Applying RE-AIM to Evaluate the External Validity of Weight Gain Prevention Interventions in Young Adults: A Systematic Review

The purpose of this review was to use RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) to assess the extent to which weight gain prevention studies targeting young adults reported on elements of external validity. DESIGN: Systematic review. ELIGIBILITY CRITERIA: Articles of interest included a lifestyle/behavioral intervention targeting weight gain prevention. Eligibility criteria included the following: study design of randomized controlled trials, quasi-randomized control trials, or natural experiments; average participant age between 18 and 35 years; study duration of at least 12 months; and published in English between January 2008 and May 2018. Studies had to report weight or body mass index as a measured outcome and were excluded if they were paired with smoking cessation programs, were conducted in specific groups (ie, pregnant women, breast cancer survivors), or were follow-ups to weight loss studies. STUDY SELECTION: After removing duplicates, the search yielded 11426 articles. Titles and abstracts were screened by 1 reviewer; 144 articles were assessed in a full-text review by 2 reviewers. Discrepancies were resolved by consensus. Nine studies (13 articles) were included in the review. MAIN OUTCOMES MEASURE(S): Reported elements of the RE-AIM framework. RESULTS: A total of 9 studies met the selection criteria. All studies lacked full reporting on external validity elements. Of the total of 60 RE-AIM reporting criteria, 8 were reported by all 9 studies, 26 criteria were reported by fewer than 4 studies, and 22 criteria were not reported by any of the studies. DISCUSSION: There remains inadequate reporting of elements of external validity and generalizability in weight gain prevention studies. This is a significant scientific constraint that limits the information required to disseminate and implement prevention of weight gain interventions for population impact. Standardized reporting may be needed to ensure results that demonstrate not only internal validity but also external validity and generalizability are needed to promote public health impact.