Motivational regulation for blood donation among Iranian blood donors: A nationwide mixed-effects study based on...

To investigate the hierarchical structure of blood donation motivation based on self-determination theory (SDT), specifically examining the associations between six regulatory styles-spanning the spectrum from amotivation to intrinsic motivation-and overall donor motivation.

A nationwide cross-sectional study across 31 Iranian provinces enrolled 7187 potential donors (92.4% response rate). Motivation was assessed using the 24-item Self-Regulation of Blood Donation Scale. Multivariable linear mixed-effects models, adjusted for demographic and behavioral confounders, were used for statistical analysis. Bonferroni-corrected pairwise comparisons elucidated the hierarchy, and multiple imputation addressed missing data.

Adjusted mean scores differed significantly across all six regulatory styles (all pairwise p < 0.001). Scores increased progressively across the SDT continuum, from amotivation (adjusted mean = 1.58) to intrinsic motivation (adjusted mean = 4.43). Intrinsic motivation had the highest adjusted score, followed by integrated, identified, introjected, and external regulation. The difference between intrinsic motivation and amotivation was 2.865 points (95% confidence interval [CI]: 2.826-2.904). Adjustment for demographic and donation-related characteristics produced minimal changes in the estimated differences. Sensitivity analyses using multiple imputation yielded comparable results.

Iranian blood donors demonstrated a clear motivational hierarchy consistent with the SDT continuum, with the highest scores observed for intrinsic and other autonomous forms of motivation. These findings support the utility of SDT for characterizing blood donation motivation in Iran and suggest that donor retention strategies may benefit from approaches that support autonomy and the internalization of personally and socially meaningful reasons for donation.