middle aged human 174 Humans 166 Middle Aged 164 male 162 adult 160 Male 154 female 152 Female 144 Adult 126 article 96 controlled study 84 aged 74 Article 70 Aged 66 priority journal 64 major clinical study 48 adolescent 44 Adolescent 42 Argentina 42 genetics 38 metabolism 38 clinical article 36 physiology 36 child 32 Young Adult 30 pathology 30 Child 28 young adult 28 Animals 22