(CNN) - Addictive substances are a huge burden on our collective health.
But in 2015 alone two substances shaved millions of years off our lives.
A new study in the journal, Addiction, discusses the affects of substance abuse.
Substance abuse shaved more than a quarter of a billion years off of our lives collectively in 2015.
Researchers studied data from health organizations around the world.
Their findings provide the most up-to-date information on the effects of substance abuse on our collective health.
Cigarettes and other smoking tobacco products were the biggest burden.
Researchers estimate that 15.2 percent of all adults smoke.
We lost 170.9 million collective life years to smoking tobacco.
Heavy alcohol use produced the second-largest burden despite more people using it.
Of all adults 18.3 regularly use alcohol, according to researcher's estimates.
Heavy drinking cost 85 million collective life years in 2015.
Illicit drug use was the third-largest strain on our health.
Opioids, cocaine, cannabis and amphetamines combined trimmed 27.8 million years off of our lives.
Researchers say more rigorous data collection methods are needed to improve future studies.
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