Elevated plasma homocysteine and low vitamin B-6 status in nonsupplementing older women with rheumatoid arthritis.
OBJECTIVE
The purpose of this study was to determine if nonsupplementing older women (aged >or=55 years) with rheumatoid arthritis had higher plasma homocysteine and lower B-vitamin status compared to healthy controls. Elevated plasma homocysteine, a risk factor for cardiovascular disease, may help explain why individuals with rheumatoid arthritis have an increased risk of cardiovascular disease.


METHODS
Older, free-living women were classified as rheumatoid arthritis (n=18) or healthy control (n=33). Participants were not using B-vitamin supplements. Fasting blood samples were measured for pyridoxal 5'phosphate (PLP) (the metabolically active coenzyme form of vitamin B-6), folate, red blood cell folate, vitamin B-12, transcobalamin II, homocysteine, C-reactive protein, and lipid concentrations. Participants completed 7-day weighed food records, the Stanford Health Assessment Questionnaire (HAQ), and a visual analog pain scale.


RESULTS
PLP concentrations were lower in the rheumatoid arthritis vs healthy control participants (4.93+/-3.85 vs 11.35+/-7.11 ng/mL [20+/-16 vs 46+/-29 nmol/L]; P<0.01) whereas plasma homocysteine was higher in the rheumatoid arthritis group (1.63+/-0.74 vs 1.15+/-0.38 mg/L [12.1+/-5.5 vs 8.5+/-2.8 micromol/L]; P=0.02). Red blood cell folate concentrations were lower in the rheumatoid arthritis vs healthy control participants [414+/-141 vs 525+/-172 ng/mL [938+/-320 vs 1,190+/-390 nmol/L]; P=0.02). No significant differences were found for plasma folate, vitamin B-12, and transcobalamin II. An inverse correlation was found between PLP concentrations and the HAQ disability index (r=-0.37; P<0.01). A positive correlation was found between homocysteine concentrations and the HAQ disability index (r=0.36; P=0.01). Total cholesterol and low-density lipoprotein cholesterol levels were lower in the rheumatoid arthritis group (cholesterol 191+/-43 vs 218+/-33 mg/dL [4.95+/-1.11 vs 5.65+/-0.85 mmol/L]; P=0.02; low-density lipoprotein cholesterol 110+/-36 vs 137+/-29 mg/dL [2.85+/-0.93 vs 3.55+/-0.75 mmol/L]; P<0.01). No significant differences were seen between groups for protein (g/day), fat (g/day), cholesterol (mg/day), folate (microg/day), vitamin B-12 (microg/day), and vitamin B-6 (mg/day) dietary intakes.


CONCLUSIONS
Poor vitamin B-6 status and elevated plasma homocysteine concentrations were seen in older women with rheumatoid arthritis compared to healthy controls and may contribute to their increased risk of cardiovascular disease.
Woolf
Kathleen
K
Arizona State University Department of Nutrition, 6950 E Williams Field Rd, Mesa, AZ 85212, USA. kathleen.woolf@asu.edu
Manore
Melinda M
MM
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000503:physiopathology; D002097:C-Reactive Protein / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D015930:Diet Records; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005492:Folic Acid / Q000032:analysis / Q000097:blood; D006710:Homocysteine / Q000097:blood; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D008055:Lipids / Q000097:blood; D008875:Middle Aged; D009752:Nutritional Status; D011732:Pyridoxal Phosphate / Q000097:blood / Q000172:deficiency; D012307:Risk Factors; D014155:Transcobalamins / Q000378:metabolism; D014805:Vitamin B 12 / Q000097:blood; D025101:Vitamin B 6 / Q000097:blood; D026681:Vitamin B 6 Deficiency / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D014803:Vitamin B Complex / Q000097:blood
D008055:Lipids; D014155:Transcobalamins; D006710:Homocysteine; D014803:Vitamin B Complex; D011732:Pyridoxal Phosphate; D025101:Vitamin B 6; D002097:C-Reactive Protein; D005492:Folic Acid; D014805:Vitamin B 12