ORIGINAL ARTICLE Occupational Exposures to Aluminum and Iron and Risk of Lung Epithelium Atypia in Sudan Hussain Gadelkarim Ahmed, B.Sc., M.Sc., Ph.D., 1 * Tagreed Ahmed Mahmoud B.Sc., 2 and Ibrahim A. Ginawi, M.B.B.S., M.P.H., M.D. 3 This study investigated the risk of lung cytological atypical changes in regards to occupational exposure to aluminum and iron. Detailed job histories were elicited from 130 incident cases with confirmed exposure to aluminum (50) or iron (80) and 157 population controls (nonexposed). Cytological atypia in sputum (dysplasia) was identified in four cases and none of controls (RR ¼10.8550; 95% CI ¼ 0.5898 to 199.7815, P ¼ 0.1086), hence, metaplasia was observed among 15 (11.5%) of the cases and 10 (6%) of controls (RR ¼ 1.8115; 95% CI ¼ 0.8424–3.8956; P ¼ 0.1283). Evidences of viral infection were observed in 18 (14%) of the cases and 8 (5%) of controls (RR ¼ 2.7173; 95% CI ¼ 1.2213–6.0460; P ¼ 0.0143). Moniliasis was observed in 28 (22%) of the cases and 19 (12%) of controls (RR ¼ 1.6632; 95% CI ¼ 0.9728–2.8435; P ¼ 0.06). Cross-categorizations of alumi- num exposure and iron use suggest greater risk associated with iron exposure than aluminum in these workers. Diagn. Cytopa- thol. 2012;00:000–000. ' 2012 Wiley Periodicals, Inc. Key Words: aluminum; iron; lung; cytological atypia Introduction The most common risk factors of respiratory diseases especially lung cancer are smoking and environmental air pollution. 1 Smoking causing over 90% of lung cancers. 2 On the other hand, air pollution is confirmed as a major elevator for risk of lung cancer in polluted areas. 3 Several occupational carcinogens, including asbestos, aluminum, and polycyclic aromatic hydrocarbons have also been proven to increase the risk for lung cancer. 4,5 Many work settings could have exposed workers to carci- nogens, leading to an increased risk of lung and other cancers. Fifteen percent of male lung cancer cases that occur in industrialized countries are linked to occupation, which implies that lung cancer is the most frequent occu- pational cancer. 6 Inhalation of metal dust or fume can cause granulomatous lung diseases. Inhalation of Iron compounds causes siderosis, pneumoconiosis with little or no fibrosis. 7 Chronic inhalation of aluminum dust and fumes result in pulmonary aluminosis. 8,7 Evidence from occupational and environmental epidemiology studies using different designs, indicates that iron foundry work- ers have increased risk of developing lung cancer. 5 Sputum cytology examination is still an important method for diagnosing lung cancer, and it is simple to perform. For instance, cytotyping accuracy in a compari- son with histologic classification was very high. 9,10 Inhaled metal dust, particularly, aluminum and/or iron without defined means of protection is a highly prevalent occupational exposure and a recognized lung carcinogen. No previous studies have focused on such selected high- exposure occupational groups. This study investigated the relationship between occupational exposure to aluminum and iron and lung epithelia atypia in an occupationally diverse male population in Sudan. Materials and Methods This study investigated lung epithelium cells in sputum materials obtained from 287 apparently healthy volun- teers. Of the 287 study subjects, 130 were exposed to metal dust (ascertained as cases), and 157 were non- exposed (ascertained as controls). Of the 130 cases, 50 1 Department of Histopathology, University of Khartoum, Khartoum, Sudan 2 Department of Cytology, FMLs, University of Khartoum, Khartoum, Sudan 3 Department of Family and Community Medicine, College of Medi- cine, University of Hail, KSA *Correspondence to: Hussain Gadelkarim Ahmed, B.Sc., M.Sc., Ph.D., University of Khartoum, 102, Faculty of Medical Laboratory Sciences, Khartoum, Sudan. E-mail: hussaingad1972@yahoo.com Received 16 February 2012; Accepted 29 June 2012 DOI 10.1002/dc.22911 Published online in Wiley Online Library (wileyonlinelibrary.com). ' 2012 WILEY PERIODICALS, INC. Diagnostic Cytopathology, Vol 00, No 00 1