Relationship between CRP and depression: A genetically sensitive study in Sri Lanka

Area of Science:

• Psychiatry
• Genetics
• Epidemiology

Background:

• Previous research indicates a link between major depression and C-reactive protein (CRP) levels.
• Limited studies have explored shared genetic and environmental factors in this association, particularly outside European populations.
• This study investigates the relationship between CRP levels and depression in a Sri Lankan population.

Purpose of the Study:

• To examine the association between C-reactive protein (CRP) levels and depression symptoms in a Sri Lankan population.
• To investigate the genetic and environmental aetiology of CRP levels and their relationship with depression.
• To assess potential differences in the CRP-depression relationship and CRP aetiology between sexes.

Main Methods:

• Data from 2577 twins and 899 singletons in Colombo, Sri Lanka.
• Depression symptoms assessed using the Beck Depression Inventory (BDI-II).
• High-sensitive CRP blood levels measured via immunoturbidimetry; heritability estimated using Structural Equation Modelling.

Main Results:

• C-reactive protein (CRP) was significantly associated with BMI but not depression (p > 0.05).
• In males, CRP variance was attributed to shared (51%) and non-shared (45%) environmental factors.
• In females, CRP variance was explained by genetic (41%) and non-shared (56%) environmental factors, with a genetic correlation between CRP and BMI observed.

Conclusions:

• The lack of association between depression and CRP supports the hypothesis that inflammation contributes to specific types of depression.
• Environmental factors significantly moderate CRP levels, indicating potential interventions for inflammatory conditions, particularly in males.
• Further longitudinal studies are recommended to accurately assess individual inflammatory states.