Occupational exposure to wood dust and risk of nasopharyngeal cancer: A systematic review and meta-analysis

Introduction Nasopharyngeal cancer (NPC) is one of the most commonly occurring cancers in some regions. While wood dust is a confirmed human carcinogen, its association with NPC remains uncertain due to inconsistent findings in the related studies. We performed the first systematic review and meta-analysis on the epidemiological evidence to examine the association between occupational exposure to wood dust and the risk of NPC. Methods: In this meta-analysis study, the PubMed and Scopus databases were searched for English-language publications. seven case-control studies were included in the pooled analysis. Results: These studies were published between 1991 and 2016. The heterogeneity across the studies was significant (P = 0.06, I-2 = 50.4%). The results of the random effects model meta-analysis showed that there was a direct relationship between occupational exposure to wood dust and NPC (OR = 1.5 95% CI: 1.09-2.07). Among different histological subtypes of NPC, there was a significantly increased risk for the nonkeratinizing carcinoma following wood dust exposure (OR = 1.68, 95%CI: 1.03-2.74). We found no evidence of publication bias across studies according to the result of the Egger's test (P of bias = 0.073). Conclusions: This meta-analysis suggests that occupational exposure to wood dust can be associated with an increased risk of the nonkeratinizing carcinoma of the histological subtypes of nasopharyngeal cancer.