Development and validation of a questionnaire for diabetes prevention behaviors based on the behavior change wheel framework in Iranian adults with prediabetes

The rising prevalence of prediabetes necessitates theory-based instruments to assess behavioral determinants and guide prevention. This study developed and validated a questionnaire based on the Behavior Change Wheel (BCW) for Iranian adults with prediabetes. This cross-sectional psychometric study included 500 adults with prediabetes from eight health centers in Karaj, Iran (August 2024–March 2025), selected via proportionate stratified cluster sampling. An initial 160-item pool was generated from qualitative interviews, literature, and existing tools. Content and face validity, exploratory and confirmatory factor analyses (EFA/CFA), structural equation modeling (SEM), and reliability were assessed. The questionnaire showed excellent content validity (mean CVR = 0.91, S-CVI/Ave = 0.95, impact score = 3.07). EFA yielded a stable seven-factor structure explaining 47.64% of the variance. CFA confirmed this structure with excellent fit (χ 2 /df = 1.57, CFI = 0.964, TLI = 0.961, RMSEA = 0.044, RMR = 0.048). Convergent and discriminant validity were established (CR = 0.881–0.974; AVE = 0.643–0.824; √AVE = 0.802–0.908). In SEM, psychological capability was positively associated with reflective (β = 0.69) and automatic motivation (β = 0.42), Physical capability was positively associated with reflective (β = 0.20) and automatic motivation (β = 0.15), Physical Opportunity (β = 0.34) and Social Opportunity (β = 0.31) exerted strong, significant positive effects on Automatic Motivation, While their influences on Reflective Motivation were negligible and statistically non-significant (Physical Opportunity: β = 0.06, p = 0.197; Social Opportunity: β = 0.04, p = 0.357). The model explained 48%, 39%, and 52% of the variance in reflective motivation, automatic motivation, and preventive behavior, respectively. The final 56-item version showed excellent internal consistency (α = 0.931) and test–retest reliability (ICC = 0.93). The BCW-based questionnaire is a valid, reliable, and culturally appropriate instrument for assessing diabetes prevention determinants in Iranian adults with prediabetes. It may facilitate behavioral assessment, theory-driven intervention design, and public health strategies to reduce the diabetes burden in Iran and similar Middle Eastern contexts.