at least partially attributed to World War I and the devastating 1918 influenza pandemic. Now, the drivers are drug overdoses, which claimed 70,237 lives in 2017, and suicides, which numbered more than 47,000 over the same period. Both of these figures rose between 2016 and 2017.

“Life expectancy gives us a snapshot of the Nation’s overall health,” CDC Director Robert R. Redfield said in a statement, “and these sobering statistics are a wakeup call that we are losing too many Americans, too early and too often, to conditions that are preventable.”

According to Ars Technica’s Beth Mole, 2015 marked the first recorded drop in U.S. life expectancy since 1993, with Americans shaving an average of 0.1 years off of their lifespans. The same proved true in 2016 and 2017, Cathleen O’Grady writes in a separate Ars Technica piece, making the latest projection 78.6 years, down 0.3 years from 2015’s 78.8. Broken down by gender, men could expect to live an average of 76.1 years, down from 76.2 in 2016, while women could anticipate living until 81.1, the same age projected in 2016.

Although the country’s aging Baby Boomer population factored into the decline, Mike Stobbe of the Associated Press reports that increased deaths amongst younger and middle-aged individuals (particularly those between 24 and 44) had an outsized effect on calculations.

As Kathryn McHugh of Harvard Medical School tells NPR’s Richard Harris, “We're seeing the drop in life expectancy not because we're hitting a cap [for lifespans of] people in their 80s, [but] because people are dying in their 20s [and] 30s.”

The overall number of deaths across the U.S. totaled 2.8 million, or 69,255 more than in 2016, Erin Durkin notes for The Guardian. Of the top 10 leading causes of death—heart disease, cancer, unintentional injuries (drug overdoses constituted slightly less than half of this category in 2017), chronic lower respiratory disease, stroke, Alzheimer’s, diabetes, influenza and pneumonia, kidney disease, and suicide—only cancer witnessed a decrease in mortality rates. Seven, including suicide and unintentional injuries, experienced increases.

Josh Katz and Margot Sanger-Katz of The New York Times note that the rising number of overdose deaths corresponds with the growing use of synthetic opioids known as fentanyls. Deaths involving fentanyl increased more than 45 percent in 2017 alone, while deaths from legal painkillers remained stable from 2016 to 2017. To date, the overdose epidemic has wrought the most devastation in Northeast, Midwest and mid-Atlantic states.

Robert Anderson, chief of the Center for Health Statistics’ mortality branch, tells the Post’s Bernstein that the leveling off of prescription drug deaths may be the result of public health initiatives designed to curb the widespread availability and subsequent abuse of such medicines. Still, the rising prevalence of fentanyl, which is often mixed with heroin or falsely marketed as heroin, means the nation’s drug crisis is far from over.

In terms of deaths from suicide, Bernstein writes that there is a huge disparity between urban and rural Americans. The suicide rate amongst urban residents is 11.1 per 100,000 people, as opposed to rural residents’ 20 per 100,000.

“Higher suicide rates in rural areas are due to nearly 60 percent of rural homes having a gun versus less than half of homes in urban areas,” psychiatrist and behavioral scientist Keith Humphreys of Stanford University says. “Having easily available lethal means is a big risk factor for suicide.”

Speaking with NPR, disease prevention expert William Dietz of George Washington University stressed the links between overdoses and suicides. Both may occur amongst people “less connected to each other in communities” and are tied to a “sense of hopelessness, which in turn could lead to an increase in rates of suicide and certainly addictive behaviors.”

McHugh echoes Dietz, concluding, “There's a tremendous amount of overlap between the two that isn't talked about nearly enough.”