Table 1.

Search strategy used in the PubMed database search

	(“Vitamin B Complex”[Mesh] OR “Thiamine”[Mesh] OR “Vitamin B6”[Mesh] OR “Folic Acid”[Mesh] OR “Vitamin B12”[Mesh] OR “Vitamin B”[Title/Abstract] OR “Thiamine”[Title/Abstract] OR “Vitamin B1”[Title/Abstract] OR “Pyridoxine”[Title/Abstract] OR “Vitamin B6”[Title/Abstract] OR “Folic Acid”[Title/Abstract] OR “Folate”[Title/Abstract] OR “Vitamin B9”[Title/Abstract] OR “Cobalamine”[Title/Abstract] OR “Vitamin B12”[Title/Abstract] OR “Homocysteine”[Title/Abstract] OR “Hyperhomocysteinemia”[Title/Abstract])
AND	(“Humans”[Mesh])
AND	(“Cohort”[Title/Abstract] OR “Follow-Up”[Title/Abstract] OR “Longitudinal”[Title/Abstract] OR “Prospective”[Title/Abstract] OR “Retrospective”[Title/Abstract] OR "Study"[Title/Abstract] OR "Trial"[Title/Abstract]) AND “controlled”[Title/Abstract])
AND	(“Cognitive”[Title/Abstract] OR “Cognition”[Title/Abstract])