5,10 methylenetetrahydrofolate reductase (FADH2) Adult 6 Humans 6 Middle Aged 6 adult 6 article 6 controlled study 6 homocysteine 6 human 6 priority journal 6 Aged 4 DNA polymorphism 4 Factor V Leiden 4 Female 4 Homocysteine 4 Male 4 Methylenetetrahydrofolate Reductase (NADPH2) 4 Prothrombin 4 Thrombophilia 4 activated protein C resistance 4 aged 4 blood clotting factor 5 Leiden 4 disease association 4 female 4 hyperhomocysteinemia 4 major clinical study 4 male 4 phospholipid antibody 4 protein C 4 protein S 4