Wood dust exposure and the risk of upper aerodigestive and respiratory cancers in males

Background: Wood dust (WD) has been designated a human carcinogen that can cause sino-nasal cancers. However, evidence of its association with other upper aero-digestive tract and respiratory (UADR) cancers is inconsistent. Objective: To examine the relationship between WD exposure and the risk of different histological subtypes of UADR cancers. Methods: In a hospital-based case-control study conducted at Roswell Park Cancer Institute, Buffalo, NY, USA, an examination was carried out to determine the effect of self-reported WD exposure on 1522 male UADR cancer cases (241 oral and oropharyngeal, 90 nasal cavity, nasopharyngeal and hypopharyngeal, 124 laryngeal, 809 lung and tracheal and 258 oesophagus and gastric cardia) and 1522 male controls, frequency matched on age and smoking history. Odds ratios (OR) were calculated after adjusting for relevant risk factors including tobacco smoking. Results: The results show that regular WD exposure was associated with a statistically significant increased risk of 32% for all UADR cancers (OR 1.32; 95% Cl 1.01 to 1.77; p-trend = 0.05) and 69% for lung cancer alone (OR 1.69; 95% Cl 1.20 to 2.36; p-trend = 0.007). WD was associated with an 82-93% increased risk of squamous cell, small cell and adenocarcinoma of the lung and more than twice the risk of developing squamous cell carcinoma of the nasal cavity, nasopharynx and hypopharynx, with a significant dose-response relationship. Oral and oropharyngeal cancers showed a non-significant increase in risk. A significant increase in risk of laryngeal and lung cancers was noted for subjects regularly exposed to WD for >20 years. Cancers of the oesophagus and gastric cardia did not show any risk associated with WD. WD was associated with a significantly greater risk of UADR cancers among people who had ever smoked than never smokers. Conclusion: WD exposure is a potential risk factor for UADR cancers, especially for cancers of the nasal cavity, nasopharynx, larynx and lung.