The death rate in the U.S. rose in 2015 for the first time in a decade. Preliminary data show the spike was partially driven by an increasing number of people dying from drug overdoses, suicide and Alzheimer's disease, according to The New York Times.
Another killer, heart disease, crept up slightly after years of decline.
The death rate, which is measured as the number of deaths per 100,000 people, has been declining in the U.S. for years as a result of improvements in health, disease management and medical technology, according to the report.
Here are seven things to know about last year's rise in the death rate, according to The New York Times.
1. In 2015, the death rate rose to 729.5 deaths per 100,000 people, up from 723.2 in 2014, according to the National Center for Health Statistics. Last year marked one of the few times the rate increased over the last 25 years, according to the report. In 2005 a particularly bad flu season bumped it up, and AIDS and the flu contributed to a spike in 1993.
2. In taking a closer look at recent research, a sharp rise in death rates is most apparent in certain groups, such as less educated whites, who have been the most impacted by the prescription drug abuse epidemic. Increases for the entire population are rare, according to the report. However, preliminary data is not broken down by race, so it is too early to tell whether increasing national mortality can be fairly attributed to one subset of the population.
3. The increase in mortality in 2015 was surprising to health experts. "We are not accustomed to seeing death rates increase on a national scale," said Andrew Fenelon, PhD, a researcher at the CDC, according to the report. "We've seen increases in mortality for some groups, but it is quite rare to see it for the whole population."
4. One factor that may have contributed to the uptick in the death rate is that mortality from heart disease, which had been declining for decades, has flattened. That means other causes of death have more influence, as they are no longer offset by the steep decline of heart disease-related deaths.
5. The mortality rate from heart disease in 2015 was 167.1, up from 166.7 in 2014, . Although last year marks the first since 1993 that the rate did not decline, experts do not call the increase statistically significant.
6. The death rate for drug overdoses rose to 15.2 per 100,000 deaths in the second quarter of 2015, compared with 14.1 in the same period during the prior year. The rate for unintentional injuries, which include drug overdoses and car accidents, rose to 42 in the third quarter of 2015, up from 39.9 during the same period of 2014, according to the report.
7. The mortality rate for Alzheimer's disease was also up in 2015, increasing to 29.2 from 25.4 in 2014, according to the report. The rise is a continuation of several years of increases.