Last month, October of 2011, a Spanish group documented what the Vitamin D Council first reported several years ago: vitamin D levels in indoor athletes are likely to be very low.
Bescós García R, Rodríguez Guisado FA. Low levels of vitamin D in professional basketball players after wintertime: relationship with dietary intake of vitamin D and calcium. Nutr Hosp. 2011 Oct;26(5):945-51.