The goal of this study was to test the hypothesis that diabetes self-efficacy mediates the relationship between impulse control and type 1 diabetes (T1D) management from ages 8 to 18 years, using multilevel modeling.
Participants included 117 youth with T1D and their parents. Youth (aged 8-16 years at baseline) and parents were assessed 5 times over 2 years. Using a cohort sequential design, we first estimated the growth trajectory of adherence from age 8 to 18 years, then specified a multilevel mediation model using impulse control as the main predictor, diabetes self-efficacy as the mediator, and changes in adherence (both within- and between-individuals) as the outcome.
According to youth-reported adherence only, self-efficacy partially mediated the within-person effect of impulse control on adherence. On occasions when youth reported increases in impulse control, they tended to report higher adherence, and this was, in part, due to increases in youths’ perceived self-efficacy. Self-efficacy accounted for approximately 21% of the within-person relationship between impulse control and youth-reported adherence. There was no association between impulse control and adherence between-individuals. Impulse control and self-efficacy were not related to parent-reported adherence.
Environments that enrich youth with confidence in their own diabetes-related abilities may benefit self-care behaviors in youth with T1D, but such increases in youths’ perceived competence do not fully account for, or override, the behavioral benefits of impulse control. Efforts to improve adherence in youth with T1D will benefit from consideration of both impulse control and self-efficacy.

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