C reactive protein and the risk of cardiovascular disease

Atherosclerosis is an inflammatory condition.1 Observational studies have consistently shown that the concentrations of several systemic markers of inflammation measurable in blood are related to the risk of developing atherosclerosis. Among these associations, that between C reactive protein (CRP) and coronary heart disease has been most intensively studied.2 In the linked study (doi:10.1136/bmj.d548), the C Reactive Protein Coronary Heart Disease Genetics Collaboration combines the power of genetics and meta-analysis to assess whether higher concentrations of CRP cause coronary heart disease⇓.3

High concentrations of CRP are seen in conditions such as bacterial sepsis, but the variation associated with the risk of coronary heart disease in epidemiological studies lies largely within the normal range for CRP. Statins lower CRP in addition to their effect on low density lipoprotein-cholesterol; the JUPITER trial showed that rosuvastatin substantially reduced cardiovascular events in apparently healthy people who did not have hyperlipidaemia (low density lipoprotein-cholesterol <3.4 mmol/L) but did have high concentrations of CRP (≥2.0 mg/L).4 Since this study, the place for CRP in informing decisions about primary prevention with statins has been hotly debated.5 6 However, a fundamental biological question—whether CRP itself predisposes to coronary heart disease, or whether it is an “innocent …