Table 2.

Comparison of observed outcomes in human studies linking vitamin D status to cognitive measures, according to potential confounding factors: gender, age and presence of pathology

Potential confounder		ASSOCIATIVE STUDIES			INTERVENTIONAL STUDIES
		Number of studies	Results		Number of studies	Results
			Association (Number of studies)	No association (Number of studies)		Improvement (Number of studies)	No improvement (Number of studies)
GENDER	Women	5	5	0	1	0	1
		[93–97]	[93–97]		[98]		[98]
	Men	1	0	1	0	0	0
		[99]		[99]
	Both	15	12	4	8	2	6
		[100–114]	[100–109, 111]	[110, 112–114]	[115–121]	[116, 119]	[115, 117, 118, 120, 121]
AGE	Under 65	5	1	4	1	0	1
		[109, 110, 112–114]	[109]	[110, 112–114]	[118]		[118]
	Over 65	13	12	1	8	2	6
		[93–97, 99, 101–103, 105–108]	[93–97, 101–103, 105–108]	[99]	[98, 115–117, 119–121]	[115, 119]	[98, 116, 117, 120, 121]
PATHOLOGY	Cognitively healthy elderly	13	9	4	5	2	3
		[95–97, 99, 102–104, 106–108, 110, 111, 114]	[95–97, 102, 103, 106–108, 111]	[99, 104, 110, 114]	[98, 115, 117, 119, 120]	[115, 119]	[98, 117, 120]
	MCI, AD, non-AD dementia	5	5	0	3	0	3
		[93, 94, 100, 101, 105]	[93, 94, 100, 101, 105]		[116, 121]		[116, 121]