Previously we reported on collaborators who were working with us to measure vitamin D in blood samples collected from Health 2020 participants when they joined the study. This work is the subject of Alicia Heath’s recently completed PhD thesis.
Vitamin D is an important topic, as many Australians are found to have low levels. It is well known that vitamin D is needed for strong healthy bones but research also suggests an association between low levels of vitamin D and an increased risk of a range of other health problems.
Vitamin D exists as two main forms which can be measured in our blood: D3 (produced on exposure to sunlight) and D2 (produced by fungi and yeasts and used in some dietary supplements and food additives, mainly in the USA).
Alicia found that higher levels of total vitamin D or D3, which was most of the vitamin D in Health 2020 participants, were associated with a lower risk of death; specifically deaths due to cancer, respiratory or digestive diseases and a lower risk of developing diabetes. For the participants for whom any vitamin D2 was detected, the risk of death was higher than for those for whom none was detected. These results suggest that vitamin D3 might be helpful in preventing type 2 diabetes and premature death, whereas vitamin D2 might have an adverse effect on health.
Future observational studies should distinguish between these two forms of vitamin D to explore whether they are differently associated with health outcomes other than bone health.