Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements .
The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics .
However , for vitamin D2 supplementation , increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods .
Conclusions Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease , cancer , and other causes .
Objective To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with  mortality from cardiovascular , cancer , or other conditions  , under various circumstances .
The effects of calcitriol on falls and fractures and physical performance tests
There is an increase in the incidence of falls with aging and about 10 % of falls lead to fractures . Nearly all hip fractures are due to falls and hip fractures are the most severe of the osteoporotic fractures because they lead to a 20 % mortality rate and a loss of independent living in 50 % of cases . Although there are multiple factors associated with falls , our interest is the role that vitamin D metabolism plays in the pathogenesis of falls . Recent clinical trials show that both vitamin D and the metabolite calcitriol reduce the number of falls by 30 - 40 % in elderly subjects . This should also reduce the number of fractures . In European studies , the decrease in falls could be attributed to an improvement in the muscle weakness that often accompanies vitamin D deficiency . However , in the studies using calcitriol there was no vitamin D deficiency , so the mechanism of its efficacy is less clear . It could be due to increased muscle strength , an improvement in the neurological control of balance or both . Underst and ing these mechanisms would allow us to search for analogs of vitamin D that act more selectively on muscle and on the central nervous system
Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements .
The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics .
However , for vitamin D2 supplementation , increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods .
Conclusions Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease , cancer , and other causes .
Objective To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with  mortality from cardiovascular , cancer , or other conditions  , under various circumstances .