The study authors emphasized that the work was an observational study that was not able to confirm that the AFib cases in the data set were caused by consumption of sweetened drinks -- but the link remained even after controlling for genetic predisposition to develop the condition.
The team concluded their findings do not prove that the sweetened drinks alter AFiB risk but rather that their consumption may predict AF risk beyond traditional risk factors.
"Our study's findings cannot definitively conclude that one beverage poses more health risk than another due to the complexity of our diets and because some people may drink more than one type of beverage," said lead author Ningjian Wang, a researcher at the Shanghai Ninth People's Hospital and Shanghai Jiao Tong University School of Medicine.
"However, based on these findings, we recommend that people reduce or even avoid artificially sweetened and sugar-sweetened beverages whenever possible. Do not take it for granted that drinking low-sugar and low-calorie artificially sweetened beverages is healthy. It may pose potential health risks."
The study is one of the first to assess a possible link between AFib -- which boosts stroke risk fivefold -- and sweetened beverages, which previous research has linked to Type 2 diabetes and obesity.
According to the AHA's Heart Disease and Stroke Statistics, at least 12 million Americans are predicted to be living with AFib by 2030.
The research team's review of dietary and genetic data from more than 200,000 adults free of AFib at the time they enrolled in Biobank found that among the 9,362 people who went on to develop AFib in the succeeding decade, the risk rose in tandem with sweetened drinks consumption.
Young females with higher body mass index and higher incidence of Type 2 diabetes drank the most artificially sweetened drinks, while young males with a higher BMI, a higher incidence of heart disease and lower socio-economic status drank the most sugar-sweetened drinks.
However, the sugar-sweetened and juice drinkers were more likely to have a higher total sugar intake than the artificially sweetened beverage drinkers.
The study also found smoking may boost sugar-sweetened drinkers' AFib risk, with smokers who drank at least 67 ounces having a 31% higher risk against no statistically significant increase for ex-smokers or those who never smoked.
High consumption of drinks sweetened with sucralose, aspartame, saccharin and acesulfame was associated with a higher AFib risk regardless of genetics.
"Although the mechanisms linking sweetened beverages and atrial fibrillation risk are still unclear, there are several possible explanations, including insulin resistance and the body's response to different sweeteners," Wang said.
Calling the findings "novel," Wang said the association between AFib risk and sugar could lead to the development of new prevention strategies involving reducing the intake of sweetened drinks to improve heart health.
The Biobank data did not contain any information indicating whether the drinks participants consumed contained caffeine -- i.e., if they were so so-called "energy drinks."
Previous AHA guidance recommended avoiding prolonged consumption of low-calorie sweetened beverages by children and that everyone should limit intake of sugar-sweetened drinks. However, it said that artificially sweetened drinks may be a useful replacement strategy to reduce consumption of sugar-sweetened beverages among adults who are regular consumers of large quantities of sugar-sweetened drinks
The co-author of that 2018 guidance, AHA nutrition committee member Penny M. Kris-Etherton, expressed surprise at the study's finding "given that 2 liters of artificially sweetened beverages a week is equivalent to about one 12-ounce diet soda a day."
"This is the first study to report an association between no- and low-calorie sweeteners and also sugar-sweetened beverages and increased risk of atrial fibrillation," she said.
"While there is robust evidence about the adverse effects of sugar-sweetened beverages and cardiovascular disease risk, there is less evidence about adverse health consequences of artificial sweeteners."
Calling for more research to confirm the findings and fully understand all the consequences for heart disease and other health conditions, Kris-Etherton said that until that time water is the best choice and no- and low-calorie sweetened beverages should be limited or avoided.