Researchers have found that free and circulating vitamin D levels in the blood may be a better predictor of future health risks in ageing men.
Vitamin D deficiency is associated with a higher risk for developing many ageing-related diseases, such as cardiovascular disease, cancer and osteoporosis, according to the study, presented at e-ECE 2020 online conference on Tuesday.
There are several forms, or metabolites, of vitamin D in the body but it is the total amount of these metabolites that are most often used to assess the vitamin D status of people, the researchers said.
The prohormone, 25-dihydroxy vitamin D is converted to 1,25-dihydroxy vitamin D, which is considered the active form of vitamin D in our body. More than 99 per cent of all vitamin D metabolites in our blood are bound to proteins, so only a very small fraction is free to be biologically active. Therefore the free, active forms may be a better predictor of current and future health.
For the findings, the research team from University Hospitals Leuven in Belgium investigated whether the free metabolites of vitamin D were better health predictors, using data from the European Male Ageing Study, which was collected from 1,970 men, aged 40-79.
The levels of total and free metabolites of vitamin D were compared with their current health status, adjusting for potentially confounding factors, including age, body mass index, smoking and self-reported health.The total levels of both free and bound vitamin D metabolites were associated with a higher risk of death. However, only free 25-hydroxyvitamin D was predictive of future health problems and not free 1,25-dihydroxy vitamin D.
"These data further confirm that vitamin D deficiency is associated with a negative impact on general health and can be predictive of a higher risk of death," said study author Leen Antonio from University Hospitals Leuven."Most studies focus on the association between total 25-hydroxyvitamin D levels and age-related disease and mortality," Antonio added.
According to the team, as 1,25-dihydroxy vitamin D is the active form of vitamin D in our body, it was possible it could have been a stronger predictor for disease and mortality. It has also been debated if the total or free vitamin D levels should be measured."Our data now suggest that both total and free 25-hydroxyvitamin D levels are the better measures of future health risk in men," said Antonio.