Wood Dust Exposure and Risk of Sinonasal and Nasopharyngeal Cancer: A Meta-Analysis

Research Article

Austin J Dermatolog. 2014;1(2): 1009.

Wood Dust Exposure and Risk of Sinonasal and Nasopharyngeal Cancer: A Meta–Analysis

Jia-Xiang Zhang1, Hui Xu2, Tong Shen3 and Qi-Xing Zhu1,2*

1Department of Occupational Health and Environmental Health, Anhui Medical University, China

2Institute of cancer prevention, PR China

3Institute of Dermatology, Anhui Medical University, PR China

*Corresponding author: Qixing Zhu, Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, 230032, PR China

Received: April 01, 2014; Accepted: May 12, 2014; Published: May 14, 2014


Objectives: In order to examine association between wood dust exposure and sin nasal and nasopharyngeal cancer.

Methods: We performed a systematic search of the literature. Both random and fixed effects were used to calculate odd ratios (ORs) and 95% confidence intervals (95%CIs) of each study.

Results: A significant increased risk of sinonasal and nasopharyngeal cancer was associated with wood dust exposure. The ORs for sinonasal cancer were 7.78 (CI: 2.97–20.25) among adenocarcinoma studies and 1.18 (CI: 0.64– 2.19) among squalors cell carcinoma studies. Contrary to women (OR=2.11, CI: 0.71–6.32), an elevated risk of sinonasal cancer was observed among men (OR=2.29, CI: 1.55–3.41). The OR for nasopharyngeal cancer was 1.87 (CI: 1.57–2.38).

Conclusion: Wood dust exposure was a high risk associated with sinosnasal and nasopharyngeal cancer. Except for female and squalors cell carcinoma studies in sinosnasal cancer, all stratifications in our meta–analysis present a significant risk between sinosnasal or nasopharyngeal cancer and wood dust exposure.

Keywords: Wood Dust; Sinonasal; Nasopharyngeal; Cancer; Meta– Analysis


Sinonasal and nasopharyngeal cancer had often been related to occupational exposure. Sinonasal cancer was a rare disease with annual incidence rates around 1 per 100000 in many countries [1]. The association between nasal cancer and wood dust exposure was first concentrated from a clustering of this rare cancer in High Wycombe, a furniture–making center in central England [2], and various studies have confirmed the finding from then on [3–6]. Exposure to wood dust was also recognized as a risk factor for nasopharyngeal [7]. The study in Britain and United States involving approximately 29000 wood workers revealed evidence of association between exposure to wood dust and the risk of nasopharyngeal cancer [8].

Wood dust was classified as a human carcinogen by the International Agency for Research on cancer in October, 1994 [9]. Wood workers did their jobs in different occupations such as carpenters; sawmill workers and small boat constructors. All of them were exposed to a certain amount of wood dust. A reanalysis of data from five cohorts of workers in wood–related industries confirmed the association between sinonasal cancer and wood dust exposure [8]. Especially nasal adenocarcinoma showed a strong correspondence with occupational exposure to hardwood dust in furniture industries [10]. Another Thai population study identified that wood dust might be associated with an increase risk of nasopharyngeal cancer [11]. Thomas [12] took a further analysis of exposure to wood dust which focused on the 142 cases of nasopharyngeal cancer. After adjusted for the main risk factor, there was only weak evidence of an association with ever working in a job with potential exposure (OR=1.5; 95% CI: 0.7 to 3.3). Hence we preformed a meta–analysis of all eligible casecontrol studies to derive a more precise estimation of the association to help us better understand that the wood dust exposure possible influence on sinonasal and nasopharyngeal cancer. Our study mostly referred to sinonasal and nasopharyngeal cancer occurring in an occupational setting.


Data source and searches

We searched articles with search term “sinonasa” or “nasopharyngeal”, “cancer” or “carcinoma” and “case–control study”, in the Medline database utilizing Pub Med engine, with the search from January 1, 1980 through April 1, 2013. We assessed all associated publications to retrieve eligible literature. And their reference lists were searched manually to identify other relevant publications. All of the results were limited to case–control study and English–language papers.

Data inclusion and exclusion criteria

We included studies which present original data from case control studies. The following inclusion criteria were used to choose studies for further analysis: (1) published in peer–reviewed journals, (2) described explicitly occupational expose to wood dust, (3) diagnosed sinonasal and nasopharyngeal cancer exactly and (4) provided odd ratios (ORs) or gave enough data to allow us to calculate it. Meanwhile we selected studies that analyzed data on wood workers as a subgroup analysis.

Data extraction and quality assessment

Two reviewers abstracted information from all eligible publications independently, according to the inclusion and exclusion criteria mentioned above. The same two reviewers accessed the quality of the studies independently according to the predefined score scale for quality assessment (Table1). These scores were based on traditional epidemiological considerations, cancer genetic issues and Newcastle–Ottawa scale [13–15]. Both reviewers resolved any disagreement by discussion. Total scores ranged from 0 (worst) to 15 (best). Reports scoring <10 were classified as “low quality”, and those 10 as “high quality”.

Statistical analysis

Crude odd ratios (ORs) and 95% confidence intervals (CIs) were used to access the strength of association between sinonasal and nasopharyngeal cancer and wood dust exposure in each case–control study. We then pooled them together to be in a subsequent study. The pooled ORs were performed according to both fixed and random effects. We also preferentially used the latter when heterogeneity was present. The fixed effects model assumed that the results and that their variations were due to sampling only, and that was to say no variance between studies. The random effects model, on the contrary, assumed that study results are heterogeneous. The random effects model yields pooled results have wider confidence intervals which are less precise in nature but are closer to the true value if heterogeneity exists [15]. DerSimonian and Laird Q test was used to check for heterogeneity.The null hypothesis of the test is absence of heterogeneity. To quantify it, we subsequent calculated the proportion of the total variance depend on “between–study variance (Ri statistic)” [16]. We also analyzed the subgroup of studies defined by study characteristics such as type of controls (hospital–based or population–based), gender and ethnicity.