These studies include the Physicians' Health Study, the Tromso Study from Norway, the Framingham Heart Study, and a meta-analysis of nearly 40 studies. Some studies indicate that persons with elevated homocysteine levels tend to also have other risk factors for heart disease, especially smoking, high blood pressure, and high blood cholesterol. So far, no clinical trial has been done to show that lowering homocysteine levels alters the progression of heart disease, or prevents heart attacks or strokes. Much more basic research must be done before scientists understand how an elevated homocysteine level affects the development and progression of heart disease. Homocysteine also may make blood more likely to clot by increasing the stickiness of blood platelets.
Clots can block blood flow, causing a heart attack or stroke.
Increased homocysteine may affect other substances involved in clotting too. However, none of theories has so far been proven. Individuals differ in their levels of homocysteine. Genetic factors help regulate the level of homocysteine in the blood. The level of homocysteine in the blood also is affected by the consumption of vitamins, especially folic acid, B6, and B12.