Elsevier

Brain, Behavior, and Immunity

Volume 59, January 2017, Pages 253-259
Brain, Behavior, and Immunity

Full-length Article
Serum C-reactive protein in adolescence and risk of schizophrenia in adulthood: A prospective birth cohort study

https://doi.org/10.1016/j.bbi.2016.09.008Get rights and content
Under a Creative Commons license
open access

Highlights

  • This is one of the first longitudinal studies of serum CRP & subsequent schizophrenia.

  • Elevated serum CRP in adolescence is associated with risk of adult schizophrenia.

  • The CRP-schizophrenia association is consistent with a dose-response relationship.

Abstract

Objective

Meta-analyses of cross-sectional studies confirm an increase in circulating inflammatory markers during acute psychosis. Longitudinal studies are scarce but are needed to understand whether elevated inflammatory markers are a cause or consequence of illness. We report a longitudinal study of serum C-reactive protein (CRP) in adolescence and subsequent risk of schizophrenia and related psychoses in adulthood in the Northern Finland Birth Cohort 1986.

Method

Serum high-sensitivity CRP was measured at age 15/16 years in 6362 participants. ICD-10 diagnoses of schizophrenia and related psychoses were obtained from centralised hospital inpatient and outpatient registers up to age 27 years. Logistic regression calculated odds ratios (ORs) for psychotic outcomes associated with baseline CRP levels analysed as both continuous and categorical variables using American Heart Association criteria. Age, sex, body mass index, maternal education, smoking, and alcohol use were included as potential confounders.

Results

By age 27 years, 88 cases of non-affective psychosis (1.38%), of which 22 were schizophrenia (0.35%), were identified. Adolescent CRP was associated with subsequent schizophrenia. The adjusted OR for schizophrenia by age 27 years for each standard deviation (SD) increase in CRP levels at age 15/16 years was 1.25 (95% CI, 1.07–1.46), which was consistent with a linear, dose-response relationship (P-value for quadratic term 0.23). Using CRP as a categorical variable, those with high (>3 mg/L) compared with low (<1 mg/L) CRP levels at baseline were more likely to develop schizophrenia; adjusted OR 4.25 (95% CI, 1.30–13.93). There was some indication that higher CRP was associated with earlier onset of schizophrenia (rs = −0.40; P = 0.07).

Conclusions

A longitudinal association between adolescent CRP levels and adult schizophrenia diagnosis indicates a potentially important role of inflammation in the pathogenesis of the illness, although the findings, based on a small number of cases, need to be interpreted with caution and require replication in other samples.

Abbreviations

CRP
C-reactive protein
OR
odds ratio
IL
interleukin
TNFα
tumour necrosis factor alpha
ALSPAC
Avon Longitudinal Study of Parents and Children
NFBC
Northern Finland Birth Cohort
AHA
American Heart Association
CDC
Centers for Disease Control and Prevention
FHDR
Finnish Hospital Discharge Register
ICD-10
International Classification of Diseases, 10th revision
NAPLS
North American Prodrome Longitudinal Study

Keywords

C-reactive protein
Inflammatory markers
Systemic inflammation
Schizophrenia
Psychotic disorders
Adult
Adolescent
Longitudinal study

Cited by (0)

1

Joint first authors.

2

Joint last authors.