The relationship between body mass index, sedentary behaviour, and psychosocial outcomes among people with spinal cord injuries


Background: Many people with spinal cord injuries (SCI) reduce or completely stop participating in physical activity post-injury. Furthermore, there is a greater prevalence of negative psychosocial outcomes, such as depression and decreased community integration, post-injury. In the general population, body mass index (BMI) is associated with greater levels of psychological distress and lower well-being, particularly among individuals who are less physically active. Yet little is known about the relationship between sedentary behaviour, BMI and negative psychosocial outcomes among people with SCI. Objective: To determine if BMI moderates the relationship between sedentary behaviour and psychosocial outcomes among community dwelling adults with SCI. Methods: 695 participants (76.2% male, age=46.9 yrs±13.5; years post-injury=15.3 yrs±11.1) completed telephone questionnaires that measured depression, social integration, satisfaction with life, pain, and BMI. Daily activity was measured using the Physical Activity Recall Assessment for People with SCI; sedentary behaviour was measured by subtracting total daily physical activity from total time awake. Moderation was tested using an interaction term in a hierarchical linear regression. Results: Participants were sedentary for 12.8 hours (SD=2.7 hours) per day. Forty-two participants were underweight (6.4%), 280 were normal weight (42.7%), 223 were overweight (34.0%), and 110 were obese (16.1%). The interaction term in the models for depression, satisfaction with life, and pain was not statistically significant (p>.05). In contrast, the interaction term for the social integration model was significant (B=-1.4, p=.02). Analysis of simple slopes revealed that greater sedentary behaviour is associated with lower social integration among overweight and obese participants. Discussion: Sedentary behaviour is particularly problematic for individuals with SCI who are overweight/obese; these individuals may need help becoming active, but also reintegrating socially. Furthermore, understanding why this relationship exists, such as the result of stereotyping and perceived stigma, can assist with the creation of interventions to enhance wellbeing among with population.

Acknowledgments: The lead author is supported by a SSHRC fellowship.