People with high concentrations of homocysteine, an amino acid in the blood, may have an increased risk of stroke, suggests a study published in this week’s issue of The Lancet (See pages 224, 232). Stroke is the third most common cause of death in developed countries. There are 125,000 cases of stroke in the UK each year and 60,000 deaths. Because treatment is limited, prevention through modification of risk factors such as high blood pressure and smoking is important. Observational studies measuring homocysteine concentrations in healthy individuals have found that, on average, those with high levels of homocysteine in their blood are more likely to have a stroke. But other factors that increase homocysteine concentration and stroke risk- such as smoking and socioeconomic class-may be responsible for the relationship observed in these studies, confounding the result.
