For the first time since 1993, the life expectancy of Americans declined in 2015, dropping from 78.9 years in 2014 to 78.8 years, according to newly released government data. The death rate rose by 1.2 percent.

The single-year decline in life expectancy does not a trend make—it could just be a blip—but the breakdown of the data indicates trouble for middle-aged white people and black men, possibly linked to nationwide trends in obesity and opioid abuse, plus socioeconomic conditions.

That speculation is backed up by research from last year, which found rises in the death rate of middle-aged whites due in part to spikes in suicides, drug overdoses, and alcohol poisoning. At the time, researchers speculated that a blend of health problems, poor healthcare, and despair over unemployment and the financial crisis could be driving up deaths.

The new data analysis, released by the National Center for Health Statistics (NCHS), reveals that between 2014 and 2015, eight of the ten leading killers in the country were slightly more deadly.

Heart disease, which is the top killer, saw a 0.9 percent increase in death rates, killing 168.5 people per 100,000 in 2015. The rate of unintentional injury deaths, such as overdoses and car accidents, increased by 6.7 percent. While the rates of stroke, chronic lower respiratory disease, suicide, diabetes, and kidney disease all jumped between 1.5 and three percent.

The largest increase was in the rate of deaths from Alzheimer’s disease, which jumped 15.7 percent. However, the hike is likely explained by increased reporting, rather than an increase in incidence or deadliness of the disease itself.

The only good news is that the rate of cancer deaths declined by 1.7 percent and the rate of deaths from influenza and pneumonia stayed the same.

The people dying more from those diseases were white men, white women, and black men, which all saw increased death rates between 2014 and 2015. The life expectancy of black women, and Hispanic men and women all stayed the same.

The age groups seeing increases in deaths were young and middle-aged Americans. Infant mortality did not significantly change and the life expectancy of 65-year-olds stayed the same at 19.4 years.

"There are lots of things about this that are unexpected," Robert Anderson, chief of the mortality statistics branch at the NCHS, told NPR. He said that he and his colleagues are keeping a close eye on 2016 statistics to see if there's a trend or if these increases are just a blip. So far, he told NPR that the date from the start of 2016 suggests that it may indeed be a blip. "We'll have to see what happens in the second half of 2016," he said.

Regardless of the small downturn in 2015, America trails many other developed countries in life expectancy, many of which have not reported downturns either. In 2014, the life expectancy for people in Japan was 83.5 and 81 for those in the UK, according to the World Bank.