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BACKGROUND: The potential role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high‐incidence areas. METHODS: The authors conducted a population‐based case‐control study, consisting of 2514 incident NPC cases and 2586 randomly selected population controls, in southern China from 2010 to 2014. Occupational history and other covariates were self‐reported using a questionnaire. Multivariate logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of NPC associated with occupational exposures. Restricted cubic splines were used to evaluate potentially nonlinear duration‐response relations. RESULTS: Individuals who had exposure to occupational dusts (OR, 1.45; 95% CI, 1.26‐1.68), chemical vapors (OR, 1.37; 95% CI, 1.17‐1.61), exhausts/smokes (OR, 1.42; 95% CI, 1.25‐1.60), or acids/alkalis (OR, 1.56; 95% CI, 1.30‐1.89) in the workplace had an increased NPC risk compared with those who were unexposed. Risk estimates for all 4 categories of occupational exposures appeared to linearly increase with increasing duration. Within these categories, occupational exposure to 14 subtypes of agents conferred significantly higher risks of NPC, with ORs ranging from 1.30 to 2.29, including dust from metals, textiles, cement, or coal; vapor from formaldehyde, organic solvents, or dyes; exhaust or smoke from diesel, firewood, asphalt/tar, vehicles, or welding; and sulfuric acid, hydrochloric acid, nitric acid, and concentrated alkali/ammonia. CONCLUSIONS: Occupational exposures to dusts, chemical vapors, exhausts/smokes, or acids/alkalis are associated with an excess risk of NPC. If the current results are causal, then the amelioration of workplace conditions might alleviate the burden of NPC in endemic areas. LAY SUMMARY: The role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high‐incidence areas.The authors conducted a population‐based study with 2514 incident NPC cases and 2586 population controls in southern China and observed that occupational exposures were associated with an increased risk of NPC.Duration‐response trends were observed with increasing duration of exposure.These findings provide new evidence supporting an etiologic role of occupational exposures for NPC in a high‐incidence region. Occupational exposures are associated with an increased risk of nasopharyngeal carcinoma, and the association is primarily driven by 14 subtypes of occupational agents. Duration‐response trends are observed with increasing duration of exposure. [ABSTRACT FROM AUTHOR]

Background: An association between a nonmedicinal herbal diet and nasopharyngeal carcinoma (NPC) has often been hypothesized but never thoroughly investigated.Methods: This study enrolled a total of 2469 patients with incident NPC and 2559 population controls from parts of Guangdong and Guangxi Provinces in southern China between 2010 and 2014. Questionnaire information was collected on the intake of traditional herbal tea and herbal soup as well as the specific herbal plants used in soups and other potentially confounding lifestyle factors. Multivariate logistic regression models were used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the NPC risk in association with herbal tea and soup intake.Results: Ever consumption of herbal tea was not associated with NPC risk (OR, 1.03; 95% CI, 0.91-1.17). An inverse association was observed for NPC among ever drinkers of herbal soup (OR, 0.78; 95% CI, 0.67-0.90) but without any monotonic trend with an increasing frequency or duration of herbal soup consumption. Inverse associations with NPC risk were detected with 9 herbal plants used in herbal soup, including Ziziphus jujuba, Fructus lycii, Codonopsis pilosula, Astragalus membranaceus, Semen coicis, Smilax glabra, Phaseolus calcaratus, Morinda officinalis, and Atractylodes macrocephala (OR range, 0.31-0.79).Conclusions: Consuming herbal soups including specific plants, but not herbal tea, was inversely associated with NPC. If replicated, these results might provide potential for NPC prevention in endemic areas. [ABSTRACT FROM AUTHOR]

Background: The association between smoking and nasopharyngeal carcinoma (NPC) is still uncertain. The aim of this study was to validate smoking effect on NPC and explore if smoking can induce NPC by persistently reactivating EBV in long‐term based on a prospective cohort design. Methods: A NPC screening cohort with 10 181 eligible residents in Sihui city, southern China was conducted from 2008 to 2015. The smoking habit was investigated through the trained interviewers and EBV antibodies (VCA‐IgA, EBNA1‐IgA) as screening markers were tested periodically. New NPC cases were identified through local cancer registry. Cox's regression model was used to estimate the adjusted hazard ratios (aHRs) of smoking on NPC incidence. In the non‐NPC participants, the associations between smoking and EBV seropositivity in different periods were assessed by logistic regression and generalized estimating equations (GEE). Results: With a median of 7.54 years, 71 NPCs were diagnosed ≥1 year after recruitment. Compared with never smokers, the aHRs of developing NPC among ever smokers were 3.00 (95%CI: 1.46‐6.16). Stratified by sex, the HRs of ever smoking were 2.59 (95%CI: 1.07‐6.23) for male and 3.75 (95%CI: 1.25‐11.20) for female, respectively. Among the non‐NPC individuals, ever smoking was not only associated with EBV seropositivity at baseline, but also in the 3‐5 years of follow up, with adjusted odds ratios (aORs) of 1.68 (95%CI: 1.29‐2.18) for VCA‐IgA and 1.92 (95%CI: 1.42‐2.59) for EBNA1‐IgA. Among the smokers who were tested EBV antibodies at least twice, the similar results were obtained using GEE. Conclusion: Smoking could significantly increase the long‐term risk of NPC in southern China, partly by persistently reactivating EBV. [ABSTRACT FROM AUTHOR]

Whether the association between body size or shape and nasopharyngeal carcinoma (NPC) risk exists or varies by age‐specific body size indicators is unclear. In a population‐based case–control study conducted in Southern China between 2010 and 2014, self‐reported height, weight, and body shape at age 20 and 10 years before interview were collected from 2448 histopathologically confirmed NPC cases and 2534 population‐based controls. Body mass index (BMI) was categorized according to the World Health Organization guidelines for Asian populations: underweight (<18.5 kg/m2), normal weight (18.5‐22.9 kg/m2), overweight (23.0‐27.4 kg/m2), and obese (≥27.5 kg/m2). Multivariate odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic regression. Furthermore, restricted cubic spline analysis was employed to examine nonlinear effects of BMI and body shape as continuous covariates. Underweight vs normal weight at age 20 years was associated with a 22% decreased NPC risk (OR, 0.78; 95% CI, 0.67, 0.90), whereas obesity was not significantly associated with NPC risk. Associations with BMI 10 years before the interview were similar. Having the leanest body shape at age 20 years, compared with the mode was not significantly associated with NPC risk (OR, 0.85; 95% CI, 0.62, 1.16), but having a larger body shape was associated with an elevated risk (OR, 1.25; 95% CI, 1.03, 1.52). Increasing BMI revealed positive trends with NPC risk. Despite some indication of significant findings, evidence for a strong association between BMI or body shape and NPC risk is still limited. [ABSTRACT FROM AUTHOR]

Background: To the authors' knowledge, no studies to date have explored familial risks of nasopharyngeal carcinoma (NPC) in detail and quantified its lifetime risk in high-incidence populations.Methods: The authors conducted a population-based case-control study of 2499 NPC cases and 2576 controls randomly selected in southern China from 2010 through 2014. Unconditional logistic regression was used to estimate multivariable-adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) associated with a family history of NPC. In addition, the authors compiled a reconstructed cohort comprising 40,781 first-degree relatives of cases and controls to calculate the lifetime cumulative risk of NPC.Results: Individuals with a first-degree family history of NPC were found to be at a >4-fold risk of NPC (OR, 4.6; 95% CI, 3.5-6.1) compared with those without such a history, but had no excess risk of other malignancies. The excess risk was higher for a maternal than a paternal history and was slightly stronger for a sibling compared with a parental history, and for a sororal than a fraternal history. Among relatives of cases, the cumulative risk of NPC up to age 74 years was 3.7% (95% CI, 3.3%-4.2%), whereas that among relatives of controls was 0.9% (95% CI, 0.7%-1.2%). Cumulative risk was higher in siblings than in parents among relatives of cases, whereas no such difference was noted among relatives of controls.Conclusions: Individuals with a family history of NPC have a substantially higher risk of NPC. These relative and cumulative risk estimates can guide the development of strategies for early detection and clinical consultation in populations with a high incidence of NPC. Cancer 2017;123:2716-25. © 2017 American Cancer Society. [ABSTRACT FROM AUTHOR]

BACKGROUND The utility of circulating Epstein-Barr Virus (EBV) DNA as a tumor marker for nasopharyngeal carcinoma (NPC) detection suggests that it might improve the diagnostic performance of anti-EBV antibody markers in NPC screening. In this study, the authors evaluated whether circulating EBV DNA load is capable of distinguishing NPC patients from high-risk individuals who have positive anti-EBV antibodies. METHODS In a population-based NPC screening trial in Sihui City and Zhongshan City, Guangdong Province, China, the authors previously identified 862 high-risk participants with 2 screening markers, immunoglobulin A (IgA) antibodies to EBV capsid antigen (VCA/IgA) and nuclear antigen-1 (EBNA1/IgA). In the current study, real-time polymerase chain reaction was used to measure the baseline plasma EBV DNA load among 825 participants (97%). Follow-up was extended to the end of 2011 to evaluate the diagnostic and predictive values of plasma EBV DNA load. RESULTS By using 0 copies/mL as the cutoff value, plasma EBV DNA had a sensitivity of 86.8% (33 of 38 patients) for NPC detected within the first year of follow-up, yielding a positive predictive value of 30% (33 of 110 participants) and a negative predictive value of 99.3% (696 of 701 participants). The patients who had early stage NPC had lower sensitivity (81.5%; 22 of 27 patients) than those who had advanced NPC (100%; 11 of 11 patients). For the 14 patients who had NPC detected after 1 year of follow-up, only 50% (7 of 14 patients) tested positive for EBV DNA at baseline. CONCLUSIONS The plasma EBV DNA load may improve the accuracy of diagnosing NPC in high-risk individuals, but it appears to have limited value in screening patients who have early stage NPC and predicting NPC development. Cancer 2014;120:1353-1360. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]