Sociodemographic Characteristics Associated with Pretreatment Weight Change in a Behavioral Weight Loss Intervention

Abstract

Background. Three previous studies found that participants commonly experienced significant weight change before beginning a behavioral weight loss intervention. However, these findings are conflicting in regard to how pretreatment weight change is associated with eventual treatment outcome. Further, these studies measured weight loss outcomes only up to six-months. Thus, the current study aims to examine pretreatment weight change among a diverse sample of active duty military personnel engaged in a behavioral weight loss intervention. Additionally, this study will investigate potential sociodemographic characteristics that influence the relationship between pretreatment change and treatment outcome up to 12-months, as well as how pretreatment weight change is related to intervention adherence. Methods. Using secondary analysis of data from a behavioral weight loss intervention, pretreatment (i.e., screening to baseline visit) weight categories [loss (> 1.15% decrease), stable, or gain (> 1.15% increase)] were compared to % weight change from both screening and baseline visits to four and 12-months. Results. During pretreatment, 59.4% remained weight stable, 24.4% lost and 16.1% gained; and racial differences in group classification were found. In regression models, pretreatment weight categories did not predict baseline to four or 12-month outcomes; however, interactions with age were observed (p = 0.038; p = 0.051, respectively). Weight change category predicted screening to 4-month outcome (p = .0005); specifically, those who lost pretreatment weight were more likely to lose weight from screening to 4-months compared to those who gained or remained weight stable. Pretreatment weight loss was related to consuming more meal replacements by four (p = .025) and 12-months (p = .012) but was not associated with adherence to other intervention protocol. Conclusions. Current results suggest that sociodemographic differences might influence pretreatment weight change and its relationship to 12-month treatment success. Given that many individuals (40.5%) in the current sample experienced significant weight change before the intervention, results extend previous findings suggesting that weight loss trials should account for both screening and baseline visit weights when examining treatment results. Trial Registration: NCT02063178. Registered February 14, 2014. https://clinicaltrials.gov/ct2/show/NCT02063178?term=dissemination+of+look+ahead&rank=1