Abstract
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.