Comparison 3. Vitamin D3 versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Overall cognitive functioning	1		Mean Difference (Random, 95% CI)	Subtotals only
1.1 3‐12 months of supplementation	1	4122	Mean Difference (Random, 95% CI)	0.0 [‐0.24, 0.24]
1.2 > 1‐2 years of supplementation	1	3910	Mean Difference (Random, 95% CI)	0.0 [‐0.25, 0.25]
1.3 > 2‐5 years of supplementation	1	3515	Mean Difference (Random, 95% CI)	‐0.2 [‐0.53, 0.13]
1.4 > 5‐10 years of supplementation	1	918	Mean Difference (Random, 95% CI)	‐0.1 [‐0.81, 0.61]
2 Episodic memory	1		Mean Difference (Random, 95% CI)	Subtotals only
2.1 > 5‐10 years of supplementation	1	1420	Mean Difference (Random, 95% CI)	0.05 [‐0.03, 0.13]
3 Executive function	1		Mean Difference (Random, 95% CI)	Subtotals only
3.1 > 5‐10 years of supplementation	1	1420	Mean Difference (Random, 95% CI)	0.0 [‐0.08, 0.08]
4 Speed of processing	1		Mean Difference (Random, 95% CI)	Subtotals only
4.1 > 5‐10 years of supplementation	1	1420	Mean Difference (Random, 95% CI)	0.03 [‐0.05, 0.11]
5 Incident MCI	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
5.1 > 5‐10 years of supplementation	1	4143	Risk Ratio (M‐H, Random, 95% CI)	0.94 [0.72, 1.23]
6 Incident all‐cause dementia	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
6.1 > 5‐10 years supplementation	1	4143	Risk Ratio (M‐H, Random, 95% CI)	1.09 [0.70, 1.71]