The more added sugar participants consumed, the greater their risk of death from heart disease. Those who consumed 21 percent or more of their daily calories from added sugar were about twice as likely to die from cardiovascular disease during the study compared with those who consumed between 0 and 9 percent of their daily calories from sugar.
The findings held even after the researchers took into account factors that affect heart disease risk, such as body mass index, blood pressure and total calorie intake.
It's important to note the study found only an association, and cannot prove a cause-and-effect relationship between consuming added sugar and dying from heart disease, the researchers said. It's possible that other factors not accounted for in the study, were responsible for the link, they said.
The researchers also assessed consumption of added sugar only at the study start, and it's possible that people changed their consumption over time.
Still, the study findings contribute "to the growing body of research on sugar as an independent risk factor in chronic disease," Laura Schmidt, a professor of health policy at the University of California, San Francisco, wrote in an editorial accompanying the study. "It underscores the likelihood that, at the levels of consumption common among Americans, added sugar is a significant risk factor for [cardiovascular disease death] above and beyond its role as empty calories leading to weight gain and obesity," Schmidt said.