Background: Indoor air pollution released by the combustion of smoky coal in recycled unaired results in elevated lung cancer
mortality. Methodology: This is a case-control study that investigated 300 Saudi civilians who were selected from Hail city. Household
smoke-exposed (Shabbah) individuals (N=250) were ascertained as cases and non-exposed (N=50) were ascertained as controls.
Sputum specimen was obtained from each participant and assessed cytologically. Results: Metaplasia was identified in
38/250(15.2%) of the cases and 5/50(10%) of the controls. The risk of lung epithelium metaplasia associated with exposure to
Shabbah smoke, the odds ratio (OR), and 95% confidence interval (95%CI) was 1.6132 (0.6016 to 4.3257), P = 0.3420, z statistic =
0.950. Acute inflammatory cell infiltration was identified in 30/250(12%) of the cases and 9/50(18%) of the controls. Chronic
inflammatory cell infiltration was identified in 51/250(20.4%) of the cases and 5/50(10%) of the controls. The risk of lung epithelium
chronic inflammation associated with exposure to Shabbah smoke, OR (95%CI) was 2.3065 (0.8710 to 6.1078), P = 0.0925, z statistic
= 1.682. Conclusion: Exposure to Shabbah smoke affects the lung epithelial tissue leading to squamous metaplasia and chronic
inflammatory cells infiltrate. Chronic inflammatory cells infiltrate significantly increase with the increase of duration of exposure to
Shabbah smoke.
Keywords: air pollution, Smoke, cytology, lung epithelium, Saudi Arabia