Who is (Not) Engaging in a Father-Inclusive Digital Parenting Intervention in Tanzania: An Analysis of Predictors (Preprint)

BACKGROUND Digital interventions offer a promising avenue for scalable parenting support in low- and middle-income countries (LMICs), where in-person coverage remains limited. However, engagement disparities may reduce their potential for population-level impact. OBJECTIVE This study examined caregiver-level predictors of engagement with ParentApp, a father-inclusive, smartphone-based adaptation of the Parenting for Lifelong Health Teens program for caregivers of adolescents aged 10–17 years. METHODS This study was nested within a cluster-randomized factorial trial of ParentApp in Mwanza, Tanzania, implemented according to the optimization phase of the Multiphase Optimization Strategy (MOST). Sixteen clusters (N=614 caregivers, 33.4% male) were randomized to three components: guidance (guided vs. self-guided), app design (unstructured vs. structured), and digital support (enhanced vs. basic). Digitally tracked app engagement outcomes comprised number of modules completed, time to first non-start, and time to first non-completion. Baseline candidate predictors included demographic, socioeconomic, behavioral, and psychological factors assessed via an app-embedded questionnaire. Poisson generalized linear mixed-effects models with random effects for cluster assessed associations between predictors and each outcome. Interaction terms were specified to test whether associations differed by caregiver gender. RESULTS Among 614 participants, 596/614 (97.1%) completed module 1; this declined to 281/614 (45.8%) for module 2, with 49/614 (8.0%) completing all 12 modules. Mean content completion across the program was 35.6% (SD 33.1%). Women completed approximately 15% more modules compared to men (incidence rate ratio [IRR] 1.15, 95% CI [1.05, 1.27], P=.003), despite reporting higher financial stress, food insecurity, child maltreatment, and depressive symptoms at baseline (all P≤.023; Cohen’s d=0.19–0.37). No other main effects or gender interactions were statistically significant. CONCLUSIONS This is the first known study to investigate caregiver-level predictors of engagement with a digital parenting intervention in an LMIC. Engagement with ParentApp was broadly consistent across caregiver subgroups, with the exception that women completed significantly more modules than men. To equitably engage men and fathers, future studies should pair father-inclusive, identify-affirming content with implementation strategies that reduce social and economic barriers to participation. CLINICALTRIAL Pan-African Clinical Trial Registry PACTR202210657553944; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=24051 INTERNATIONAL REGISTERED REPORT RR2-10.1186/s12889-023-15989-x