Summary of findings 3. Vitamin D3 compared to placebo for maintaining cognitive function in cognitively healthy people in mid and late life.

Vitamin D3 compared to placebo for maintaining cognitive function in cognitively healthy people in mid and late life
Patient or population: cognitively healthy people in mid and late life Setting: community Intervention: vitamin D3 +/‐ calcium carbonate Comparison: placebo
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Risk with placebo	Risk with Vitamin D3
Overall cognitive functioning assessed with: MoCA change from baseline Scale from: 0 to 30 follow‐up: 6 months	There was no significant difference between groups in the change in MoCA score (P=0.186).			60 (1 RCT)	⊕⊕⊕⊝ MODERATE 1	Experimental intervention was vitamin D3 4000 IU on alternate days. Data not fully reported (conference abstract only).
Overall cognitive functioning assessed with: 3MS Scale from: 0 to 100 follow‐up: mean 7.8 years	The mean 3MS score was 96.6	MD 0.1 lower (0.81 lower to 0.61 higher)	‐	918 (1 RCT)	⊕⊕⊝⊝ LOW 2 3	Experimental intervention was vitamin D3 400 IU/day and calcium carbonate 1000 mg/day.
Incidence of probable dementia or MCI follow‐up: mean 7.8 years	No significant difference in incidence between treatment groups. In an intention‐to‐treat analysis, incidence was 62.2/10 000 person‐years in the vit D + Ca group and 65.9/10 000 person‐years in the placebo group (HR 0.94, 95% CI 0.72 to 1.24, P = 0.68).		‐	4143 (1 RCT)	⊕⊕⊝⊝ LOW3 4	Experimental intervention was vitamin D3 400 IU/day and calcium carbonate 1000 mg/day.
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; OR: Odds ratio;
GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

¹ Downgraded for imprecision (small sample size)

² Downgraded for risk of bias due to incomplete outcome data

³ Downgraded for indirectness (study included women only)

⁴ Downgraded for imprecision due to wide confidence interval

^{MCI: Mild Cognitive Impairment
 MOCA: Montreal cognitive assessment
 3MS: The Modified Mini‐Mental State Examination}