The majority, 160 () of the subjects had been working in their units for more than two years while 64 () had not spent up to one year in their various units. Most 254 () reported negative history of chronic cough while a higher percentage 257 () denied any history of smoking. In relation to alcohol consumption, 44 () gave history of alcohol intake, the majority 208 () gave a negative history while 19 () did not give any definite answer. Eleven () subjects agreed to recently have contact with patients with chronic cough, 178 () gave negative response while 82 () did not answer the question. Concerning previous history of tuberculin skin.
