What do systematic reviews say?

Vitamin D given to infants vs vitamin D given to lactating mothers

Vitamin D given to infants showed no clear difference in adverse effect (hypercalcaemia) compared with vitamin D given to lactating mothers (low certainty).

• Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health 2020 · Cochrane Headline outcomes only
  RR 1.22 [0.48, 3.09]
  1 study · 97 participants
  Low

Vitamin D plus calcium vs placebo or control

Vitamin D [D2, D3 or 25(OH)D] plus calcium showed no clear difference in persons with hypercalcaemia ‐ Vitamin D (D2, D3 or 25(OH)D) plus… compared with control or placebo (low certainty).

• Vitamin D and vitamin D analogues for preventing fractures in post‐menopausal women and older men 2014 · Cochrane Headline outcomes only
  RR 3.29 [0.37, 29.14]
  2 studies · 3853 participants
  Low

Vitamin D plus calcium vs placebo or control

Vitamin D [D2, D3 or 25(OH)D] plus calcium leads to higher persons with renal disease (calculi or insufficiency) ‐ Vitamin D… compared with control or placebo (high certainty).

• Vitamin D and vitamin D analogues for preventing fractures in post‐menopausal women and older men 2014 · Cochrane Headline outcomes only
  RR 1.17 [1.03, 1.34]
  2 studies · 39552 participants
  High

Vitamin D plus calcium vs placebo or control

Vitamin D [D2, D3 or 25(OH)D] plus calcium showed no clear difference in deaths ‐ Vitamin D (D2, D3, 25(OH)D) plus calcium (1 year estimate) compared with control or placebo (high certainty).

• Vitamin D and vitamin D analogues for preventing fractures in post‐menopausal women and older men 2014 · Cochrane Headline outcomes only
  RR 0.94 [0.87, 1.02]
  6 studies · 46794 participants
  High

Vitamin D vs placebo

• Vitamin D as an adjunct to antibiotics for the treatment of acute childhood pneumonia 2023 · Cochrane Headline outcomes only
  no estimate extracted
  5 studies · 1188 participants
  Moderate

Vitamin D vs placebo

• Vitamin D as an adjunct to antibiotics for the treatment of acute childhood pneumonia 2023 · Cochrane Headline outcomes only
  no estimate extracted
  5 studies · 1023 participants
  Very low

Vitamin D vs placebo

Vitamin D showed no clear difference in mortality rate ( compared with placebo (low certainty).

• Vitamin D as an adjunct to antibiotics for the treatment of acute childhood pneumonia 2023 · Cochrane Headline outcomes only
  RR 0.69 [0.44, 1.07]
  3 studies · 584 participants
  Low

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo

Vitamin D showed no clear difference in withdrawals from the study for any reason compared with placebo (moderate certainty).

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  RR 0.74 [0.46, 1.19]
  2 studies · 189 participants
  Moderate

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo

The review found no eligible studies for this question.

• Calcium and vitamin D for increasing bone mineral density in premenopausal women 2023 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo or no intervention

It is very uncertain whether vitamin D changes all‐cause mortality compared with placebo or no intervention (very low certainty).

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  RR 0.86 [0.51, 1.45]
  27 studies · 1979 participants
  Very low

Vitamin D vs placebo or no intervention

It is very uncertain whether vitamin D changes liver‐related mortality compared with placebo or no intervention (very low certainty).

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  RR 1.62 [0.08, 34.66]
  1 study · 18 participants
  Very low

Vitamin D vs placebo or no intervention

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  Very low

Vitamin D vs placebo or no intervention

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Vitamin D vs placebo or no intervention

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Vitamin D vs placebo or no intervention

• Vitamin D supplementation for chronic liver diseases in adults 2021 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  Very low