Although in many studies pesticides were investigated in general, it was shown that COPD and airway obstruction were associated especially with occupational exposure to acetylcholine esterase-inhibiting insecticides (organophosphates and carbamates), and in some studies also with organochlorine pesticides and some herbicides (especially paraquat) [9,22,23,24,25]. This evidence concerns the gene ACHE and Airway obstruction.