“…Nevertheless, there is strong evidence indicating an elevated prevalence of VDD among older age subjects [ 27 , 28 ], persons with darker skin pigmentation [ 44 ], obesity, and metabolic syndrome [ 27 , 45 ]. High VDD was demonstrated in patients with metabolic bone disorders [ 46 ], autoimmune diseases [ 47 , 48 , 49 ], including rheumatic disorders [ 50 , 51 , 52 , 53 ], inflammatory bowel diseases [ 54 , 55 ], infectious diseases [ 56 , 57 ], endocrine system disorders (type I diabetes mellitus, thyroid diseases, etc.) [ 58 , 59 , 60 ], cardiovascular [ 61 , 62 , 63 ], nervous system disorders [ 64 , 65 , 66 ], kidney diseases [ 67 ], chronic obstructive pulmonary disease [ 68 ], and tumors [ 69 ].…”