Evidence mapping: methodologic foundations and application to intervention and observational research on sugar-sweetened beverages and health outcomes1234

Evidence maps are a new method that systematically characterize the range of research activity in broad topic areas and are used to guide research priority setting, systematic reviews, and meta-analyses. We expanded evidence mapping methods by demonstrating their usefulness as a tool for organizing epidemiologic research on sugar-sweetened beverage (SSB) intake and health outcomes: obesity, type 2 diabetes, metabolic syndrome, and coronary heart disease/stroke. We performed a search of the PubMed, Scopus, and Cochrane databases and a hand search of references. Studies selected were reviews and longitudinal studies (intervention and cohort) published between 1 January 1966 and 31 October 2012. We identified and mapped 77 studies (18 review and 59 primary research articles); most of the research focused on obesity (n = 47). For all outcomes, >30% (n = 18) of the primary research studies we identified were not referenced in published reviews. We found considerable variability among primary research studies of SSBs and the 4 health outcomes in terms of designs, definitions of SSBs, and definitions of outcomes, which renders these studies difficult to interpret collectively. For example, we counted 14 different definitions of weight/obesity in 29 observational cohort studies, and ≤6 studies reported the use of the same outcome measure. Establishing field standards in the study of SSB intake and health outcomes would facilitate interpretation across research studies and thereby increase the utility of systematic reviews/meta-analyses and ultimately the efficiency of research efforts. Rapid publication of new data suggests the need for regular updates and caution when reading reviews.