Moderators of intervention dose effects on diet quality and physical activity changes in a church-based, multicomponent, lifestyle study: Delta Body and Soul III

Authors: Thomson, Jessica; ZOELLNER, JAMIE - Virginia Tech; TUSSING-HUMPHREYS, LISA - University Of Illinois; Goodman, Melissa

Submitted to: Health Education Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2016
Publication Date: 3/4/2016
Citation: Thomson, J.L., Zoellner, J.M., Tussing-Humphreys, L.M., Goodman, M.H. 2016. Moderators of intervention dose effects on diet quality and physical activity changes in a church-based, multicomponent, lifestyle study: Delta Body and Soul III. Health Education Research. 2016;31(3):339-349.DOI:10.1093/her/cyw008.

Interpretive Summary: Advice such as eating a balanced diet and getting sufficient exercise to control and even reverse obesity and its related chronic diseases may be particularly important for minority and other at risk populations who are disproportionately affected by such diseases. However, interventions that are successful in one population may not be effective in a different population. Hence, diet and exercise interventions often need to be tailored or modified to fit the specific strengths, needs, and barriers of populations, like African American communities. The Delta Body and Soul III intervention was designed, implemented, and proven effective for improving diet and increasing physical activity in rural, Southern, primarily African American adults. Despite its success, the existence of subgroups within the intervention group for whom the education sessions were most effective was hypothesized and tested using moderation analysis. Delta Body and Soul III, conducted from 2011 to 2012, was a 6-month, church-based, multicomponent, educational project designed to improve diet quality and increase physical activity in rural, Southern, primarily African American adults in the Lower Mississippi Delta. Despite testing multiple participant characteristics and food shopping and eating behaviors, only three – employment status, food shopping frequency, and individual with primary responsibility for meal preparation – moderated the effects of education session attendance on diet quality changes. There was no evidence for moderation of the effects of exercise class attendance on physical activity changes. In summary, Delta Body and Soul III did prove effective for a range of sociodemogrpahic characteristics and food shopping and eating behaviors in rural, Southern, primarily African American adults. However, in this population at this point in time, this intervention appeared most effective for individuals who had low diet quality, were not employed, lived in households in which others had primary responsibility for meal preparation, and shopped infrequently.

Technical Abstract: Many community-based lifestyle interventions targeting African Americans have reported positive effects on participant’s dietary choices and physical activity habits. However, these effects vary and not all participants will have outcome changes. Moderation analysis can help explain differential effects observed, but are not often reported. Hence, the objective of this secondary analysis was to explore potential moderators of intervention dose effects on diet quality and physical activity outcomes in an effective lifestyle intervention. Delta Body and Soul III, conducted from 2011 to 2012, was a 6-month, church-based, multicomponent, educational intervention designed to improved diet quality and increase physical activity in rural Southern African American adults. Generalized linear mixed models were used to determine associations among indicators of intervention dose received by participants, potential moderators and health outcome changes. Results indicated only three baseline characteristics – employment status, food shopping frequency and individual with primary responsibility for meal preparation – moderated the effects of education session attendance on diet quality changes. No evidence for moderation of exercise class attendance effects on physical activity changes was found. Thus, this culturally targeted, multicomponent lifestyle intervention did induce positive health changes in participants with a range of sociodemographic characteristics and food shopping and eating behaviors.