Researchers at the Medical college of Wisconsin have recently shown that smoking leads to damage of the protective reflexes in the throat area. A one-way valve keeps stomach acid from flowing back into the hroat and smoking causes damage to the pharyngoglottal closure reflex, which closes off the vocal chords if fluid enters the area, a condition known as reflex disease.
Ten smokers and ten non-smokers were tested by imaging the relex area before and after cigarettes. The smokers after smoking, when injected with water to simulate stomach acid, were found to have an impaired reflex triggering. The clinical consequences of such a condition and the reversal of damage by smoking cessation is yet to be studied in detail.