Adiposity, depression and anxiety: interrelationship and possible mediators

Area of Science:

• Epidemiology
• Psychiatry
• Metabolic Health

Background:

• Adiposity is a growing global health concern.
• Major depressive disorder (MDD) and generalized anxiety disorder (GAD) are prevalent mental health conditions.
• The interplay between obesity, depression, and anxiety requires further investigation.

Purpose of the Study:

• To examine the bidirectional association between adiposity and MDD/GAD.
• To investigate the mediating roles of inflammation, diet quality, and physical activity in this relationship.

Main Methods:

• Analysis of 2,977 individuals from the 1993 Pelotas Cohort (Brazil) at 18 and 22 years.
• Assessment of obesity via BMI, fat mass index, and waist circumference.
• Diagnosis of MDD and GAD using the Mini-International Neuropsychiatric Interview.
• Measurement of C-reactive protein and IL-6 for inflammation, diet quality, and physical activity.
• Logistic regression and G-computation for association and mediation analyses.

Main Results:

• General obesity (BMI, fat mass index, waist circumference) was associated with higher odds of MDD.
• MDD was associated with obesity (BMI), but GAD was not associated with any obesity measure.
• Inflammation (C-reactive protein) partially mediated the effect of MDD on adiposity, but not vice versa.

Conclusions:

• A bidirectional association exists between depression and obesity, with stronger evidence for obesity influencing depression.
• Inflammation is a significant mediator in the depression-to-obesity pathway.
• Further research is needed to elucidate other mechanisms linking obesity and depression.