Malik VS, Yanping L, Pan A, et al.
Circulation 2019; 139:00-00. DOI:10.1161/CIRCULATIONAHA.118.037401
ATLANTA, GA (March 18, 2019) — While a new observational study suggests an association between long-term consumption of sweetened beverages and the risk of mortality in adults, the study findings were more likely the result of reverse causality.
Researchers utilized data from two cohorts of people to assess the association between both sugar-sweetened and artificially-sweetened beverage (ASB) consumption and the risk of cardiovascular (CVD) and cancer-related mortality. The findings between these two cohorts were very different, therefore they can’t be used to make conclusions about increased risk factors.
For instance, in the Health Professionals Follow-Up Study (HPFS) cohort, no associations were observed between ASB consumption and mortality, including from cardiovascular disease (CVD) or cancer, while in the Nurse’s Health Study (NHS) cohort, associations between ASB consumption and certain health endpoints were reported. However, in the NHS cohort, those risks associated with sugar-sweetened or ASB consumption were reduced once certain dietary and lifestyle factors were controlled for. This is likely the result of residual confounding from risk factors that can contribute to CVD and cancer-related mortality, the likelihood of which is very high with the utilization of observational data, making it inappropriate to point to any one factor. Additionally, the contribution of reverse causality, meaning that individuals already at a greater risk of CVD and/or cancer-related events chose low-calorie sweetened beverages, is very likely the cause of the associations presented by these researchers.
Robert Rankin, president of the Calorie Control Council
“While observational studies can be used to associate behaviors with outcomes, they cannot prove cause and effect. It is likely study subjects were already at a greater risk for these conditions and chose low-calorie sweetened beverages to manage their calorie and sugar intake, as these products are proven safe and beneficial for those managing their weight and blood glucose levels.”
Keri Peterson, MD, medical advisor for the Calorie Control Council, adds, “Low- and no-calorie foods and beverages are a proven tool in helping manage weight. Several studies have shown that changes in behavior and diet, including regular intake of diet sodas, result in successful weight loss and maintenance of that loss.”
The contribution of reverse causality, meaning that low-calorie sweetened beverages were chosen by individuals already at a greater risk of CVD or cancer-related death due to health risks, is likely responsible for the associations being presented by the researchers.
The study results were dependent on self-reported consumption assessed via food frequency questionnaires administered every four years, which is subject to misreporting and was not validated via other assessment measures in this study. Further, baseline data used in this study suggested that those with high intakes of SSBs and ASBs differed in a variety of dietary and lifestyle behaviors, including physical activity, BMI, and red and processed meat consumption and whole grain and vegetable intake. This suggests that there may be other factors that attribute to their risk of CVD and cancer-related mortality.
The observational study has significant limitations and is unable to prove a causal relationship between SSB and ASB consumption and risk of CVD and cancer-related mortality. Observational data can be used to make associations, but is not intended to be used to draw conclusions about any variables and health outcomes. Therefore it is irresponsible to draw conclusions about the consumption of sugar or low-calorie sweetened beverages and potential risks of CVD and cancer-related mortality.