Reviews examining sugar-sweetened beverages and body weight: correlates of their quality and conclusions

Abstract

Background: The role of sugar-sweetened beverages (SSBs) in increasing obesity is of great scientific, clinical, and public health interest. Many reviews have been published on this topic in recent years with very different conclusions. Objective: We sought to assess the scientific quality and other characteristics that may be associated with the conclusions of reviews regarding the causal relation between SSB consumption and body weight. Design: A systematic search of reviews in English languagepublished peer-reviewed journals in 2006-2013 was performed. Their methodologic quality was assessed by 2 judges using 2 scoring systems: the Assessment of Multiple Systematic Reviews and the American Dietetic Association Quality Criteria Checklist. The conclusions were blindly assessed by 11 independent readers using a Likert scale ranging from a position score of 0 = no evidence of a causal relation to 5 = strong evidence of a causal relation. Results: Twenty reviews were identified: 5 meta-analyses, 3 qualitative systematic reviews, and 12 qualitative nonsystematic reviews. Four received funding from the food industry. Quality scores were neither correlated with the readers' perception of conclusions nor with the source of funding. However, industry-funded reviews were more likely to suggest that evidence supporting a causal relation between SSB consumption and weight gain was weak (mean position score = 1.78), whereas evidence was generally considered well-founded in other reviews (mean position score = 3.39; P # 0.01). Conclusions: For a complex and controversial scientific issue, it is important to minimize perceived or actual threats to scientific objectivity and methodologic quality. More refined tools are needed to better assess their scientific quality and to identify factors and mechanisms that may influence authors' conclusions.

Consumption of sugar-sweetened beverages and its association with overweight among young children from China

“…Similar results were obtained from other studies and reviews (8,9) . Furthermore, Forshee et al in their quantitative meta-analysis and qualitative review, based on the current body of scientific evidence, found the association between SSB consumption and BMI was near zero (10) .…”

Sugar-Sweetened Beverages and Obesity among Children and Adolescents: A Review of Systematic Literature Reviews

“…7,[12][13][14][15][16][17][18]20 Two reviews concluded that there was no association 25,35 and two others, from the same group of authors, reported that no conclusion could be drawn and that more studies were needed. 19,22 No reviews concluded that there was an inverse association.…”

“…11,16,17 Two of these reviews 11,16 studied different health outcomes, and their aims were not toward critically assessing the association between SSB consumption and obesity. Indeed, Weed and colleagues assessed the quality of reviews on SSBs and health outcomes and found that most reviews lacked comprehensive reporting of epidemiological evidence and use of systematic methodologies.…”

“…Their findings showed great study-level methodological variability. 11,16 The third review, 17 examining SSBs and body weight, assessed how reviews' conclusions relate to their quality and source of funding. The results showed that quality scores were not correlated with reviews' conclusions or with the source of funding.…”

On the pitfalls of disclosure statements

“…On the other hand, closer scrutiny and greater scepticism are good things if they are warranted. Systematic reviews have shown that industry-funded studies produce findings more favourable to industry (17)(18)(19) . Past experience with tobacco, fossil fuel, as well as food corporations also suggests that closer scrutiny and scepticism are warranted, since much industry effort has been put into conducting or funding research designed to deflect attention and create doubt or designed for marketing purposes.…”