The study, published in the journal Circulation, suggests poor lifestyle is a major factor that cuts American lives short.
The researchers performed the analysis in the hope of understanding why the USA, which spends more on healthcare as a proportion of GDP than any other nation, ranks 31st in the world for life expectancy at birth.
And yet, numerous most common and costly diseases to treat - such as cancer, cardiovascular diseases, and other chronic conditions - "are largely preventable", they note.
Hoping to extend your life expectancy?
"This study underscores the importance of following healthy lifestyle habits for improving longevity in the USA population", said study author Frank Hu, from Harvard Chan School.
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Although you may think you've heard it all before, the new study emphasizes that even a small change can go a long way and points out just how much this handful of realistic lifestyle goals can impact people's longevity.
They chose to focus on "smoking, excessive alcohol consumption, physical inactivity, poor diet, and obesity", because an analysis of 15 studies covering more than half a million people in 17 nations had concluded that these "unhealthy lifestyle factors" could account for around 60 percent of premature deaths.
The researchers combined data from the Nurses' Health Study and the Health Professionals Follow-up Study - ongoing studies of dietary, lifestyle, and medical data in thousands of US adults - with data from the National Health and Nutrition Examination Survey and mortality info from the Centers for Disease Control and Prevention (CDC). The results showed that following all five lifestyle behaviors is linked to improved longevity for both men and women. For men, it meant an additional 37.6 years, compared to 25.5 years.
Then, from the 2013-2014 results of National Health and Nutrition Examination Surveys, the team estimated the distribution of the five lifestyle factors across the US population and married it to USA death rates from the Centers for Disease Control and Prevention (CDC). For women, it meant an additional 43 years for the healthiest group, compared to 29 years. Researchers also found that study participants who maintained the healthiest lifestyles were 82% less likely to die from cardiovascular disease and 65% less likely to die from cancer when compared with those with the least healthy lifestyles.
Only eight percent of Americans are now following the healthy habits underlined in the study, research co-author Dr. Meir Stampfer, a professor of medicine at Harvard, told CNN.