Age, BMI, and inflammation: Associations with emotion recognition.

Area of Science:

• Neuroscience
• Psychology
• Immunology

Background:

• Inflammation is known to impair theory of mind (ToM), the ability to understand others' mental states.
• Previous experimental studies demonstrated this link, but replication in naturalistic conditions was lacking.
• High body weight and advanced age are associated with elevated low-grade inflammation.

Purpose of the Study:

• To conceptually replicate findings that inflammation impairs ToM in states of elevated low-grade inflammation.
• To investigate the association between plasma interleukin-6 (IL-6) levels, body mass index (BMI), age, and emotion recognition.
• To examine how naturalistic conditions of inflammation affect the ability to infer mental states.

Main Methods:

• Ninety participants, divided into young/older age groups and normal/high BMI groups, were recruited.
• Emotion recognition was assessed using the Reading the Mind in the Eyes Test (RMET).
• Plasma IL-6 levels were measured as a biomarker for low-grade inflammation.

Main Results:

• Elevated IL-6 levels were associated with higher BMI but not with increased age.
• Higher IL-6 levels correlated with poorer RMET performance, independent of confounders.
• An interaction showed young, high-BMI individuals performed worse on RMET, while older, high-BMI individuals performed better than their normal-BMI counterparts.

Conclusions:

• The study replicated findings that elevated low-grade inflammation is associated with reduced ability to infer others' mental states.
• Naturalistic conditions of protracted low-grade inflammation may alter emotion recognition and social cognition.
• Findings highlight the impact of inflammation on theory of mind across different age and weight groups.