Comparison 2. Antioxidants versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Overall cognitive functioning	5		Mean Difference (Random, 95% CI)	Subtotals only
1.1 3‐12 months Vitamin E supplementation	1		Mean Difference (Random, 95% CI)	1.4 [1.18, 1.62]
1.2 3‐12 months Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	‐0.14 [‐0.37, 0.09]
1.3 > 2‐5 years antioxidants (Vitamin E + Vitamin C + Beta Carotene) supplementation	1		Mean Difference (Random, 95% CI)	0.09 [‐0.05, 0.23]
1.4 > 2‐5 years Vitamin E supplementation	1		Mean Difference (Random, 95% CI)	0.01 [‐0.23, 0.25]
1.5 > 2‐5 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	0.16 [‐0.08, 0.40]
1.6 > 2‐5 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	‐0.18 [‐0.42, 0.06]
1.7 > 5‐10 years antioxidants (Vitamin E + Vitamin C + Beta carotene) supplementation	1		Mean Difference (Random, 95% CI)	0.6 [‐0.20, 1.40]
1.8 > 5‐10 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	0.46 [0.14, 0.78]
1.9 > 5‐10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	‐0.13 [‐0.46, 0.20]
1.10 > 10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.18 [0.01, 0.35]
2 Episodic memory	4		Mean Difference (Random, 95% CI)	Subtotals only
2.1 3‐12 months Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.02 [‐0.05, 0.08]
2.2 > 2‐5 years Vitamin E supplementation	1		Mean Difference (Random, 95% CI)	‐0.02 [‐0.07, 0.03]
2.3 > 2‐5 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	‐0.05 [‐0.10, ‐0.00]
2.4 > 2‐5 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.01 [‐0.05, 0.07]
2.5 > 5‐10 years antioxidants (Vitamin E + Vitamin C + Beta Carotene) supplementation	1		Mean Difference (Random, 95% CI)	‐0.3 [‐1.30, 0.70]
2.6 > 5‐10 years Vitamin E supplementation	2		Mean Difference (Random, 95% CI)	0.02 [‐0.05, 0.09]
2.7 > 5‐10 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	‐0.14 [‐0.22, ‐0.06]
2.8 > 5‐10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.02 [‐0.05, 0.09]
2.9 > 10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	‐0.06 [‐0.11, ‐0.02]
3 Executive function	4		Mean Difference (Random, 95% CI)	Subtotals only
3.1 3‐12 months Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.07 [‐0.48, 0.62]
3.2 > 2‐5 years Vitamin E supplementation	1		Mean Difference (Random, 95% CI)	0.42 [0.06, 0.78]
3.3 > 2‐5 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	‐0.03 [‐0.39, 0.33]
3.4 > 2‐5 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.22 [‐0.14, 0.58]
3.5 > 5‐10 years antioxidants (Vitamin E + Vitamin C + Beta Carotene) supplementation	1		Mean Difference (Random, 95% CI)	‐0.4 [‐0.99, 0.19]
3.6 > 5‐10 years Vitamin E supplementation	2		Mean Difference (Random, 95% CI)	0.11 [‐0.26, 0.48]
3.7 > 5‐10 years Vitamin C supplementation	1		Mean Difference (Random, 95% CI)	‐0.25 [‐0.70, 0.20]
3.8 > 5‐10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.01 [‐0.44, 0.46]
3.9 > 10 years Beta Carotene supplementation	1		Mean Difference (Random, 95% CI)	0.01 [‐0.36, 0.38]
4 Incidence of dementia	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
4.1 > 2‐5 years of supplementation	1	20536	Risk Ratio (M‐H, Random, 95% CI)	1.00 [0.61, 1.64]
5 All‐cause mortality	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
5.1 > 2‐5 years antioxidants (Vitamin E + Vitamin C + + Beta Carotene) supplementation	1	20536	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.97, 1.11]