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Background: Oral Epstein-Barr virus (EBV) status reflects host EBV activity and potentially links to EBV-associated diseases, however, factors influencing oral EBV loads or reactivation, such as environmental exposures or host factors, are not fully understood.Methods: A 2-stage, multicenter, cross-sectional study of 6558 subjects from 21 administrative cities of southern China and 3 populations from representative geographical areas in China (referred to as the south, north, and northeastern populations) was performed. The relationships between demographical factors and environmental exposures to EBV loads were analyzed by logistic regression models.Results: Current smoking, with a dose-response effect, was found to be strongly associated with higher oral EBV loads in the pooled data, with an odds ratio of 1.58 (95% confidence interval, 1.39-1.79), as well as in each of the separate populations. The odds ratio increased to 3.06 when current smokers in southern China were compared to never smokers in northern China. Additionally, higher oral EBV loads tended to be detected in older participants, male participants, and participants in southern China.Conclusions: This study provided evidence linking the effect of host-environmental factors, particularly smoking, to oral EBV activity. It could strengthen our understanding of the possible causal roles of EBV-related diseases, which may help to prevent or mitigate EBV-associated diseases. [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]

Epstein-Barr virus (EBV) is one of the risk factors of nasopharyngeal carcinoma (NPC), and understanding the modifiable risk factors of EBV activation is crucial in the prevention of NPC. In this study, we aimed to investigate the association between solid fuel use and EBV seropositivity in a high-risk area of NPC. Our study was based on the baseline findings from an ongoing population-based prospective cohort in Sihui county in Southern China. We explored the association between current use of solid fuel in cooking and EBV seropositivity, and NPC-related EBV activation, using logistic regression models. Stratification analyses were further conducted to assess potential effect modifiers. We also examined the impact of frequency and duration of solid fuel use, and switch in fuel types, on EBV seropositivity among ever users. Of the 12,579 participants included in our analysis, 4088 (32.5%) were EBV seropositive and 421 (3.3%) were high risk for NPC-related EBV activation. Solid fuel use was associated with a higher risk of EBV seropositivity and NPC-related EBV activation, with odds ratios (ORs) of 1.33 (95%CI: 1.01, 1.76) and 1.81 (95%CI: 1.03, 3.18), respectively. Higher risk of EBV seropositivity was observed for those who did not use ventilation apparatus and those who consumed salted food. Among ever users, OR was highest for participants with more than 40 years of solid fuel exposure (1.17, 95%CI: 1.00–1.37) and who have been constantly using solid fuel (1.30, 95%CI: 0.96–1.75). We did not find a statistically significant impact of cooking frequency on EBV seropositivity. The identification of solid fuel as a risk factor for EBV activation is of great value for understanding the etiology of NPC. Our findings also have important public health implications given the fact that a third of the global population still lack access to clean cooking, especially in low resource settings. [Display omitted] • Solid fuel is associated with increased risk of EBV seropositivity and activation. • For ever-users, largest effect in those using solid fuel constantly over 40 years. • High risk of solid fuel among ventilator nonusers and those who consume salted food. [ABSTRACT FROM AUTHOR]

Objects: Nasopharyngeal carcinoma (NPC) incidence exhibits a remarkable sex disparity, with higher risk among males. Whether this pattern can be partly explained by female reproductive history is unclear.Methods: A population-based case-control study of NPC was conducted in southern China between 2010 and 2014, including 674 histopathologically verified female NPC cases and 690 female controls randomly selected from population-based registries. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression after adjusting for potential confounders.Results: Women who had 3, 4, or ≥5 pregnancies compared with 2 pregnancies were at significantly increased risk for NPC (ORs 1.56, 1.45 and 1.88, respectively). History of deliveries was similarly associated with a greater risk of NPC. These positive associations were more prominent in women who were younger than 50 years, had less than 10 years of education, or were white-collar workers. Increasing time since menopause was associated with a diminished NPC risk (Ptrend = 0.010). Women more than 15 years after menopause had a 0.35-fold (95% CI: 0.16-0.75) NPC risk compared with those 0-3 years after menopause.Conclusion: Contrary to our hypothesis, a history of pregnancy or delivery increased the risk of NPC and the risk decreased with increasing time since menopause. However, the non-linear relationship and no consistent risk patterns across strata indicate that the observed associations are unlikely to be causal, and may at least partially be ascribed to residual confounding by socioeconomic factors. [ABSTRACT FROM AUTHOR]

• Association of nasopharyngeal carcinoma (NPC) with lifelong residential exposures. • A population-based study of 2533 incident NPC cases and 2597 population controls. • Poorer residential conditions were associated with an increased risk of NPC. • Risk of NPC was stronger for residential exposures at an earlier age. • Risk of NPC increased with increasing duration of residential exposures. Given the role of exposures related to residence in the development of nasopharyngeal carcinoma (NPC) has not been well explored, present study aims to investigate the magnitude and pattern of associations for NPC with lifelong residential exposures. We carried out a multi-center, population-based case-control study with 2533 incident NPC cases and 2597 randomly selected population controls in southern China between 2010 and 2014. We performed multivariate logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of NPC associated with residential exposures. Compared with those living in a building over lifetime, risk of NPC was higher for individuals living in a cottage (OR: 1.56; 95% CI: 1.34–1.81) or in a boat (3.87; 2.07–7.21). NPC risk was also increased in individuals using wood (1.34; 1.03–1.75), coal (1.70; 1.17–2.47), or kerosene (3.58; 1.75–7.36) vs. using gas/electricity as cooking fuel; using well water (1.57; 1.34–1.83), river water (1.80; 1.47–2.21), or spring/pond/stream water (2.03; 1.70–2.41) vs. tap water for source of drinking water; living in houses with smaller-sized vs. larger windows in the bedroom (3.08; 2.46–3.86), hall (1.89; 1.55–2.31) or kitchen (1.67; 1.34–2.08); and increasing exposure to cooking smoke [(1.53; 1.20–1.94) for high exposure)] or burned incense [(1.59; 1.31–1.95) for daily use)]. Weighted Cox regression analysis corroborated these results. Poorer residential conditions and household air pollution are associated with an increased risk of NPC. Large-scale studies in other populations or longitudinal studies are warranted to further corroborate these findings. [ABSTRACT FROM AUTHOR]