The vast majority of studies reported inverse associations between 25(OH)D concentration and all-cause mortality .
This association appeared to be non-linear , with progressively lower mortality with increasing 25(OH)D up to a point , beyond which there was no further decrease .
There is moderate evidence that vitamin D status is inversely associated with cancer mortality and death due to respiratory diseases , while for cardiovascular mortality , there is weak evidence of an association in observational studies , which is not supported by the data from intervention or Mendelian r and omization studies .
Epidemiological evidence suggests that vitamin D deficiency is associated with increased mortality , but it is unclear whether this is explained by reverse causation , and if there are specific causes of death for which vitamin D might be important .
The D-Health Trial: A randomized trial of vitamin D for prevention of mortality and cancer.
BACKGROUND Vitamin D , specifically serum 25(OH)D has been associated with mortality , cancer and multiple other health endpoints in observational studies , but there is a paucity of clinical trial evidence sufficient to determine the safety and effectiveness of population -wide supplementation . We have therefore launched the D-Health Trial , a r and omized trial of vitamin D supplementation for prevention of mortality and cancer . Here we report the methods and describe the trial cohort . METHODS The D-Health Trial is a r and omized placebo-controlled trial , with planned intervention for 5years and a further 5years of passive follow-up through linkage with health and death registers . Participants aged 65 - 84years were recruited from the general population of Australia . The intervention is monthly oral doses of 60,000IU of cholecalciferol or matching placebo . The primary outcome is all-cause mortality . Secondary outcomes are total cancer incidence and colorectal cancer incidence . RESULTS We recruited 21,315 participants to the trial between February 2014 and May 2015 . The participants in the two arms of the trial were well-balanced at baseline . Comparison with Australian population statistics shows that the trial participants were less likely to report being in fair or poor health , to be current smokers or to have diabetes than the Australian population . However , the proportion overweight or with health conditions such as arthritis and angina was similar . CONCLUSIONS Observational data can not be considered sufficient to support interventions delivered at a population level . Large-scale r and omized trials such as the D-Health Trial are needed to inform public health policy and practice
The vast majority of studies reported inverse associations between 25(OH)D concentration and all-cause mortality .
This association appeared to be non-linear , with progressively lower mortality with increasing 25(OH)D up to a point , beyond which there was no further decrease .
There is moderate evidence that vitamin D status is inversely associated with cancer mortality and death due to respiratory diseases , while for cardiovascular mortality , there is weak evidence of an association in observational studies , which is not supported by the data from intervention or Mendelian r and omization studies .
Epidemiological evidence suggests that vitamin D deficiency is associated with increased mortality , but it is unclear whether this is explained by reverse causation , and if there are specific causes of death for which vitamin D might be important .