title: Homocysteine levels and dementia risk in Yoruba and African Americans.
abstract: BACKGROUND
  High levels of homocysteine have been associated with increased risk for dementia although results have been inconsistent. There are no reported studies from the developing world including Africa.
  
  
  METHODS
  In this longitudinal study of two community-dwelling cohorts of elderly Yoruba and African Americans, levels of homocysteine, vitamin B12 and folate were measured from blood samples taken in 2001. These levels were compared in two groups, participants who developed incident dementia in the follow-up until 2009 (59 Yoruba and 101 African Americans) and participants who were diagnosed as cognitively normal or in the good performance category at their last follow-up (760 Yoruba and 811 African Americans). Homocysteine levels were divided into quartiles for each site.
  
  
  RESULTS
  After adjusting for age, education, possession of ApoE, smoking, and time of enrollment the higher quartiles of homocysteine were associated with a non-significant increase in dementia risk in the Yoruba (homocysteine quartile 4 vs. 1 OR: 2.19, 95% CI 0.95-5.07, p = 0.066). For the African Americans, there was a similar but non-significant relationship between higher homocysteine levels and dementia risk. There were no significant relationships between levels of vitamin B12 and folate and incident dementia in either site although folate levels were lower and vitamin B12 levers were higher in the Yoruba than in the African Americans.
  
  
  CONCLUSIONS
  Increased homocysteine levels were associated with a similar but non-significant increase in dementia risk for both Yoruba and African Americans despite significant differences in folate levels between the two sites.
authors.affiliation: Indiana University Center for Aging Research, Indianapolis, Indiana, USA.
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hendrie
authors.forename: Olusegun
authors.initials: O
authors.lastname: Baiyewu
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Lane
authors.forename: Christianna
authors.initials: C
authors.lastname: Purnell
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
authors.forename: Ann
authors.initials: A
authors.lastname: Hake
authors.forename: Adesola
authors.initials: A
authors.lastname: Ogunniyi
authors.forename: Oye
authors.initials: O
authors.lastname: Gureje
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Unverzagt
authors.forename: Jill
authors.initials: J
authors.lastname: Murrell
authors.forename: Mark A
authors.initials: MA
authors.lastname: Deeg
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hall
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D044383:Black People / Q000706:statistics & numerical data*; D003704:Dementia / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D015994:Incidence; D007196:Indiana / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D009549:Nigeria / Q000453:epidemiology; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12
references.citation: Alzheimers Dement. 2011 Jul;7(4):412-7
references.pmid: 21784352
references.citation: Ethn Dis. 2008 Autumn;18(4):427-33
references.pmid: 19157246
references.citation: Public Health Nutr. 2014 Feb;17(2):455-61
references.pmid: 23211101
references.citation: Int Psychogeriatr. 2006 Dec;18(4):653-66
references.pmid: 16640794
references.citation: Lancet Neurol. 2011 Sep;10(9):819-28
references.pmid: 21775213
references.citation: Alzheimer Dis Assoc Disord. 2011 Jan-Mar;25(1):4-10
references.pmid: 20921881
references.citation: Am J Clin Nutr. 2007 Feb;85(2):511-7
references.pmid: 17284751
references.citation: Int J Geriatr Psychiatry. 2000 Jun;15(6):521-31
references.pmid: 10861918
references.citation: Neurology. 2001 Nov 13;57(9):1655-62
references.pmid: 11706107
references.citation: J Am Geriatr Soc. 2008 Jan;56(1):51-8
references.pmid: 18028343
references.citation: Can J Psychiatry. 2004 Feb;49(2):92-9
references.pmid: 15065742
references.citation: Am J Clin Nutr. 2006 Mar;83(3):708-13
references.pmid: 16522921
references.citation: J Neurol Neurosurg Psychiatry. 2008 Aug;79(8):864-8
references.pmid: 18252751
references.citation: Eur J Neurol. 2009 Jul;16(7):808-13
references.pmid: 19453410
references.citation: Cell Biochem Funct. 2009 Dec;27(8):568-77
references.pmid: 19764044
references.citation: J Am Geriatr Soc. 1988 May;36(5):402-8
references.pmid: 3361042
references.citation: JAMA. 2001 Feb 14;285(6):739-47
references.pmid: 11176911
references.citation: Neurology. 2004 Jun 8;62(11):1972-6
references.pmid: 15184599
references.citation: Br J Nutr. 2010 Sep;104(6):893-9
references.pmid: 20398433
references.citation: Neurology. 1989 Sep;39(9):1159-65
references.pmid: 2771064
references.citation: J Alzheimers Dis. 2010;22(1):205-24
references.pmid: 20847412
references.citation: JAMA. 2003 Aug 20;290(7):932-40
references.pmid: 12928471
references.citation: N Engl J Med. 2002 Feb 14;346(7):476-83
references.pmid: 11844848
references.citation: Eur J Neurol. 2002 Nov;9(6):573-80
references.pmid: 12453071
references.citation: Ann Intern Med. 2010 Aug 3;153(3):182-93
references.pmid: 20547887
references.citation: Neurology. 1984 Jul;34(7):939-44
references.pmid: 6610841
references.citation: Lancet. 2005 Dec 17;366(9503):2112-7
references.pmid: 16360788
references.citation: Am J Geriatr Psychiatry. 2011 Jul;19(7):607-17
references.pmid: 21705865