Occupational risk factors for nasopharyngeal carcinoma in Hong Kong Chinese: a case-referent study

This study aimed to investigate the occupational risk factors for nasopharyngeal carcinoma (NPC) in Hong Kong Chinese.

We conducted a case-referent study with 352 incident cases and 410 referents recruited between June 2010 and December 2012. Full occupational histories were obtained via face-to-face interviews. Unconditional logistic regressions were performed to estimate the odds ratios (ORs) for NPC associated with occupational risk factors.

Workers of craft related trades and elementary occupations were at elevated NPC risk with the adjusted ORs of 2.09 [95% confidence interval (CI) 1.09, 4.01] and 2.14 (95% CI 1.04, 4.41), respectively, compared with those clerical support workers as the reference group. Occupational exposures to cotton dust, chemical fumes, and welding fumes were significantly associated with increased NPC risk after adjustment for confounders [adjusted ORs (95% CIs) 1.93 (1.13, 3.28), 13.11 (1.53, 112.17), and 9.18 (1.05, 80.35), respectively]. We also observed significant exposure-response relationship for the duration of exposure to cotton dust (P for trend = 0.0175). Those with occupational exposure to cotton dust for 15 years or more were at significantly increased risk of NPC (adjusted OR 2.08, 95% CI 1.01, 4.28).

This study indicates that employment in craft related trades and elementary occupations, as well as occupational exposures to chemical fumes, welding fumes, and cotton dust may be associated with an increased risk of NPC. Further epidemiological studies remain warranted to clarify the roles of specific occupational risk factors on NPC development.