At this point, it’s pretty clear that soda is bad for your health. But a new study has found that it may be even worse than we thought.

Published yesterday in the American Journal of Public Health, the study found that drinking sugar-sweetened beverages may be associated with cell aging. More specifically, researchers studied the effect that soda has on telomeres, which are the protective units of DNA that cap the ends of chromosomes inside human cells. Previously, the length of telomeres within white blood cells has been tied to shorter lifespans as well as the development of chronic diseases such as heart disease, diabetes and certain cancers. In this study, researchers found that telomeres within white blood cells were shorter among people who drank more soda.

“This is the first demonstration that soda is associated with telomere shortness,” said study lead author Elissa Epel, a professor of psychiatry at the University of California-San Francisco, in a news release. “This finding held regardless of age, race, income and education level. Telomere shortening starts long before disease onset. Further, although we only studied adults here, it is possible that soda consumption is associated with telomere shortening in children as well.”

To conduct the study, researchers studied the association between drinking sugar-sweetened beverages, fruit juice and diet soda with telomere length among about 5,300 adults with no history of diabetes or heart disease and who were participating in the National Health and Nutrition Examination Survey. They found that each daily eight-ounce serving of sugar-sweetened sodas was linearly associated with shorter telomeres, which would roughly equal about 1.9 additional years of biological aging. (The average daily sugar-sweetened soda consumption among the study participants was 16.8 ounces.) A daily 20-ounce soda, which is a typical serving size, would translate into about 4.6 additional years of biological aging. Study authors Epel, Cindy Leung, Barbara Laraia, Belinda Needham, David Rehkopf, Nancy Adler, Jue Lin and Elizabeth Blackburn write:

Our hypothesis that consumption of (sugar-sweetened beverages) were related to shorter telomeres was derived from the known effects of (sugar-sweetened beverages) consumption on impaired fasting glucose and insulin resistance. (Sugar-sweetened beverages) have been known to increase oxidative stress and systemic inflammation, which are both processes that can influence telomere attrition. Telomere shortening in response to, and perhaps contributing to, these disease processes was reported, reflecting the overall burden of cardiometabolic disease. Our results suggested that another link between sugar-sweetened soda consumption and metabolic disease might be through shortened telomere length, a biomarker and mechanism of cellular aging.

While sugary sodas did seem to have an effect on telomere length, the study found that drinking 100 percent fruit juice was slightly associated with longer telomeres and no association was observed between telomere length and the consumption of diet sodas or noncarbonated sugar-sweetened beverages. The study noted that soda’s effect on telomere length was comparable to the negative effect of smoking or the positive effect of physical activity on cellular aging.

“Regular consumption of sugar-sweetened sodas might influence disease development, not only by straining the body’s metabolic control of sugars, but also through accelerated cellular aging of tissues,” Epel said.

However, the study authors cautioned that more research is needed, noting that the current study only examined participants at one point in time and that association does not equal causation. Currently, a new study is in the works in which Epel and colleagues will follow a group of study participants over a longer period of time and examine the effects of soda on cellular aging.

To read a full copy of the study, visit the American Journal of Public Health.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.