Effect of hyperhomocysteinemia and methylenetetrahydrofolate reductase 677C --> T mutation in venous thromboembolism risk of young adults.
BACKGROUND AND OBJECTIVE: To investigate whether hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) 677C --> T mutation are associated with venous thromboembolism in young Spanish adults. PATIENTS AND METHOD: One hundred adult patients younger than 50 years and 177 controls with similar age and gender. RESULTS: Hyperhomocysteinemia was present in 21% of the patients and 3.3% of the controls (p < 0.001), and MTHFR 677C --> T mutation was found in 25 and 14.7%, respectively (p = 0.03). Odds ratio (OR) for thromboembolism in hyperhomocysteinemic patients was 7.5 (95% CI, 2.9-19.2; p < 0.001), and in patients with MTHFR 677C --> T mutation the OR was 1.9 (95% CI, 1.1-3.5; p = 0.03). In a subgroup of 76 patients without other thrombogenic factors, thromboembolism persisted associated with hyperhomocysteinemia, yet an association with MTHFR 677C --> T mutation was not confirmed. CONCLUSIONS: Hyperhomocysteinemia, but not MTHFR 677C --> T mutation, is a risk factor for venous thromboembolism in young adults without other thrombogenic factors.