title: Age- and gender-specific reference intervals for total homocysteine and methylmalonic acid in plasma before and after vitamin supplementation.
abstract: We present reference intervals for total homocysteine and methylmalonic acid in plasma based on samples from 126 women (ages 20-85 years, median 49 years) and 109 men (ages 20-84 years, median 50 years). The central 0.95 interval for methylmalonic acid was 0.08-0.28 micromol/L. Supplementation with cyanocobalamin caused a nonsignificant decrease in methylmalonic acid. Supplementation with folic acid caused a decrease in homocysteine concentrations, with data analysis identifying two significantly different clusters: 182 subjects with the lowest initial concentrations (7.76 +/- 1.54 micromol/L, mean +/- SD) and the smallest decrease (1.26 +/- 0.96 micromol/L), and 53 subjects with the highest initial concentrations (12.33 +/- 2.04 micromol/L) and greatest decrease (4.14 +/- 1.32 micromol/L). We argue in favor of the age- and gender-specific central 0.95 intervals obtained for the 182 subjects before being supplemented with folic acid: 4.6-8.1 micromol/L for subjects at <30 years; 4.5-7.9 micromol/L for women, ages 30-59 years; 6.3-11.2 micromol/L for men, ages 30-59 years; and 5.8-11.9 micromol/L for subjects at >60 years.
authors.affiliation: Department of Clinical Biochemistry, Aarhus University Hospital at Skejby, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Rasmussen
authors.forename: J
authors.initials: J
authors.lastname: Møller
authors.forename: M
authors.initials: M
authors.lastname: Lyngbak
authors.forename: A M
authors.initials: AM
authors.lastname: Pedersen
authors.forename: L
authors.initials: L
authors.lastname: Dybkjaer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood*; D008875:Middle Aged; D012016:Reference Values; D012727:Sex Characteristics; D014805:Vitamin B 12 / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins; D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; D014805:Vitamin B 12