Hypocholesterolemia: a major risk factor for developing pulmonary tuberculosis?

Although one-third of the world's population is infected by Mycobacterium tuberculosis, only approximately 10% will develop the overt clinical disease due to a yet undefined risk factor. We hypothesize that hypocholesterolemia might constitute such a factor, because: (a) cholesterol is an important molecule for the good functioning of an immune system, and is necessary for macrophages to uptake and engulf mycobacteria, (b) tuberculous patients often have hypocholesterolemia, in comparison with the general population and household contacts, (c) cholesterol has a beneficial effect against pulmonary tuberculosis, since a cholesterol-rich diet accelerates the bacteriological sterilization of sputum, and (d) many conditions traditionally considered major risk factors for tuberculosis are accompanied by hypocholesterolemia. If this hypothesis proves to be true, cholesterol might be given to hypocholesterolemic subjects who are at high risk for developing pulmonary tuberculosis.