European scientists have reported a huge study contributing to vitamin D effect on patient mortality in the elderly age.
It is presumed that vitamin D may affect multiple health outcomes.
If so, an effect on mortality is to be expected.
Using pooled data from randomized controlled trials, the scientists performed individual patient data (IPD) and trial level meta-analyses to assess mortality among participants randomized to either vitamin D alone or vitamin D with calcium.
The subjects and methods of investigation was performed in a way that in the beginning through a systematic literature search, they identified 24 randomized controlled trials reporting data on mortality in which vitamin D was given either alone or with calcium.
From a total of 13 trials with more than 1000 participants each, eight trials were included in their IPD analysis.
Using a stratified Cox regression model, the scientists calculated risk of death during 3 years of treatment in an intention-to-treat analysis.
Also, they performed a trial level meta-analysis including data from all studies.
The IPD analysis of this study yielded data on 70,528 randomized participants (86.8% females) with a median age of 70 (interquartile range, 62-77) years.
Vitamin D with or without calcium reduced mortality by 7% [hazard ratio, 0.93; 95% confidence interval (CI), 0.88-0.99].
However, vitamin D alone did not affect mortality, but risk of death was reduced if vitamin D was given with calcium (hazard ratio, 0.91; 95% CI, 0.84-0.98).
The number needed to treat with vitamin D plus calcium for 3 years to prevent one death was 151.
Trial level meta-analysis (24 trials with 88,097 participants) showed similar results, i.e. mortality was reduced with vitamin D plus calcium (odds ratio, 0.94; 95% CI, 0.88-0.99), but not with vitamin D alone (odds ratio, 0.98; 95% CI, 0.91-1.06).
To conclude it can be stated that vitamin D with calcium reduces mortality in the elderly, whereas available data do not support an effect of vitamin D alone.