human Humans 64 female 57 male 56 Article 54 adult 49 Female 38 controlled study 38 Male 34 vitamin D 33 major clinical study 29 middle aged 22 Adult 21 Vitamin D 21 aged 20 vitamin 20 child 17 Middle Aged 16 cross-sectional study 15 metabolism 14 Aged 13 blood 13 vitamin D deficiency 13 vitamin blood level 13 Dietary Supplements 12 alpha tocopherol 12 clinical article 12 dietary supplement 12 Child 11 Cross-Sectional Studies 11