Rheumatoid arthritis can double and even triple a woman's risk of suffering a heart attack, a new study has found, suggesting that women with the painful autoimmune disorder should take aggressive measures to prevent heart disease.

Rheumatoid arthritis should now be recognised as a marker of increased heart attack risk, although it doesn't appear to increase risk of stroke, say authors of the study that appeared in the online edition of the American Heart Association journal Circulation.

Rheumatoid arthritis involves inflammation of the joint linings and internal organs. Coronary artery disease is increasingly being linked to inflammation. Some of the cells that can be found in inflamed joints also turn up in the plaques that build up inside artery linings. Methotrexate, one of the drugs used to treat rheumatoid arthritis, reduces joint inflammation and the risk of heart disease deaths.

"The association between inflammation and heart disease is strengthened with the findings of this study," said Dr Daniel H. Solomon, a rheumatologist at Brigham and Women's Hospital in Boston.

He and his colleagues said their work differed from previous analyses because they looked at generally healthy women – from the landmark Nurses Health Study, which has followed more than 120,000 women since 1976. The researchers identified 114,342 women ages 30 to 55 without heart disease or rheumatoid arthritis when the study began in 1976. They found 527 diagnoses of rheumatoid arthritis, 2,296 heart attacks and 1,326 strokes since the study was started.

Simply having rheumatoid arthritis doubled a woman's risk of heart attack, compared with healthy women; having it for at least a decade more than tripled heart attack risk.

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