Although the relation between sleep and vitamin D levels is still controversial, many mechanisms may be implied: for example, TNF-alpha has a role in the pathogenesis of sleep apnea syndrome and is negatively correlated with vitamin D,[39] and the need for sleep during daytime may decrease exposure to sunlight.[40] On the other hand, the relationship between Vitamin D and MPV found in the present study is in line with results shown by Cumhur Cure in 2014 [41] that showed that low vitamin D is independently associated with a high MPV. The gene discussed is TNF; the disease is sleep apnea syndrome.