Table 2.

Prospective study of HHcy and AD/Cognitive decline

	Study	Average age of participants	Sample size	Duration	Results
HHcy as predictor for cognitive decline/AD	McCaddon, Hudson et al. 2001 98	> 60 years	n= 32	5 years	Baseline Hcy level predict cognitive decline
	Dufouil, Alperovitch et al. 2003 99	67 years	n= 1241	4 year	Cognitive decline 2.8 fold higher in people with Hcy >15 µM
	Seshadri, Beiser et al. 20027	76.6 years	n= 1092	8 years	Plasma Hcy > 14 µM nearly double the AD risk
	Ravaglia, Forti et al. 2005 100	74 years	N= 816	4 years	HHcy associated with AD risk
	Tucker, Qiao et al. 2005 101	67 years	n= 321	3 years	Hcy level predict the cognitive decline
	Annerbo, Wahlund et al. 200621	> 60 year	n= 93 MCI patients	6 years	Hcy level predict the AD development
	Haan Miller et al. 2006 102	> 60 years	n= 1779	4.5 years	High hcy level is associated with dementia
	Annerbo, Kivipelto et al. 2009 103	> 75 years	n= 200	6.7 year	High Hcy level is related with high AD risk
	Zylberstein, Lissner et al. 201120	38–60 years	n= 1368	35 years	Baseline Hcy level in midlife can predict the AD risk in later stage
	Oulhaj, Refsum et al.22	> 50 years	n= 97 AD patients	1.5–9.5 years	Raised hcy level predict the cognitive decline in Ad patients
HHCy is not predictor of cognitive decline/AD	Kalmijn, Launer et al. 1999 101	>55 years	n= 702	2.7 years	No association between HHcy and AD
	Luchsinger, Tang et al. 2004 102	>60 years	N= 679	5 years	HHcy is not associated with memory score