From the Guidelines
Elevated C-reactive protein (CRP) is primarily caused by inflammation or infection in the body, as supported by recent studies such as 1, which highlights the role of inflammation in chronic disease risk. When tissues are damaged or infected, the liver produces CRP as part of the immune response. Common causes include:
- Bacterial infections
- Viral infections
- Autoimmune disorders like rheumatoid arthritis or lupus
- Inflammatory bowel diseases such as Crohn's disease or ulcerative colitis
- Cardiovascular conditions including heart attacks and atherosclerosis Other factors that can raise CRP levels include:
- Obesity
- Smoking
- Lack of exercise
- Chronic stress
- Certain medications like hormone replacement therapy Some cancers may also trigger elevated CRP. The level of elevation often correlates with the severity of inflammation, with minor elevations (under 10 mg/L) potentially indicating chronic low-grade inflammation, while significant elevations (over 50 mg/L) typically suggest acute infection or severe inflammatory conditions, as noted in studies like 1 and 1. It's essential to note that CRP is a non-specific marker, meaning it indicates inflammation is present but doesn't identify the exact cause, so additional testing is usually needed to determine the underlying condition, as suggested by 1. Furthermore, recent research like 1 emphasizes the importance of nutrition in inflammation and CRP levels, highlighting the potential for dietary factors to influence CRP levels and chronic disease risk.
From the Research
Causes of Elevated C-Reactive Protein
- Infection is a major cause of elevated C-reactive protein (CRP) levels, with 55.1% of cases attributed to infection 2
- Rheumatologic diseases, such as rheumatoid arthritis (RA), are also associated with elevated CRP levels, with 7.5% of cases attributed to these conditions 2
- Other causes of elevated CRP levels include malignancy, drug reactions, and other inflammatory conditions 2
- Systemic inflammation, which is common in RA, can also lead to elevated CRP levels, and is associated with an increased risk of cardiovascular disease, diabetes, metabolic syndrome, pulmonary diseases, and depression 3
Conditions Associated with Elevated CRP Levels
- Rheumatoid arthritis (RA) is associated with elevated CRP levels, which can be used as a marker of systemic inflammation and disease activity 3, 4
- Cardiovascular disease is also associated with elevated CRP levels, with levels >3 mg/L and >10 mg/L indicating high and very high cardiovascular risk, respectively 5
- Infections, such as bacterial and viral infections, can cause elevated CRP levels, with higher levels indicating a greater likelihood of bacterial infection 2, 6
- Other conditions, such as malignancy and drug reactions, can also cause elevated CRP levels 2
CRP Levels and Disease Activity
- Elevated CRP levels are associated with increased disease activity in RA, and can be used to monitor treatment response 3
- CRP levels can also be used to differentiate between viral and bacterial infections, with higher levels indicating a greater likelihood of bacterial infection 6
- The relationship between CRP levels and disease activity is complex, and can be influenced by a variety of factors, including treatment and comorbidities 3, 4