Arthritis drugs could provide a new approach to treating heart disease by targeting inflammation, research suggests.
Two new genetic studies have found a clear causal link between a specific inflammation signalling pathway and the development of coronary heart disease (CHD).
The evidence indicates that heart disease can be tackled using certain anti-inflammatory drugs.
One such drug, tocilizumab, is already commonly used to treat rheumatoid arthritis, an auto-immune disease.
Inflammation is a basic immune response to infection or injury which can become too strong and end up damaging body tissue.
Experts have long suspected that it plays a role in heart disease by contributing to artherosclerosis, the build-up of hard deposits on artery walls, but until now no causal link involving a specific inflammatory pathway has been found.
The new research, published online in The Lancet medical journal, focused on an inflammatory signalling protein called interleukin-6 receptor (IL6R).
Combined data from more than 2,000 people taking part in 82 studies found that one variant of the IL6R gene protected against heart disease.
The mutation dampened the effects of inflammation, and each of two copies of the gene inherited reduced the risk of heart disease by 3.4%.
A separate "meta-analysis" pooling the results of 40 studies involving 133,449 participants showed that the IL6R variant and tocilizumab had similar effects.
Dr Adam Butterworth, from Cambridge University, who co-led the first study, said: "Typically, it can take many years to make safe and effective drugs to target new disease pathways. However, in this case, drugs have been previously developed due to this pathway's involvement in auto-immune disease.
"In fact, one such drug, tocilizumab, is already used for treating arthritis, and might therefore be a viable drug for preventing heart disease."
Heart disease claims 200,000 lives each year in the UK, accounting for one in three deaths.
Professor Jeremy Pearson, associate medical director at the British Heart Foundation (BHF), which co-funded the research, said: "These two powerful complementary studies provide very strong evidence that new medicines, which reduce inflammation by blocking the IL-6 receptor, could be a powerful tool in helping to combat heart disease.
"A drug taken by some people with rheumatoid arthritis, called tocilizumab, already works in this way. But it's not ideal because it appears to increase cholesterol levels so further research is needed to find additional drugs that target this protein."