Jan. 30 (UPI) -- Americans' life expectancy increased in 2018 for the first time in four years, as analyses revealed declines in several of the leading causes of death in the United States, according to figures released Thursday from the Centers for Disease Control and Prevention.
The CDC's "Mortality in the United States: 2018" report says deaths caused by drug overdoses declined for the first time in 28 years, and death rates for six of the 10 leading causes also fell, including cancer.
The nation's age-adjusted death rate for the entire U.S. population decreased by 1.1 percent in 2018, increasing life expectancy to 78.7 years, a slight jump of 0.1 years over 2017.
"The increase in life expectancy from 2017 to 2018, after declines from 2014 to 2017, is largely due to the shift from increasing mortality to a decrease from unintentional injuries, especially drug overdose," Robert Anderson, chief of mortality statistics at the CDC's National Center for Health Statistics, told UPI.
"Life expectancy at birth is often used as an overall measure of population health," he added, which made the three-year decline from a recent high of 78.9 years in 2014 all the more alarming.
According to final 2018 data, there were 723.6 deaths per 100,000 population in the United States that year, down from 731.9 in 2017. The 10 leading causes of death in 2018 remained the same for the third year in a row, with heart disease, cancer and unintentional injuries once again occupying the top three spots.
From 2017 to 2018, death rates increased for just two of the 10 leading causes -- influenza or pneumonia, still eighth on the list, and suicide, which ranked 10th.
"Surely, it is good news that U.S. life expectancy has resumed its advance," Samuel H. Preston, a sociologist at the University of Pennsylvania, told UPI. However, he added, "It was expected based on improvements in medical technology and social progress -- for example, gains in levels of educational attainment."
The NCHS estimated that more than half the increase in life expectancy in 2018 can be attributed to declines in mortality from cancer and accidents or unintentional injuries. Included in the latter number is drug overdoses, which account for more than one-third of all accidental deaths.
From 2017 to 2018, overdose deaths dropped 4 percent from more than 70,000 to 67,367. Nearly 90 percent of all overdose deaths in the United States in 2018 were deemed accidental/unintentional.
The drop in overdose deaths occurred despite increases in the number of deaths linked with synthetic opioids such as fentanyl, fentanyl analogs and tramadol. Deaths related to use of those three drugs increased by 10 percent.
"The recent consecutive decline in life expectancy has been the anomaly and much of that decline seems to have been driven by midlife mortality, in particular drug-related mortality," said Dana A. Glei, a senior research investigator in population health at Georgetown University.
Glei said an analysis she and Preston published this month in PLOS One suggests that "in the absence of drug-related mortality, life expectancy would have continued to increase since 2012."
"In my view, drug use and associated mortality is a major reason why the U.S. has seen the longest continued decline in life expectancy since World War I and the Spanish flu epidemic," Glei said. "The return to a rise in life expectancy suggests that the drug epidemic may have finally peaked. Of course, drug-related mortality is still high among midlife Americans, and we have a long way to go to get back to levels at the turn of the millennium."
Glei noted that the "big reason" for lung cancer deaths declining is the continued drop in smoking within the U.S. population. The NCHS report does not include data on specific cancers, which, Anderson said, is still being analyzed.
In a separate analysis, also released Thursday, the NCHS estimated the national maternal mortality rate to be 17.4 deaths per 100,000 live births, which, the agency said, remains essentially unchanged from 2007, the last time a national figure was reported. The NCHS state is lower than an estimate by NPR and ProPublica in 2017 of 26.4 material deaths per 100,000 live births.