High prevalence of hyperhomocysteinemia related to folate deficiency and the 677C-->T mutation of the gene encoding methylenetetrahydrofolate reductase in coastal West Africa.
BACKGROUND
Moderate hyperhomocysteinemia is a risk for neural tube defect and neurodegenerative and vascular diseases and has nutritional, metabolic, and genetic determinants. Its prevalence in sub-Saharan Africa remains unknown.


OBJECTIVE
Our goal was to evaluate the prevalence of hyperhomocysteinemia and the influence of nutritional, metabolic, and genetic determinants in savanna and coastal regions of Togo and Benin.


METHODS
Volunteers were recruited from coastal (C groups; n = 208) and savanna (S group; n = 68) regions. Vitamin B-12, folate, total homocysteine (tHcy), cystatin C (a marker of glomerular filtration), and inflammatory and nutritional protein markers were measured in plasma, and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A--> C polymorphisms and the methionine synthase 2756A-->G polymorphism were examined in genomic DNA.


RESULTS
Moderate hyperhomocysteinemia (tHcy > 15 micromol/L) was recorded in 62.3% and 29.4% of the subjects from the coast and savanna, respectively (P < 0.0001). A histogram distribution of tHcy in the coastal groups showed a distinct group, C2 (15% of the total group), with tHcy > 28 micro mol/L. Folate < 6.75 nmol/L (lower quartile) and MTHFRCT/TT genotype were the 2 main risk factors for moderate hyperhomocysteinemia in the whole population [odds ratios: 5.3 (95% CI: 2.5, 11.2; P < 0.0001) and 4.9 (1.6, 14.8; P = 0.0048), respectively] and in the C2 group [odds ratios: 15.9 (4.5, 56.8; P < 0.0001) and 9.0 (2.3, -35.2; P = 0.0017), respectively]. Cystatin C was another potent risk factor in the C2 group.


CONCLUSIONS
A high prevalence of hyperhomocysteinemia in coastal West Africa, related to folate concentrations and the MTHFR 677 T allele, suggests the need to evaluate the influence of hyperhomocysteinemia on disease in this area.
Amouzou
Emile K
EK
Laboratory of Cellular and Molecular Pathology in Nutrition, EMI INSERM 00-14, Vandoeuvre-les-Nancy, France.
Chabi
Nicodème W
NW
Adjalla
Charles E
CE
Rodriguez-Guéant
Rosa M
RM
Feillet
François
F
Villaume
Christian
C
Sanni
Ambaliou
A
Guéant
Jean-Louis
JL
D000328:Adult; D001541:Benin / Q000453:epidemiology; D055316:Cystatin C; D015891:Cystatins / Q000097:blood; D005260:Female; D005494:Folic Acid Deficiency / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D005838:Genotype; D006801:Humans; D020138:Hyperhomocysteinemia / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D012307:Risk Factors; D014037:Togo / Q000453:epidemiology; D014805:Vitamin B 12 / Q000097:blood
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12