Psychometric properties and factor structure of the persian health-promoting lifestyle profile II (HPLP-II) among students at Shiraz University of Medical Sciences: a validation study

Background Promoting healthy lifestyles among students at universities of medical sciences is important for their well-being and may also be relevant to the future professional roles of those training for health-related careers. Although the Health-Promoting Lifestyle Profile II (HPLP-II) is widely used, its psychometric performance has not been examined extensively among students at Iranian universities of medical sciences. This study evaluated the theory-specified six-factor structure of the Persian HPLP-II in this population and used a post-hoc exploratory analysis to investigate possible departures from that structure. Methods A methodological cross-sectional validation study was conducted with 501 students at Shiraz University of Medical Sciences. The theory-specified 52-item correlated six-factor model was tested using confirmatory factor analysis (CFA). Because the items use four ordered response categories, the model was estimated with weighted least squares mean- and variance-adjusted (WLSMV) estimation. A post-hoc exploratory factor analysis (EFA), based on polychoric correlations, parallel analysis, principal axis factoring, and Oblimin rotation, was then used to explore possible structural complexity. Results The primary correlated six-factor CFA produced scaled fit indices of χ²(1259) = 3346.73, CFI = 0.929, TLI = 0.925, RMSEA = 0.058, and SRMR = 0.065. Robust indices were less favorable (CFI = 0.800, TLI = 0.790, RMSEA = 0.083), indicating mixed evidence regarding global fit. Standardized factor loadings ranged from 0.501 to 0.898. Post-hoc parallel analysis suggested an eight-factor empirical solution, whereas the theory-guided six-factor PAF solution retained substantial correspondence with the original domains but also showed several item-level cross-loadings. Residual-covariance models were examined only as sensitivity analyses and were not treated as the final model. Internal consistency was high across the six subscales (Cronbach’s alpha = 0.836–0.917; model-based omega = 0.886–0.947); for the total 52-item scale, alpha was 0.956 and model-based omega was 0.979. Conclusion The findings provide partial, rather than definitive, support for the theory-specified six-domain structure of the Persian HPLP-II among students at Shiraz University of Medical Sciences. The results also indicate sample-specific structural complexity and localized item dependence. Independent cross-validation and further item-level work are therefore needed before stronger conclusions about structural validity or population-specific adaptation are drawn. Clinical trial number Not applicable.