Rheumatoid arthritis (RA) causes premature mortality, disability and compromised quality of life in the industrialized and developing world (1). Rheumatoid arthritis is a systemic inflammatory disease which manifests itself in multiple joints of the body.
A baritone is the most common type of male voice whose range lies midway between the high tenor voice and the low bass voice. In comedic operas, he is often the leader of the funny business, but he can also be the hero, who sacrifices himself for the tenor or soprano, or the villain.
In short: the bass-baritone is a voice that has the resonant low notes of the typical bass allied with the ability to sing in a baritonal tessitura. Colloquially, it refers to a voice with a range and tone somewhere between a bass and a baritone.