A population-based study examining soda consumption in 10 European countries found that soft drinks were linked to a greater risk of death, as well as the chance of dying from Parkinson disease.
The study, published in JAMA Internal Medicine, included both sugar- and artificially-sweetened drinks. The study group included 451,743 men and women from Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden, and the United Kingdom, comparing those who drank 2 or more glasses per day with those who drank less than 1 glass per month. There was a higher risk of death from all causes during an average follow-up of 16 years, in which 41,693 deaths occurred.
The authors said the findings support public health efforts to limit soft drink consumption; Tuesday's study follows one published earlier this year in JAMA that found excise taxes on soda sales in Philadelphia reduced overall sales by 38%.
The data came from the ongoing European Prospective Investigation into Cancer and Nutrition (EPIC) trial. Among other factors, participants were excluded if they had reported cancer, heart disease, stroke, or diabetes at baseline, as well as if they had missing soft drink consumption or follow-up information.
On average, participants were nearly 51 years old and mostly female. Higher all-cause mortality was found among participants who consumed 2 or more glasses per day of sugar-sweetened soft drinks (HR, 1.08; 95% CI, 1.01-1.16; P = .004), and artificially sweetened soft drinks (HR, 1.26; 95% CI, 1.16-1.35; P < .001).
The findings revealed a higher risk of death from circulatory diseases from drinking 2 or more glasses of artificially-sweetened drinks per day (but not sugar-sweetened ones). For digestive diseases, mortality was linked to drinking 1 or more glasses per day of sugar-sweetened drinks (but not artificially-sweetened ones).
No association was observed between soft drink consumption and overall cancer death.
Drinking 1 or more glasses of soda per day was positively linked with the risk of dying of Parkinson disease (HR, 1.59; 95% CI, 1.07-2.36; P = .02); however, soft drinks were not associated with Alzheimer disease mortality. The authors said this is the first study to link soft drink consumption to Parkinson disease.
"We have no prevailing hypothesis for the relationship we observed," said Neil Murphy, PhD, corresponding author of the study, in an email to The American Journal of Managed Care® . "It is possible that this result is spurious. Additional epidemiological and experimental studies are now required to investigate this association further."
People who consumed a larger number of soft drinks tended to be younger, be current smokers, and more likely to be physically active. "Other studies in the US have found similarly to us that higher consumers of soft drinks tended to be younger and current smokers. In contrast to these studies, we found that high soft drink consumers were more likely to be physically active," said Murphy.
While soda drinking has been associated with higher rates of obesity, diabetes, and cardiovascular disease in the United States, it has been understudied in European populations and the mortality risk is unknown.
"Two large studies in the US were published earlier this year, but this is the first large-scale European study to examine these relationships. Our analysis was the largest study to date and undertaken in ~450,000 men and women from 10 European countries. We found that higher soft drinks intake was associated with a greater risk of death from all-causes regardless of whether sugar-sweetened or artificially sweetened drinks were consumed," Murphy said. "We are unable to elucidate cause-effect relationships from our study due to its observational design. Our results do, however, provide additional support for the possible adverse health effects of sugar-sweetened soft drinks and to replace them with other healthier beverages, preferably water. For artificially-sweetened soft drinks, we now need a better understanding of the mechanisms that may underlie this association and research such as ours will hopefully stimulate these efforts.
The researchers said in 2010, the worldwide burden of obesity-associated cardiovascular diseases, cancers, and type 2 diabetes associated with consumption of sugar-sweetened soft drinks were estimated to be 184,000 deaths.
Results were unchanged with or without adjusting for the role of body mass index; the authors said that the associations were found even in people with healthy weight, suggesting that perhaps the high glycemic index of sugar-sweetened drinks elevate blood glucose levels, leading to insulin resistance and inflammation.
Limitations of the study include its observational design; in addition, there was only a single assessment of soft drink consumption.
Mullee A, Romaguera D, Pearson-Stuttard J, et al. Association between soft drink consumption and mortality in 10 European countries [published online September 3, 2019]. JAMA Intern Med. doi:10.1001/jamainternmed.2019.2478.