Another winter storm, Remus, is traversing the US. More than 175 million people from the Upper Midwest to the interior South and Northwest will have to endure severe cold conditions. Without doubt, people living in these regions will not be exposing much skin for vitamin D synthesis in the skin.
Cold weather is one of the environmental factors contributing to low vitamin D status. Genetics is another factor. Hansen and colleagues report that 55% of African Americans studied in the Health ABC Study were vitamin D insufficient