Homocysteine: an emerging age-related cardiovascular risk factor.

Homocysteine is an intermediate formed during the metabolism of the essential sulfur containing amino acid methionine. Homocysteine concentration rises progressively with age in men and women, making it an important risk factor for cardiovascular disease. The causes are still under study, but likely culprits include clinical or subclinical folate and B vitamin deficiencies and possibly renal dysfunction. The association between adverse cardiovascular events and plasma homocysteine persists in older populations. In women, homocysteine levels increase after menopause and may be related to decreased estrogen concentrations. Folic acid supplementation decreases homocysteine concentration, but coadministration of vitamin B12 may be needed to prevent irreversible neurologic damage.