Research has shown heart disease, strokes and deaths from lung conditions and cancer is associated with an inflammation marker in the blood.
Scientists believe increased levels of C-reactive protein (CRP) indicates a higher risk of a wide range of diseases.
The protein may act as a signpost pointing to underlying health problems, but is not thought to cause any illness itself.
CRP is produced by the liver and known to be a sensitive indicator of body-wide inflammation that can damage tissues.
Earlier research had indicated that the protein might be as good an indicator of heart attack risk as cholesterol levels.
Researchers have now taken a closer look at CRP by combining information from 54 long-term studies involving more than 160,000 people in 18 countries.
Pooling together data from different studies, known as meta-analysis, can reveal trends which would otherwise remain hidden.
The analysis revealed that CRP concentration was associated with the future risk of numerous conditions, including heart and artery disease, stroke, chronic lung disease and various cancers.
The study authors, led by Professor John Danesh, from Cambridge University, wrote in The Lancet medical journal online: "CRP concentration has continuous associations with the risk of coronary heart disease, ischaemic (cutting off blood supply) stroke, vascular mortality and death from several cancers and lung disease that are each of broadly similar size."