An SMS intervention to reduce caregiver’s sugar-sweetened beverages: impacts on theoretical constructs and parenting practices from a randomized controlled trial in rural appalachia

Kids SIP<i>smart</i>ER is a school-based behavioural intervention for rural Appalachia middle school students with an integrated two-way short message service (SMS) strategy for caregivers. When tested in a cluster randomized controlled trial, the intervention led to significant improvements in sugar-sweetened beverage (SSB) consumption among students and caregivers. This study explores changes in secondary caregiver outcomes, including changes in caregiver SSB-related theory of planned behaviour constructs (affective attitudes, instrumental attitudes, subjective norms, perceived behavioural control, and intentions), parenting practices, and the home environment. Participants included 220 caregivers (93% female, 88% White, 95% non-Hispanic, mean age 40.6) in Virginia and West Virginia at baseline and 7 months post-intervention. Relative to control caregivers (<i>n</i> = 102), intervention caregivers (<i>n</i> = 118) showed statistically significant improvements in instrumental attitudes (Coef.= 0.53, 95% CI [0.04, 1.01], <i>p</i> = 0.033), behavioural intentions (Coef.=0.46, 95% CI [0.05, 0.88], <i>p</i> = 0.027), parenting practices (Coef. = 0.22, 95% CI [0.11, 0.33], <i>p</i> < 0.001), and total home SSB availability (Coef. = -0.25, 95% CI [-0.39, -0.11], <i>p</i> < 0.001), with specific improvements for sweetened juice drinks (Coef. = -0.18, 95% CI [-0.35, -0.01], <i>p</i> = 0.043) and regular soda/soft drinks (Coef. = -0.31, 95% CI [-0.55, -0.07], <i>p</i> = 0.010). In contrast, there were no significant between group changes for affective attitudes, subjective norms, or perceived behavioural control. Our findings highlight future research areas and fill gaps in intervention literature. This study is among the few to develop and evaluate a scalable, theory-based caregiver SMS component in a rural, school-based intervention. Combined with evidence that Kids SIP<i>smart</i>ER improved SSB behaviours, our results emphasize the potential of theory-guided SMS interventions to impact SSB-related outcomes. <b>Trial registration:</b> Clincialtrials.gov: NCT03740113.