Bariatric Surgery / Minerals / Folic acid / Adolescent / Humans / Female / Male / Young Adult / Iron / Income / Body Mass Index / Parathyroid Hormone / Obesity Surgery / Clinical Sciences / Aged / Prevalence / Middle Aged / Adult / Public health systems and services research / Sex Factors / Morbid Obesity / Educational Status / Iron Deficiency Anemia / Hemoglobins / Preoperative Period / Avitaminosis / Female / Male / Young Adult / Iron / Income / Body Mass Index / Parathyroid Hormone / Obesity Surgery / Clinical Sciences / Aged / Prevalence / Middle Aged / Adult / Public health systems and services research / Sex Factors / Morbid Obesity / Educational Status / Iron Deficiency Anemia / Hemoglobins / Preoperative Period / Avitaminosis