REN and obesity disorder: In cluster #0, the associated keywords include “obesity” and “nutrition.” In cluster#1 “response,” the most appeared keywords are “d receptor,” “mycobacterium tuberculosis,” “experimental autoimmune encephalomyelitis” and “asthma.” In cluster #2 “zinc,” the keywords mentioned mainly include “supplementation,” and “adolescent.” In cluster#13 “COVID-19,” the most prevalent keywords are “ace2,” “severe acute respiratory syndrome coronavirus 2,” “renin-angiotensin-aldosterone system” and “sars-cov-2.”