One group of people that asbestos exposure has hit considerably hard is sheet metal workers. As many people know, exposure to asbestos has been linked to several diseases including mesothelioma, lung cancer, and asbestosis. We must remain vigilant when it comes to supporting research so we can someday find a cure or at least mitigate the damage to some extent. One study that addresses the issue is called, “Asbestos-induced pleural fibrosis and impaired lung function.” By Schwartz DA, Fuortes LJ, Galvin JR, Burmeister LF, Schmidt LE, Leistikow BN, LaMarte FP, and Merchant JA -
Am Rev Respir Dis. 1990 Feb;141(2):321-6 - Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242. Here is an excerpt:

“To assess the clinical significance of asbestos-induced pleural fibrosis, we evaluated the relationship between radiographic evidence of pleural fibrosis and spirometric values in 1,211 sheet metal workers. Of those with pleural fibrosis (n = 334), 78% had circumscribed plaques and 22% had diffuse pleural thickening involving the costophrenic angle. Factors that were found to be associated with the presence and type of pleural fibrosis included increased age (p less than 0.001), more years in the trade (p less than 0.0001), more years since first exposure to asbestos (p less than 0.0001), more pack-years of cigarette smoking (p less than 0.01), and the presence and degree of interstitial fibrosis (p less than 0.0001). After controlling for these potential confounders (age, years in the trade, latency, pack-years of smoking, and ILO profusion category), linear multivariate regression models demonstrated that both circumscribed plaques (p = 0.007) and diffuse pleural thickening (p = 0.008) were independently associated with decrements in FVC but not with decrements in the FEV1/FVC ratio. Furthermore, our data indicate that the effect of diffuse pleural thickening on decrements in FVC is approximately twice as great as that seen with circumscribed pleural plaques. We conclude that the presence and type of pleural fibrosis among asbestos-exposed workers is independently associated with a pattern of spirometry that is suggestive of an underlying restrictive defect in lung function.”

This isn't the only study that looks at the impact of smoking cigarettes in connection with asbestos related diseases. Another interesting study on point is called, “Asbestos and Smoking” by Irving J. Selikoff, MD and E. Cuyler Hammond, ScD - JAMA. 1979;242(5):458-459. Here is an excerpt: “More than ten years ago, THE JOURNAL published information that some cancer deaths associated with prior asbestos exposure might be related to more than asbestos alone and could be multifactorial in origin.1 It had been found that inhalation of the mineral fibers greatly increased the already high lung cancer risk for cigarette smokers. In the group studied, it was calculated that asbestos workers who smoked cigarettes had roughly 90 times the risk for similar men who neither smoked nor worked with asbestos. In the decade since, this has been amply confirmed,2 and the observations made provide much clinical guidance in the care and surveillance of those who have been exposed in the past and who are now in the future at risk of asbestos-associated disease.”

If you found either of these studies interesting, you should read them in their entirety.

Monty Wrobleski is the author of this article on Mesothelioma Lawsuit Settlements, Asbestos Lawsuit Settlement