CNN  — 

Life expectancy at birth – the average length of time that you are expected to live – continues to drop for Americans, a new study finds. Drug overdoses, suicides, alcohol-related illnesses and obesity are largely to blame. These problems have been building since the 1980s, according to the study’s authors.

The US had been making steady progress. Life expectancy increased by nearly 10 years over the last half century – from 69.9 years in 1959, to 78.9 years in 2016.

But the pace of this increase slowed over time, while other high income countries continued to show a steady rise in life expectancy.

After 2010, US life expectancy plateaued and in 2014 it began reversing, dropping for three consecutive years – from 78.9 years in 2014, to 78.6 in 2017. This is despite the US spending the most on health care per capita than any other country in the world.

Of all age groups, adults 25 to 64 years old saw the largest increase in mortality rates – 6% – according to the study, published Tuesday in the medical journal JAMA.

The Ohio Valley, which includes West Virginia, Ohio, Indiana and Kentucky, as well as the northern New England area, including New Hampshire, Maine and Vermont, saw the largest relative increases in deaths, the study found.

The researchers looked at data from the US Mortality Database and the US Centers for Disease Control and Prevention’s WONDER database.

Other studies to date have detected this negative trend, but this study went further and noted that problems like drug overdoses and suicides, that are shortening American life expectancy, have been building since the 1990s. Fatal drug overdoses for people in midlife, for example, increased 386.5% between 1999 and 2017, the study found.

For obesity, midlife mortality rates increased 114%. Deaths due to hypertension for this age group increased by 78.9%. Mortality rates linked to alcohol-related problems, such as chronic liver disease and cirrhosis, increased 40.6% overall during that same time period.

For people between the ages of 25 and 34, the rate of alcohol-related disease deaths increased by 157.6% from 1999 to 2017. Suicide rates increased by 38.3% for people ages 25 to 64, and by 55.9% for people ages 55 to 64.

While there are public health initiatives to address these issues, the negative trends in life expectancy are not likely to change any time soon, because the underlying drivers remain. For example, about 80% of adults don’t meet physical activity guidelines, studies show, and the vast majority of American adults are overweight or obese – some 71%, according to the CDC. People who are obese have a higher risk of cancer, diabetes, heart problems and chronic conditions that can cut a life short.

“We can’t always assume an increase in life expectancy year in