Cited by 199Genetic Associations and EpidemiologyAdipokines, Inflammation, and Metabolic DiseasesLipoproteins and Cardiovascular Health

Investigating the Causal Relationship of C-Reactive Protein with 32 Complex Somatic and Psychiatric Outcomes: A Large-Scale Cross-Consortium Mendelian Randomization Study

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Prins, Bram. P., Abbasi, Ali, Wong, Anson, Vaez, Ahmad, Nolte, Ilja, Franceschini, Nora, Stuart, Philip E., Guterriez Achury, Javier +53 more·2016·PLOS Medicine

Abstract

BACKGROUND: C-reactive protein (CRP) is associated with immune, cardiometabolic, and psychiatric traits and diseases. Yet it is inconclusive whether these associations are causal. METHODS AND FINDINGS: We performed Mendelian randomization (MR) analyses using two genetic risk scores (GRSs) as instrumental variables (IVs). The first GRS consisted of four single nucleotide polymorphisms (SNPs) in the CRP gene (GRSCRP), and the second consisted of 18 SNPs that were significantly associated with CRP levels in the largest genome-wide association study (GWAS) to date (GRSGWAS). To optimize power, we used summary statistics from GWAS consortia and tested the association of these two GRSs with 32 complex somatic and psychiatric outcomes, with up to 123,865 participants per outcome from populations of European ancestry. We performed heterogeneity tests to disentangle the pleiotropic effect of IVs. A Bonferroni-corrected significance level of less than 0.0016 was considered statistically significant. An observed p-value equal to or less than 0.05 was considered nominally significant evidence for a potential causal association, yet to be confirmed. The strengths (F-statistics) of the IVs were 31.92-3,761.29 and 82.32-9,403.21 for GRSCRP and GRSGWAS, respectively. CRP GRSGWAS showed a statistically significant protective relationship of a 10% genetically elevated CRP level with the risk of schizophrenia (odds ratio [OR] 0.86 [95% CI 0.79-0.94]; p < 0.001). We validated this finding with individual-level genotype data from the schizophrenia GWAS (OR 0.96 [95% CI 0.94-0.98]; p < 1.72 × 10-6). Further, we found that a standardized CRP polygenic risk score (CRPPRS) at p-value thresholds of 1 × 10-4, 0.001, 0.01, 0.05, and 0.1 using individual-level data also showed a protective effect (OR < 1.00) against schizophrenia; the first CRPPRS (built of SNPs with p < 1 × 10-4) showed a statistically significant (p < 2.45 × 10-4) protective effect with an OR of 0.97 (95% CI 0.95-0.99). The CRP GRSGWAS showed that a 10% increase in genetically determined CRP level was significantly associated with coronary artery disease (OR 0.88 [95% CI 0.84-0.94]; p < 2.4 × 10-5) and was nominally associated with the risk of inflammatory bowel disease (OR 0.85 [95% CI 0.74-0.98]; p < 0.03), Crohn disease (OR 0.81 [95% CI 0.70-0.94]; p < 0.005), psoriatic arthritis (OR 1.36 [95% CI 1.00-1.84]; p < 0.049), knee osteoarthritis (OR 1.17 [95% CI 1.01-1.36]; p < 0.04), and bipolar disorder (OR 1.21 [95% CI 1.05-1.40]; p < 0.007) and with an increase of 0.72 (95% CI 0.11-1.34; p < 0.02) mm Hg in systolic blood pressure, 0.45 (95% CI 0.06-0.84; p < 0.02) mm Hg in diastolic blood pressure, 0.01 ml/min/1.73 m2 (95% CI 0.003-0.02; p < 0.005) in estimated glomerular filtration rate from serum creatinine, 0.01 g/dl (95% CI 0.0004-0.02; p < 0.04) in serum albumin level, and 0.03 g/dl (95% CI 0.008-0.05; p < 0.009) in serum protein level. However, after adjustment for heterogeneity, neither GRS showed a significant effect of CRP level (at p < 0.0016) on any of these outcomes, including coronary artery disease, nor on the other 20 complex outcomes studied. Our study has two potential limitations: the limited variance explained by our genetic instruments modeling CRP levels in blood and the unobserved bias introduced by the use of summary statistics in our MR analyses. CONCLUSIONS: Genetically elevated CRP levels showed a significant potentially protective causal relationship with risk of schizophrenia. We observed nominal evidence at an observed p < 0.05 using either GRSCRP or GRSGWAS-with persistence after correction for heterogeneity-for a causal relationship of elevated CRP levels with psoriatic osteoarthritis, rheumatoid arthritis, knee osteoarthritis, systolic blood pressure, diastolic blood pressure, serum albumin, and bipolar disorder. These associations remain yet to be confirmed. We cannot verify any causal effect of CRP level on any of the other common somatic and neuropsychiatric outcomes investigated in the present study. This implies that interventions that lower CRP level are unlikely to result in decreased risk for the majority of common complex outcomes.

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Authors
Prins, B. P., Abbasi, A., Wong, A., Vaez, A., Nolte, I., Franceschini, N., Stuart, P. E., Guterriez Achury, J., Mistry, V., Bradfield, J. P., Valdes, A. M., Bras, J., Shatunov, A., PAGE Consortium, International Stroke Genetics Consortium, Systemic Sclerosis consortium, Treat OA consortium, DIAGRAM Consortium, CARDIoGRAMplusC4D Consortium, ALS consortium, International Parkinson’s Disease Genomics Consortium, Autism Spectrum Disorder Working Group of the Psychiatric Genomics Consortium, CKDGen consortium, GERAD1 Consortium, International Consortium for Blood Pressure, Schizophrenia Working Group of the Psychiatric Genomics Consortium, Inflammation Working Group of the CHARGE Consortium, Lu, C., Han, B., Raychaudhuri, S., Bevan, S., Mayes, M. D., Tsoi, L. C., Evangelou, E., Nair, R. P., Grant, S. F. A., Polychronakos, C., Radstake, T. R. D., van Heel, D. A., Dunstan, M. L., Wood, N. W., Al-Chalabi, A., Dehghan, A., Hakonarson, H., Markus, H. S., Elder, J. T., Knight, J., Arking, D. E., Spector, T. D., Koeleman, B. P. C., van Duijn, C. M., Martin, J., Morris, A. P., Weersma, R. K., Wijmenga, C., Munroe, P. B., Perry, J. R. B., Pouget, J. G., Jamshidi, Y., Snieder, H., & Alizadeh, B. Z.
Affiliations
  • University Medical Center Groningen (NL)
  • University of Ottawa (CA)
  • Isfahan University of Medical Sciences (IR)
  • University of North Carolina at Chapel Hill (US)
  • University of Michigan (US)
  • Queen Mary University of London (GB)
  • Children's Hospital of Philadelphia (US)
  • University of Nottingham (GB)
  • King's College London (GB)
  • Boston University (US)
  • Broad Institute (US)
  • University of Cambridge (GB)
  • The University of Texas Health Science Center at Houston (US)
  • McGill University Health Centre (CA)
  • University Medical Center Utrecht (NL)
  • Cardiff University (GB)
  • UCL Queen Square Institute of Neurology (GB)
  • Erasmus MC (NL)
  • Centre for Addiction and Mental Health (CA)
  • Johns Hopkins University (US)
  • Consejo Superior de Investigaciones Científicas (ES)
  • Centre for Human Genetics (GB)
  • St George's, University of London (GB)
Corresponding author
  • Prins, Bram. P.
  • Alizadeh, Behrooz Z.
Venue
PLOS Medicine
Published
2016-06-21
Volume
13
Issue
6
Pages
e1001976
ISSN
  • 1549-1277 (ISSN-L)
  • 1549-1676
OpenAlex
W2474672982
Cited by
199
References
117
Citations by year
2026: 10 · 2025: 20 · 2024: 24 · 2023: 19 · 2022: 24 · 2021: 18 · 2020: 16 · 2019: 22 · 2018: 24 · 2017: 17 · 2016: 5
FWCI
18.29
Type
journal article
Language
en
Open access
Locations
  • PLoS Medicine (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Repository@Nottingham (University of Nottingham) (publishedVersion, cc-by)
  • Research Explorer (The University of Manchester) (publishedVersion, cc-by)
  • EUR Research Repository (Erasmus University Rotterdam) (publishedVersion, other-oa)
  • Lancaster EPrints (Lancaster University) (acceptedVersion)
  • Lincoln Repository (University of Lincoln) (acceptedVersion)
  • ORCA Online Research @Cardiff (Cardiff University) (acceptedVersion)
  • St George's Online Research Archive (St George's University of London) (acceptedVersion)
  • Repository@Nottingham (University of Nottingham) (submittedVersion, cc-by)
  • Apollo (University of Cambridge) (submittedVersion, cc-by)
  • Digital Access to Scholarship at Harvard (DASH) (Harvard University) (submittedVersion, cc-by)
  • EUR Research Repository (Erasmus University Rotterdam) (submittedVersion, other-oa)
  • RePub (Erasmus University Rotterdam) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Utrecht University Repository (Utrecht University) (submittedVersion, other-oa)
  • UCL Discovery (University College London) (submittedVersion)
  • Figshare (submittedVersion, cc-by)
  • Research Portal (King's College London) (submittedVersion, cc-by)
  • Site cant be reached (submittedVersion)
  • University of Groningen research database (University of Groningen / Centre for Information Technology) (submittedVersion, cc-by)
  • PuSH - Publication Server of Helmholtz Zentrum München (submittedVersion)
  • Queen Mary Research Online (Queen Mary University of London) (submittedVersion)
  • Seoul National University Open Repository (Seoul National University) (submittedVersion)
  • Spiral (Imperial College London) (submittedVersion, other-oa)
  • NOVA (University of Newcastle Australia) (submittedVersion, cc-by)
  • Apollo (cc-by)
Funders
  • Consejería Economía, Innovación, Ciencia y Empleo, Junta de Andalucia (CTS-4977)
  • Economic and Social Research Council (ES/H029745/1)
  • The Wellcome Trust (WT098051)
  • NWO (825.13.004, 016.136.308)
  • Medical Research Council UK (MC-U106179471)
  • Wellcome Trust Senior Fellow in Basic Biomedical Science (WT098017)
  • National Institutes of Health (R01AR042742, R01AR054966, R01AR050511, R01 AR055258, R01 HL076784, R01 AG028321, 1RO1 HL64753, HHSN268201500001I)
  • Spanish Ministry of Economy and Competitiveness (SAF2012-34435)
  • National Institute of Diabetes and Digestive and Kidney Diseases (DP3 DK085708)
  • Juvenile Diabetes Research Foundation International (JDRF)
  • Broad Foundation (N01-HC 25195)
  • Wellcome Trust (076113)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
  • Health Sciences › Medicine › Epidemiology › Adipokines, Inflammation, and Metabolic Diseases
  • Health Sciences › Medicine › Surgery › Lipoproteins and Cardiovascular Health
Keywords
C-reactive protein, schizophrenia, causal inference, polygenic risk score, mental health outcomes, pleiotropy, inflammation, protective effect, European ancestry populations, Mendelian randomization
MeSH terms
Mental Disorders, C-Reactive Protein, Genotype, Heart Diseases, Humans, Immune System Diseases, Metabolic Diseases, Polymorphism, Single Nucleotide, Genome-Wide Association Study, Mendelian Randomization Analysis

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