The cities of Libby and Dillon, Montana export vermiculite orethat is used in several products such as attic insulation, lawn andgarden materials, and fireproofing materials. A study was conductedwith 4000 workers who either worked In the ore mine or theproduction facilities of either the Libby mine (n=2900) or theDillon mine (n=1100) to determine if working with the mined ore wasassociated with lung cancer. The workers were followed from 1985 to1990 when the Libby mine was closed after asbestos was found in theore. Of the 2900 workers who were exposed to asbestos on the Libbymine, 100 people were diagnosed with lung cancer during the fiveyear follow up period. During the same time period, 10 people werediagnosed with lung cancer from the Dillon mine. Consider that theproportion of the total population that is exposed to asbestos is25%.
a) What type of study design is this ?
b) Construct a 2X2 table for this study which showsDisease+, Disease-, Exposure +, and Exposure -.
c) What is the incidence of lung cancer among thoseexposed to asbestos?
d) What is the incidence of lung cancer among thosenot exposed to asbestos?
