The findings in a study published on diabetes prevalence and sugar availability did not show that sugar causes diabetes. The study showed weak results and had numerous limitations. According to the Calorie Control Council President, Dr. Haley Stevens, “The Basu et al study, which was not able to show cause and effect, contradicts numerous studies that have shown that the amount of fructose typically consumed in the human diet is not associated with an increased risk for diabetes.”
The Calorie Control Council cites the following as serious limitations of this study:
- Supply does not necessarily equal consumption. The authors make the assumption that the availability of sugar is directly related to sugar consumption patterns. It is impossible to ascertain the amount of sugar individuals actually consumed from the amount of sugar that is available.
- Effects were weak and not consistently observed.The fraction of calories that came from sugar was the only significant item correlated with diabetes, and for this item a 1% rise in sugar-based calories was associated with a 0.167% rise in diabetes prevalence. Such a low percentage may not have any clinical significance. Additionally, when the analyses were performed including fruit as a type of sugar, the researchers found no effect on diabetes prevalence rates. Since fruit is a source of fructose, by their assertions, an effect should have been observed.
- The observations are over-extrapolated. It is an ecological fallacy to take data collected about a group and apply it to one individual in the group. The authors combined data from multiple countries to determine if there was an association between sugar availability and diabetes prevalence rates. Consequently, it would be inappropriate to take the results from this study and assume they are applicable to any individual country.
- The study cannot determine cause and effect. Despite the authors’ attempt to address causality with statistical tests, cross-sectional data cannot provide information on causal relationships. The only conclusions that can be drawn from this study are those relating to associations.
- Other factors may have influenced the findings.While the authors did control for factors such as gross domestic product (GDP) per capita, total caloric intake, and the prevalence of overweight and obesity, there is a possibility that other factors influencing the association between sugar availability and diabetes were not included. For instance, genetics is known to play a large role in the development of diabetes and was not accounted for in the analyses. The authors themselves noted in their study, that sugar availability was only able to explain just over 25% of the increase in diabetes prevalence rates seen. That leaves approximately 75% of the disparities in diabetes prevalence rates unexplained.
Diabetes is a complex disease brought on by the convergence of many factors. It cannot be suggested that one factor, such as sugar availability, is responsible for current diabetes prevalence rates.