Thanks Albert, that's the full text to the abstract I linked. Of course smoking's direct irritant effects have been known for years. The more insidious aspects of alcohol—interference with cilia would make normal coughing ineffective as a defense—seems to have been noticed more recently.
Mixed reports about Bix's smoking. 20 a day according to Keeley's intake. Sudhalter/Evans describe him as chain-smoking, at least while trying not to drink.