Mediating Role of Physical Activity in the Relationship between Personality Traits and Body Mass Index (BMI) among the Participants of the Employees’ Health Cohort Study of Iran (EHCSIR): A Generalized Structural Equation Modeling

Seyed Abbas  Motevalian; Seyyed Amir Yasin  Ahmadi; Arash  Tehrani-Banihashemi

doi:10.18502/ijph.v54i6.18905

Seyed Abbas Motevalian Research Center for Addiction and Risky Behaviors (ReCARB), Psychosocial Health Research Institute (PHRI), Iran University of Medical Sciences, Tehran, Iran
Seyyed Amir Yasin Ahmadi Preventive Medicine and Public Health Research Center, Psychosocial Health Research Institute, Iran University of Medical Sciences, Tehran, Iran
Arash Tehrani-Banihashemi Preventive Medicine and Public Health Research Center, Psychosocial Health Research Institute, Iran University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/ijph.v54i6.18905

Keywords: Structural equation modeling; Body mass index; Personality; Physical activity; Statistical models

Abstract

Background: Considering the high importance of the problem of obesity and its related factors, we aimed to investigate the mediating role of physical activity in the relationship between personality traits and body mass index (BMI) in the participants of the employees’ health cohort study of Iran (EHCSIR) using generalized structural equation modeling (GSEM).

Methods: A secondary analysis with cross-sectional approach was conducted on the existing data using multilevel GSEM. The primary data of the cohort was collected from July 2017, Iran University of Medical Sciences, Tehran, Iran. Personality traits were exposure, physical activity was the mediator, and BMI was the outcome. Sex was the stratifying variable. Then, pathways with the largest P values were removed one by one using backward stepwise approach.

Results: The data of a total of 3554 participants of EHCSIR were used. Sex was subjected for grouping the analysis. In males, extroversion (EX) was the only personality trait associated with both physical activity and BMI. In the direct pathway, EX was positively associated with BMI. In the indirect pathway, EX was negatively associated with BMI (P <0.1). The total effect was positive. In females, physical activity was not associated with BMI, and therefore, no indirect pathway was formed from personality traits to BMI (P >0.1).

Conclusion: The role of personality traits in obesity was more dominant in females, while in males, physical activity had a role in obesity. The hypothesized mediation pathway of the study title was not approved in females, and in males, was approved only for EX personality trait.