IGHE and obesity due to melanocortin 4 receptor deficiency: Total IgE levels have been independently associated, in non-atopic individuals, with cigarette smoking and alcohol consumption, while variable concentrations have also been detected in aging, autoimmunity, immunodeficiency (e.g., Job’s Syndrome), cancer, obesity, parasitic infection, and metabolic syndrome [30]; otherwise, allergic patients may have low total IgE levels.