Psychological Determinants of Purchasing Behavior Among Individuals Indifferent to Reduced-Salt Products.

Background/Objectives: To promote salt reduction before health problems arise, it is important to understand factors associated with reduced-salt product purchasing among consumers with low interest in such products. This study examined psychological determinants of intention to purchase reduced-salt products among Japanese adults who were not actively purchasing them. Methods: An exploratory sequential mixed-methods design was used, including qualitative interviews followed by a cross-sectional web-based survey of 800 men and women aged 18-59 years in Japan. Participants were categorized into precontemplation and contemplation stages based on the transtheoretical model. Associations between purchase intention and three Integrated Behavioral Model categories-attitude, perceived norm, and personal agency-were examined. Percentage-to-gain values were calculated for each belief item. Results: All three category scores were significantly associated with purchase intention, with attitude showing the strongest association (OR = 12.56, 95% CI: 6.93-22.79). In stratified analysis, attitude showed a stronger association in the precontemplation stage (OR = 18.40, 95% CI: 8.51-39.78), whereas no category score was significantly associated with purchase intention in the contemplation stage. In the precontemplation stage, relatively high percentage-to-gain values were observed for holistic wellness-oriented beliefs and product availability in usual supermarkets. Conclusions: Attitude was most strongly associated with intention to purchase reduced-salt products, particularly in the precontemplation stage. Holistic wellness-oriented beliefs and product availability may represent promising targets for future communication or food environment interventions. These findings may provide a basis for future studies testing strategies to increase actual purchases of reduced-salt products and reduce salt intake.