The association between anxiety and C-reactive protein (CRP) levels: Results from the Northern Finland 1966 Birth Cohort Study

Anxiety frequently accompanies low-grade inflammation-associated conditions like depression, insulin resistance, coronary heart disease and metabolic syndrome. The association between anxiety and low-grade inflammation is, unlike between depression and low-grade inflammation, a very sparsely studied area in general populations. The aim of the present study was to investigate whether anxiety symptoms as well as comorbid anxiety and depressive symptoms are associated with low-grade inflammation at population level.The general population-based Northern Finland 1966 Birth Cohort was followed until age 31 (n=2688 males and 2837 females), when the highly sensitive CRP concentrations were measured. Anxiety and depressive symptoms were defined by Hopkins Symptom Checklist-25 (HSCL-25).After adjusting for confounders, logistic regression analyses showed that anxiety symptoms alone increased the probability for elevated hs-CRP levels (>3.0mg/L) in males over two-fold (2.19 CI 95% 1.08-4.46), while comorbid anxiety and depressive symptoms caused a 1.7-fold (1.76 CI 95% 1.13-2.74) increase in the probability for elevated hs-CRP levels (1.0-3.0mg/L).Our results support the hypothesis that anxiety as well as comorbid anxiety and depression can be associated with an increased risk for low-grade inflammation in males at population level.