In the latest edition of her regular #JournalWatch column, Dr Melissa Stoneham reports on a recent study investigating the impact of warning labels for soft drinks.
Melissa Stoneham writes:
Having recently been involved in advocating to the WA State Government to mandate warning labels on alcoholic beverages, it seems only natural to extend our thinking beyond alcohol and into the sugary drink world.
There is clear evidence to state that sugar-sweetened beverage (SSB) consumption contributes to childhood obesity. We also know that several jurisdictions are considering legislative strategies and clinical trials to reduce the consumption of SSBs.
The key question to pose is: should soft drink labels contain warnings about the dangers of sugar, just like cigarettes warn of the dangers of nicotine?
Warnings such as “Children who consume just one sugary drink every day increase their risk for being overweight or obese by 55 percent” might have some effect, but in reality, the evidence for whether warnings such as these would change or influence behaviour is not yet available.
It is important to state upfront that labels on their own are not going to change behaviour. For this to occur, we need a whole suite of additional strategies around the supply and availability of soft drinks, the price of soft drink, the way that it is marketed and the way that many people perceive it as part of their normal day.
In just the same way that cigarette labels have increased awareness about the risks of smoking, soft drink labels would aim to educate and inform people at the point of making a decision.
Generic labelling messages would be less effective than a specific evidence-based statement about how many teaspoons of sugar are in a soft drink and the risks associated with excessive sugar consumption. If this was achieved, the label would act as an information source at the point of decision in the same fashion as warning labels do for cleaning or chemical products.
Modelling impact of policies in the United States
To explore this issue further, this month’s JournalWatch is showcasing a study that looked at the impact of sugar-sweetened beverage point of purchase warning label policies in Baltimore, Philadelphia and San Francisco.
To achieve this, the research team developed models that provided immediate results and a clear understanding of the potential measurable range of benefits resulting from sugary drink labels.
The study, led by Bruce Lee from the Global Obesity Prevention centre at the John Hopkins University, developed a sophisticated modelling program to test the impact of sugary drink labels in a virtual population modelled on the “real-world”.
The methodology is fairly complex, so if you want to read more about this aspect of the study, head to this link.
In short, each virtual individual had data aligned with it that included gender, race and ethnicity, household assignment, school assignment, height and lean and fat tissue masses.
The modelling followed each virtual individual from their home and tracked their movements throughout the virtual city to school and other locations, as they made decisions for meals and snacks.
The virtual people had the opportunity to eat breakfast and lunch at either home or school. One snack could come from home, school, or a retail location; and dinner and two additional snacks could come from either home or a nearby retail location.
The choices were made according to probabilities correlated with each location’s attractiveness and inversely proportional to the location’s geographic distance squared. The retail locations came from a commercially available dataset.
Focus on teenagers
Of specific interest to this study was the tracking of virtual adolescents aged 11 to 18 years. In this research, each virtual adolescent had the opportunity to consume an SSB with each meal or snack. The choice of whether or not to consume an SSB at a particular meal was made according to probabilities determined from surveys of adolescent behaviour.
Teenagers were selected as the target group, as a previous study which accessed 2,202 participants through an online survey, found that teens aged 12 to 18, were a statistically significant 8 to 16 percent less likely to select sugary drinks that had a health warning label compared to sugary beverages with no label.
In addition, the researchers noted that sugary drink warning labels helped teenagers understand the health risks associated with sugary drink consumption.
The warning label used for SSBs in this study is indicative of the one below:
The virtual individuals were simulated 100 times, with each simulation lasting for 365 days for seven years.
The model simulated, over this 7-year period, the mean change in BMI and obesity prevalence.
Although the authors state that SSB warning labels alone are not enough to curb the obesity epidemic, the results are a first step in better understanding ultimate impact of SSB warning labels.
The researchers proposed that implementing sugar-sweetened beverage warning labels at all sugar-sweetened beverage retailers would lower adolescent obesity prevalence in all three cities.
All of these conclusions provide important information for decision makers considering such a policy, some of which have commenced. Examples include the introduction of a Bill that would place warning labels on soda and other sugar-sweetened beverages sold in California and the San Francisco law requiring ads for sugary drinks to display warnings about the products’ possible negative health effects.
One part of the solution
This research provides some evidence that sugary drink labels are one part of the solution.
Public health advocates now need to heed lessons from the tobacco warning labels journey as there is no doubt that the SSB industry’s tactics to resist warning label regulations will heighten.
The industry will continue to challenge the science on health effects of SSBs and any efforts to put warning labels, including challenging the content and design of the labels.
As public health advocates and researchers, we need to be prepared, armed with evidence and ready to lead the charge for policies that support warning labels on sugar sweetened beverages.
• The article – Simulating the Impact of Sugar-Sweetened Beverage Warning Labels in Three Cities. Bruce Lee, Marie Ferguson, Daniel Hertenstein, Atif Adam, Eli Zenkov, Peggy Wang, Michelle Wong, Joel Gittelsohn, Yeeli Mui and Shawn Brown. Published in the American Journal of Preventive Medicine; Volume 54, Issue 2, February 2018, Pages 197-204.
• See previous #JournalWatch columns here.