The association between C-reactive protein levels and depression: Results from the northern Finland 1966 birth cohort study.
BACKGROUND
To investigate whether depressive episodes (previous, current single, and recurrent) are associated in both genders with highly sensitive C-reactive protein (hs-CRP) levels, earlier recommended for risk assessment of cardiovascular disease. The impact of the severity of current single and recurrent depressive episodes on this putative association was also investigated.


METHODS
The genetically homogeneous Northern Finland 1966 Birth Cohort was followed until age 31, when, in a cross-sectional setting (n = 5269), the highly sensitive enzyme immunoassay (hs-EIA) method was used to measure CRP concentration. Depressive episodes were defined through mailed questionnaires, including Hopkins Symptom Checklist-25 (HSCL-25) and information on self-reported, doctor-diagnosed depression.


RESULTS
After adjusting for confounders, logistic regression analyses showed that in male subjects, elevated hs-CRP levels (> or =1.0 mg/L) increased the probability for severe current and recurrent depressive episodes 1.7-fold and 3.1-fold, respectively. Correspondingly, an hs-CRP level of >3.0 mg/L increased the probability for recurrent depression up to 4.1-fold. In female subjects, no statistically significant associations were found.


CONCLUSIONS
Our results support the hypothesis that an activation of systemic inflammatory processes may contribute to the pathophysiology of severe depression in men. Further investigations are needed regarding the impact of our findings on diagnostic/treatment strategies concerning severe and, especially recurrent, depression in men.
Liukkonen
Timo
T
Department of Psychiatry, Savonlinna Central Hospital, Savonlinna, Finland. timo.liukkonen@isshp.fi
Silvennoinen-Kassinen
Sylvi
S
Jokelainen
Jari
J
Räsänen
Pirkko
P
Leinonen
Maija
M
Meyer-Rochow
V Benno
VB
Timonen
Markku
M
D000328:Adult; D000428:Alcohol Drinking / Q000378:metabolism; D000437:Alcoholism / Q000150:complications / Q000453:epidemiology; D001794:Blood Pressure / Q000502:physiology; D002097:C-Reactive Protein / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000453:epidemiology* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007249:Inflammation / Q000503:physiopathology; D008019:Life Style; D016015:Logistic Models; D008297:Male; D012008:Recurrence; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000378:metabolism
D002097:C-Reactive Protein; D002784:Cholesterol