Diet, sunlight, and 25-hydroxy vitamin D.
D000368:Aged; D004032:Diet; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D013472:Sunlight; D014467:Ultraviolet Therapy; D014807:Vitamin D / Q000378:metabolism / Q000627:therapeutic use*
D006887:Hydroxycholecalciferols; D014807:Vitamin D