C-reactive protein (CRP)

Summary

• CRP is a blood marker of inflammation. It goes up when your immune system is activated (for example by an infection, injury, or a flare of a chronic condition).
• Higher long-term CRP is linked to higher risk of death from all causes, usually in a dose-response pattern (risk rises as CRP rises).
• In a large meta-analysis of cohort studies, compared with low CRP, moderate CRP was linked to about 30% higher all-cause mortality risk, and high CRP to about 75% higher risk.
• In a long UK Biobank analysis using a systemic inflammation score (which includes CRP), higher inflammation was associated with several years shorter estimated life expectancy.

Factor description

This factor measures the concentration of C-reactive protein in your blood, usually reported in mg/L.

CRP is made mainly by the liver and rises when there is inflammation somewhere in the body. It is not specific to one disease.

CRP can be measured as:

• Standard CRP (useful for larger rises, often seen with infections or active inflammation)
• High-sensitivity CRP (hs-CRP), which can detect smaller differences often seen in low-grade, chronic inflammation

Impact on all-cause mortality

1. CRP is a strong signal of ongoing biological stress and immune activation
   CRP often reflects processes that raise mortality risk over time, such as chronic low-grade inflammation, metabolic risk, vascular inflammation, and hidden or developing disease. Because it is non-specific, it acts more like a risk flag than a diagnosis.

2. Large studies consistently show higher CRP predicts higher mortality
   Across general population cohorts and meta-analyses, higher CRP is associated with higher all-cause mortality risk, even after adjusting for many traditional risk factors. The relationship is commonly dose-dependent (gradual rise in risk across higher CRP groups).

3. Part of the risk is likely shared causes, not CRP itself
   CRP often rises with smoking, excess body fat, poor fitness, uncontrolled blood pressure or blood sugar, chronic infections, autoimmune disease, and other inflammatory conditions. So lowering CRP usually means addressing root causes, not treating the number.

4. Life expectancy impact can be meaningful at the population level
   In UK Biobank work using a systemic inflammation score that includes CRP, higher inflammation was associated with a reduction in estimated life expectancy by a few years (the exact estimate varied by age and sex).

Patterns

Who tends to have higher CRP (and why this matters):

• People with recent infection, injury, surgery, or vaccination can have temporarily higher CRP (not a stable baseline).
• Chronic conditions commonly linked to higher CRP include obesity, type 2 diabetes, chronic kidney disease, autoimmune disease, chronic lung disease, and some cancers.
• Lifestyle patterns linked to higher CRP often include smoking, low physical activity, poor cardiorespiratory fitness, poor sleep, and diets low in whole plant foods.
• CRP levels often correlate with socioeconomic disadvantage and higher overall disease burden.

A short history fact (useful for the article):

• CRP was discovered in 1930.
• Practical clinical measurement became more widely usable after immunological testing methods matured (for example latex agglutination testing published in the 1950s).
• High-sensitivity CRP later enabled research and risk stratification at much lower CRP ranges relevant to chronic disease risk.

KamaLama scoring

Scoring logic
CRP behaves like a dose-response risk marker in most large studies: higher baseline CRP is generally linked to higher all-cause mortality risk. KamaLama uses a stepwise scoring rule based on common clinical and epidemiological cut-points for low-grade inflammation, while recognising that CRP is non-specific and should be interpreted as a baseline pattern (not a one-off spike).

Practical tips

• Re-test if you were recently ill: if you had a cold, flu, dental infection, injury, or surgery recently, ask your clinician whether repeating CRP after recovery makes sense (baseline matters more than a single spike).
• If CRP is persistently above 3 mg/L, treat it as a root cause search prompt: sleep, body weight, smoking, physical activity, alcohol, oral health, and chronic conditions are common drivers.
• Build weekly activity (a realistic target is consistency, not perfection): regular aerobic exercise and strength training are both linked to lower inflammation markers over time.
• If you smoke, quitting is one of the strongest ways to reduce inflammation-related risk.
• Consider a Mediterranean-style pattern: more vegetables, legumes, whole grains, nuts, fish, and olive oil; fewer ultra-processed foods.
• Do a simple oral-health audit: gum disease and chronic dental inflammation can raise inflammatory markers.
• Work with a clinician if CRP is high or stays high, especially above 10 mg/L, or if you have symptoms (this is about finding the cause, not guessing).

References

Authoritative safety evaluations / guidelines (if applicable)

• Centers for Disease Control and Prevention (CDC) and American Heart Association (AHA). 2003. Markers of Inflammation and Cardiovascular Disease: Application to Clinical and Public Health Practice (Circulation). https://www.ahajournals.org/doi/10.1161/01.cir.0000052939.59093.45
• MedlinePlus. 2025. C-Reactive Protein (CRP) Test (patient overview). https://medlineplus.gov/lab-tests/c-reactive-protein-crp-test/
• Mayo Clinic. 2025. C-reactive protein test (patient overview). https://www.mayoclinic.org/tests-procedures/c-reactive-protein-test/about/pac-20385228

Peer-reviewed / indexed research

• Singer JM, Plotz CM, Pader E, Elster SK. 1957. The latex-fixation test. III. Agglutination test for C-reactive protein and comparison with the capillary precipitin method (American Journal of Clinical Pathology). https://doi.org/10.1093/ajcp/28.6.611
• Pepys MB, Hirschfield GM. 2003. C-reactive protein: a critical update (Journal of Clinical Investigation). https://www.jci.org/articles/view/18921
• Ridker PM. 2009. C-reactive protein: eighty years from discovery to emergence as a major risk marker for cardiovascular disease (Clinical Chemistry). https://doi.org/10.1373/clinchem.2008.119214
• Kaptoge S, Di Angelantonio E, Lowe G, et al. 2010. C-reactive protein concentration and risk of coronary heart disease, stroke, and mortality: an individual participant meta-analysis (The Lancet). https://doi.org/10.1016/S0140-6736(09)61717-7
• Ahmadi-Abhari S, Luben RN, Wareham NJ, Khaw KT. 2013. Seventeen year risk of all-cause and cause-specific mortality associated with C-reactive protein, fibrinogen and leukocyte count in men and women: the EPIC-Norfolk study (European Journal of Epidemiology). https://doi.org/10.1007/s10654-013-9819-6
• Ni P, Yu M, Zhang R, et al. 2020. Dose-response association between C-reactive protein and risk of all-cause and cause-specific mortality: a systematic review and meta-analysis of cohort studies (Annals of Epidemiology). https://doi.org/10.1016/j.annepidem.2020.07.005
• Liu SJ, et al. 2024. The association of circulating systemic inflammation with premature death and the protective role of the Mediterranean diet: a large prospective cohort study of UK Biobank (BMC Public Health). https://doi.org/10.1186/s12889-024-18888-x
• Kushner I. 2023. C-reactive protein – My perspective on its first half century, 1930–1982 (Frontiers in Immunology). https://doi.org/10.3389/fimmu.2023.1150103