Blood transfusion – doner should have similar vitamin D level
Otherwise your body has to somehow increase the vitamin D in the donated blood
Typically low level
African-American
Obese
People with many health problems
Might be advisable to supplement with vitamin D if the donated blood has a low vitamin D level
Perhaps future blood will not only be checked for type but also vitamin D level
Do not expect this to happen until vitamin D test time and costs are both significantly reduced
Observation by VitaminDWiki April 2015