Emerging Risk Factors

      Three of the most important, emerging risk factors under investigation by Framingham researchers are:

• Homocysteine -- Framingham investigations indicate that high levels of this amino acid may contribute to heart disease, stroke, and a reduced flow of blood to the hands and feet.   Researchers believe that homocysteine may contribute to the buildup of fatty substances in the arteries, increase the stickiness of blood platelets (clotting), and make blood vessels less flexible, less able to widen to permit increased blood flow.   Levels of the amino acid are related partly to a genetic mechanism and diet.   The good news is that diet, especially one high in folic acid and B vitamins, favorably affects the levels of homocysteine.
  
  
• Lp(a) -- Low density lipoprotein (LDL) carries most of the disease promoting cholesterol throughout the bloodstream.   There also are other lipoproteins associated with LDL.   One of these, Lp(a), is now thought to be a risk factor for early heart disease.   Unlike LDL, Lp(a) does not appear to promote fatty buildup in the arteries.   Instead, its damage may come from preventing the breakup of clots.
  
  
• Infectious Agents -- Viruses and other infectious agents may harm blood vessel walls, starting the atherosclerotic process.   Framingham researchers are investigating whether cytomegalovirus (CMV), chlamydia, and H. pylori, a bacterium that causes stomach ulcers, play a role in damaging healthy blood vessels.
  

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