Efficacy of B vitamins in lowering homocysteine in older men: maximal effects for those with B12 deficiency and hyperhomocysteinemia.
OBJECTIVE
A higher plasma concentration of total homocysteine (tHcy) is associated with a greater risk of cardiovascular events. Previous studies, largely in younger individuals, have shown that B vitamins lowered tHcy by substantial amounts and that this effect is greater in people with higher tHcy and lower folate levels.


METHODS
We undertook a 2-year, double-blind, placebo-controlled, randomized trial in 299 men aged > or =75 years, comparing treatment with a daily tablet containing 2 mg of folate, 25 mg of B6, and 400 microg of B12 or placebo. The study groups were balanced regarding age (mean+/-SD, 78.9+/-2.8 years), B vitamins, and tHcy at baseline.


RESULTS
Among the 13% with B12 deficiency, the difference in mean changes in treatment and control groups for tHcy was 6.74 micromol/L (95% CI, 3.94 to 9.55 micromol/L) compared with 2.88 micromol/L (95% CI, 0.07 to 5.69 micromol/L) for all others. Among the 20% with hyperhomocysteinaemia, the difference between mean changes in treatment and control groups for men with high plasma tHcy compared with the rest of the group was 2.8 micromol/L (95% CI, 0.6 to 4.9 micromol/L). Baseline vitamin B12, serum folate, and tHcy were significantly associated with changes in plasma tHcy at follow-up (r=0.252, r=0.522, and r=-0.903, respectively; P=0.003, <0.001, and <0.001, respectively) in the vitamin group.


CONCLUSIONS
The tHcy-lowering effect of B vitamins was maximal in those who had low B12 or high tHcy levels. Community-dwelling older men, who are likely to be deficient in B12 or have hyperhomocysteinemia, may be most likely to benefit from treatment with B vitamins.
Flicker
Leon
L
School of Medicine and Pharmacology, University of Western Australia, Perth, Australia. leonflic@cyllene.uwa.edu.au
Vasikaran
Samuel D
SD
Thomas
Jenny
J
Acres
John M
JM
Norman
Paul
P
Jamrozik
Konrad
K
Hankey
Graeme J
GJ
Almeida
Osvaldo P
OP
D000368:Aged; D019587:Dietary Supplements; D004311:Double-Blind Method; D005492:Folic Acid / Q000494:pharmacology; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000628:therapy*; D008297:Male; D010919:Placebos; D013997:Time Factors; D016896:Treatment Outcome; D014805:Vitamin B 12 / Q000494:pharmacology; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000628:therapy*; D014803:Vitamin B Complex / Q000494:pharmacology*
D010919:Placebos; D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid; D014805:Vitamin B 12