Ok, got it. I've always thought the bronchiectasis came first and then the NTM. Maybe exposure to NTM causes bronchiectasis? Also, as we age our immune function declines making us more susceptible but then again more people would have bronchiectasis.

Not really an answer but there's a recent paper by Dr. McShane and other bronchiectasis experts, "The Impact of Tobacco Smoking in Bronchiectasis: Data from the U.S. Bronchiectasis and Nontuberculous Mycobacteria Research Registry" which might shed more light on bronchiectasis. The registry indicates that half of all people with bronchiectasis smoked. It's behind an access wall but you can read the first page here. https://www.atsjournals.org/doi/full/10.1164/rccm.202402-0466RL?role=tab