Development and psychometric evaluation of the Osteoporosis Preventing Behaviors Questionnaire (OPBQ) based on pender’s health promotion model

Osteoporosis affects 38% of women and 25% of men aged ≥ 50 years in Iran, with fracture-related costs estimated at US$393 million annually. Prevention hinges on modifiable behaviors such as adequate calcium intake, weight-bearing exercise, and sun exposure. However, existing instruments like the Osteoporosis Health Belief Scale (OHBS) and Osteoporosis Knowledge Test (OKT) mainly assess beliefs or knowledge and lack cultural adaptation for Middle Eastern populations. Pender’s Health Promotion Model (HPM) offers a comprehensive framework for evaluating preventive behaviors via constructs including perceived benefits/barriers, self-efficacy, planning, substituting behaviors, commitment, and social support. This study aimed to develop and psychometrically test the Osteoporosis Preventing Behaviors Questionnaire (OPBQ) for Iranian women aged 30–60 years, considering socio-cultural factors such as modest clothing that limits vitamin D synthesis. Following COSMIN guidelines, this methodological study was conducted in two phases. In Phase 1, 37 items across six HPM-based subscales were generated from literature, WHO/NOF/IOF recommendations, and expert input. Content validity was assessed by 12 experts (Content Validity Ratio [CVR] ≥ 0.56, Scale-level Content Validity Index [S-CVI/Ave] ≥ 0.90), and face validity by 30 women. In Phase 2, 600 women (mean age 45.2 ± 8.7 years) from Shiraz health centers were recruited via convenience sampling. Construct validity was examined using exploratory factor analysis (principal axis factoring, varimax rotation; KMO = 0.86, Bartlett’s p < 0.001). Reliability was determined by Cronbach’s alpha (≥ 0.70) and test–retest Intraclass Correlation Coefficient (ICC > 0.75) in 30 participants. Content validity was strong (mean CVR = 0.82, S-CVI/Ave = 0.94). EFA supported a six-factor structure explaining 68.4% of variance, resulting in a 35-item OPBQ after removing two low-loading items. Communalities ranged from 0.32 to 0.78, with minimal cross-loadings. Internal consistency was high (α = 0.91 overall; subscales 0.76–0.88) and test–retest reliability robust (ICC = 0.89 overall; subscales 0.78–0.92). The OPBQ is a valid, reliable, and culturally sensitive HPM-based instrument for assessing osteoporosis-preventive behaviors in Iranian women. It can be applied in clinical screenings, educational programs, and public health policy. Broader validation and longitudinal studies are recommended to enhance generalizability.