Interactions between plasma concentrations of folate and markers of vitamin B(12) status with cognitive performance in elderly people not exposed to folic acid fortification: the Hordaland Health Study.
A combination of high folate with low vitamin B12 plasma status has been associated with cognitive impairment in a population exposed to mandatory folic acid fortification. The objective of the present study was to examine the interactions between plasma concentrations of folate and vitamin B12 markers in relation to cognitive performance in Norwegian elderly who were unexposed to mandatory or voluntary folic acid fortification. Cognitive performance was assessed by six cognitive tests in 2203 individuals aged 72-74 years. A combined score was calculated using principal component analysis. The associations of folate concentrations, vitamin B12 markers (total vitamin B12, holotranscobalamin (holoTC) and methylmalonic acid (MMA)) and their interactions in relation to cognitive performance were evaluated by quantile regression and least-squares regression, adjusted for sex, education, apo-ɛ4 genotype, history of CVD/hypertension and creatinine. Cross-sectional analyses revealed an interaction (P= 0·009) between plasma concentrations of folate and vitamin B12 in relation to cognitive performance. Plasma vitamin B12 concentrations in the lowest quartile ( < 274 pmol/l) combined with plasma folate concentrations in the highest quartile (>18·5 nmol/l) were associated with a reduced risk of cognitive impairment compared with plasma concentrations in the middle quartiles of both vitamins (OR 0·22, 95 % CI 0·05, 0·92). The interaction between folate and holoTC or MMA in relation to cognitive performance was not significant. In conclusion, this large study population unexposed to mandatory folic acid fortification showed that plasma folate, but not plasma vitamin B12, was associated with cognitive performance. Among the elderly participants with vitamin B12 concentrations in the lower range, the association between plasma folate and cognitive performance was strongest.
Division of Human Nutrition, Wageningen University, PO Box 8129, 6700 EV, Wageningen, The Netherlands.
Esmée L
EL
Doets
Section for Pharmacology, Department of Clinical Science, University of Bergen, Bergen, Norway.
Per M
PM
Ueland
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Grethe S
GS
Tell
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Stein Emil
SE
Vollset
Section for Cardiology, Department of Clinical Science, University of Bergen, Bergen, Norway.
Ottar K
OK
Nygård
Division of Human Nutrition, Wageningen University, PO Box 8129, 6700 EV, Wageningen, The Netherlands.
Pieter
P
Van't Veer
Division of Human Nutrition, Wageningen University, PO Box 8129, 6700 EV, Wageningen, The Netherlands.
Lisette C P G M
LC
de Groot
Department of Nutrition, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
Eha
E
Nurk
Department of Nutrition, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
Helga
H
Refsum
Department of Pharmacology, Oxford Project to Investigate Memory and Ageing (OPTIMA), University of Oxford, Oxford, UK.
A David
AD
Smith
Section for Pharmacology, Department of Clinical Science, University of Bergen, Bergen, Norway.
Simone J P M
SJ
Eussen
D000368:Aged; D015415:Biomarkers / Q000097:blood*; D003072:Cognition Disorders / Q000097:blood*; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood*; D005527:Food, Fortified; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood; D009664:Norway; D009752:Nutritional Status; D014155:Transcobalamins / Q000032:analysis; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000150:complications*
D015415:Biomarkers; D014155:Transcobalamins; D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; D014805:Vitamin B 12