Delay Discounting and BMI in Hypertensives: Serial Mediations of Self-Efficacy, Physical Activity and Sedentary Behavior

Objective: Our study aimed to examine the association between delay discounting (DD) and body mass index (BMI) in individuals with hypertension. Additionally, we sought to explore and compare the potential mediating effects of self-efficacy, physical activity and sedentary behavior in this association. Methods: A cross-sectional survey was conducted in two cities in the Jiangsu province of China, specifically Nanjing and Yangzhou, from March to June 2023. A total of 972 hypertensive patients completed the questionnaire (Mage = 64.7 years, SDage = 8.2 years, 54.2% female). Participants engaged in a money choice experiment on computers, provided their height and weight, and completed the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and General Self-Efficacy Scale (GSES). The experimental program was generated using the programming software E-Prime version 2.0. Multiple hierarchical regression analysis was conducted to identify potential covariates. Two serial mediation models were conducted using PROCESS macro 4.1 in SPSS 27.0. Physical activity and sedentary behavior were designated as M2 to investigate and contrast their respective mediating effects in the association between delay discounting and body mass index. Results: Self-efficacy, physical activity, and sedentary behavior served as mediators in the relationship between delay discounting and BMI. Self-efficacy accounted for 14.9% and 14.3% of the total effect in Models 1 and 2, respectively, while physical activity and sedentary behavior each accounted for 14.9% and 9.5% of the total effect, respectively. The serial mediation effects of self-efficacy and physical activity, as well as self-efficacy and sedentary behavior, were significant (B = 0.01, 95% CI [0.01, 0.02]; B = 0.01, 95% CI [0.002, 0.01]), collectively contributing 2.1% and 2.4% of the total effect. Sedentary behavior played a smaller mediating role compared to physical activity in this association. Conclusion: The results indicated that self-efficacy, physical activity and sedentary behavior could act as mediators in the association between delay discounting and BMI, thus potentially mitigating the risk of obesity in hypertensive individuals.