High circulating levels of a protein called mannan binding lectin (MBL), which prompts scavenger cells to remove various inflammatory agents, appear to reduce the risk of having a heart attack - especially for people with diabetes - Icelandic researchers report.

Although the protein was known to have potentially beneficial anti-inflammatory effects, the ability of MBL to ward off heart attacks had not be studied before, according to the report in The Journal of Experimental Medicine.

Dr. Helgi Valdimarsson, from Landspitali-University Hospital in Reykjavik, and colleagues analyzed data from the Reykjavik study, which includes 20,000 subjects recruited starting in 1967.

Among about a thousand 70-year-old participants from the original enrollment, high MBL levels were linked to a 36 percent reduced risk of heart attack compared with lower levels.

To confirm this finding, the researchers followed another 1300 middle-age subjects. In this analysis, the link between high MBL levels and a reduced likelihood of having a heart attack was not as strong as in the original group and was not significant from a statistical standpoint for the whole group, or for subsets of smokers or those with high blood pressure.

However, the analysis did show that high levels were tied to greatly reduced risks for a heart attack among subjects with diabetes or High cholesterol. In fact, people with diabetes with high MBL levels had a risk on par with non-diabetic subjects.

For people with diabetes, the team concludes, measuring MBL “might actually aid in the evaluation of the need for preventive treatment” for heart disease.

SOURCE: Journal of Experimental Medicine, January 3, 2005.