title: Seasonal changes in human plasma levels of 25-hydroxyvitamin D.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D004032:Diet; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D008297:Male; D012621:Seasons; D012737:Sex Factors; D013472:Sunlight; D014807:Vitamin D
chemical_list: D006887:Hydroxycholecalciferols; D014807:Vitamin D