Occupational risk factors for sinonasal inverted papilloma: a case-control study

Sinonasal inverted papilloma (IP) is an uncommon benign tumour characterised by frequent recurrence and, in approximately 10% of cases, by neoplastic transformation. IP aetiology is unknown but human papillomavirus is detectable in about one quarter of tumours. As some occupational hazards have been reported to be possible risk factors for IP, the aim of this study was to assess risk for sinonasal IP associated with prior exposure to suspected occupational risk factors for sinonasal malignancies.

Between 1996 and 2007, data on incident cases were collected from hospitals throughout the Piedmont region of Italy by the regional sinonasal cancer registry. A questionnaire on occupational history, completed by 127 cases and 337 hospital controls, was used to assign previous exposure to a list of 17 occupational hazards. The relationship between IP and cumulative exposure to these hazards was explored using unconditional logistic regression to statistically adjust for age, sex, area of residence, smoking and co-exposures.

The risk of IP was significantly increased for ever exposure to welding fumes (OR 2.14) and organic solvents (OR 2.11) after controlling for potential confounders. For organic solvents only, a significant association with continuous cumulative exposure and a significant trend in risk across ordered cumulative exposure categories was found.

The present study revealed a significant association and a significant dose-response relationship between occupational exposure to organic solvents and IP. The lack of a dose-response relationship for welding fumes suggests that the observed association with ever exposure should be interpreted with caution.