Passive Sitting Linked to Depression, Not Work Sitting: New Study

A new study published in the Journal of Affective Disorders investigated the associations of mentally passive and mentally active sedentary behaviour with incident depression and the potential mediating roles of C-reactive protein (CRP), waist circumference, and glycated haemoglobin (HbA1c). Participants reported time passively spent TV viewing and watching videos (mentally passive SB) and time sitting while doing light activities such as deskwork or driving a car during worktime (mentally active SB) at 44 and 46 years of age, respectively.

Main findings:

• Mentally passive sedentary behaviour (mainly TV viewing) was associated with a higher risk of developing depression in the long term.

• Mentally active sedentary behaviour (mostly work-related sitting) did not have a significant association with depression.

• Two potential mediators of the connection between mentally passive behaviour and depression were identified:

  • Waist circumference (fat around the middle) explained about 9% of the association.

  • C-reactive protein (inflammation marker) explained about 8% of the association.

  • This suggests that chronic inflammation and weight gain may be involved in the link between mentally passive sitting and depression.

Strengths of the study:

• Investigated both mentally passive and mentally active sedentary behaviours, which is unique and helps to explain different effects on depression.

• A long follow-up period (16 years) allowed for enough cases of depression to be analysed.

• Considered potential biological mediators, offering insights into possible mechanisms.

Limitations:

• Self-reported data: participants reported their own sitting time and depression diagnosis, which could be inaccurate.

• Limited assessment of sedentary behaviours: screen-based sitting (common and possibly related to depression) was not specifically measured.

• Work-related sitting might not be purely "active"; some light activities during work may be mentally passive, explaining the lack of association with depression.

• Changes in behaviour since baseline (2002): sedentary patterns may have shifted with technological advancements.

Implication

• Individuals at risk for depression and with high levels of mentally passive sitting may benefit from interventions to reduce waist circumference and inflammation, such as increased physical activity.

• Public health guidelines should highlight reducing mentally-passive sedentary behavior for mental health benefits.
  

Overall, this study provides important evidence for the differential impact of mentally passive and mentally active sedentary behaviors on depression risk. It also sheds light on potential mechanisms linking these behaviours to depression, suggesting important considerations for future research and public health recommendations.

Depression, affecting approximately 4.4% of the global population, stands as a significant public health concern. Amidst various risk factors, sedentary behavior (SB), defined as any waking behavior while sitting with minimal energy expenditure, has emerged as a noteworthy contributor to the development of depression. Recent research delves into the nuanced relationship between different types of SB and depression, shedding light on the distinction between mentally passive and mentally active sedentary behaviors.

Understanding Sedentary Behavior and Depression

A meta-analysis, incorporating prospective studies, revealed a 10% higher risk of developing depression with increased total sedentary time. However, the type and context of sedentary behavior play a crucial role in this association. Sedentary behavior can be mentally passive (e.g., TV viewing) or mentally-active (e.g., office work), influencing the link with depression differently.

Mentally-Passive vs. Mentally-Active Sedentary Behavior

Recent studies, including the 1958 National Child Development Study conducted in the UK, provide intriguing insights. Mentally passive sedentary behavior, such as TV viewing, was significantly associated with incident depression, with a hazard ratio of 1.43. In contrast, mentally active sedentary behavior, encompassing activities like deskwork, showed no such association.

Potential Biological Mediators

To unravel the underlying mechanisms, researchers explored potential biological mediators. Waist circumference and C-reactive protein were identified as partial mediators for the association between mentally passive sedentary behavior and depression. These findings suggest inflammatory-related mechanisms are contributing to the relationship.

Unraveling the Mediating Role of Waist Circumference

Waist circumference, a marker of adiposity, demonstrated a 9.2% mediation effect. Mentally passive sedentary behaviors often displace time in physical activity, contributing to obesity, a known risk factor for depression. This association could also be linked to the overall health situation of the participant, highlighting the multifaceted nature of the relationship.

Inflammation as a Key Player

C-reactive protein, a marker of inflammation, exhibited an 8.3% mediation effect. Prolonged exposure to mentally-passive sedentary behavior, characterized by long periods of uninterrupted sitting, may trigger low-grade inflammation. This aligns with previous clinical trials linking sedentary behavior to elevated pro-inflammatory markers and mood disturbance.

Glycated Hemoglobin: A Surprising Null Finding

While glycated haemoglobin was associated with incident depression, it surprisingly did not mediate the association with mentally-passive sedentary behavior. This unexpected finding prompts further exploration into the complex interplay between sedentary behaviors, biomarkers, and depression.

Implications and Recommendations

The study's unique strengths, including the assessment of both mentally passive and mentally active sedentary behaviors, contribute valuable insights. The findings emphasize the need for tailored recommendations specific to mental health, focusing on reducing mentally passive sedentary time. Moreover, individuals at risk for depression, exhibiting high levels of mentally passive sedentary behaviors, could benefit from interventions aimed at reducing waist circumference and C-reactive protein through increased physical activity.

Key points

• Mentally passive sedentary behavior is associated with an increased risk of incident depression.

• Mentally active sedentary behavior is not associated with incident depression.

• Waist circumference and CRP partly mediate the association between mentally-passive sedentary behavior and incident depression.

• These findings suggest that inflammatory-related mechanisms may play a role in the association between mentally passive sedentary behavior and depression.

Conclusion

In conclusion, this comprehensive analysis highlights the distinct associations of mentally-passive and mentally-active sedentary behaviors with incident depression. The mediation effects of waist circumference and C-reactive protein underscore the relevance of addressing both metabolic and mental health aspects. As we navigate future research, understanding the intricate interrelationships between sedentary behaviors, inflammation, and adiposity remains pivotal for effective preventive and therapeutic strategies.

Reference Article

Werneck, A. O., Owen, N., Araujo, R. H., Silva, D. R., & Hallgren, M. (2023). Mentally-passive sedentary behavior and incident depression: Mediation by inflammatory markers. Journal of Affective Disorders, 339, 847-853. https://doi.org/10.1016/j.jad.2023.07.053

Related Article

https://healthnewstrend.com/slow-wave-sleep-loss-may-increase-risk-of-dementia

https://healthnewstrend.com/slow-wave-sleep-loss-may-increase-risk-of-dementia

Medical Disclaimer

The information on this website is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.