A prospective study of tobacco and alcohol use as risk factors for pharyngeal carcinomas in Singapore Chinese

Exclusive waterpipe smoking and the risk of nasopharynx cancer in Vietnamese men, a prospective cohort study

Tobacco smoking is carcinogenic to humans. Besides cigarettes, the most common form of tobacco smoking, there was sparse evidence of waterpipe's carcinogenicity-induced nasopharyngeal cancer (NPC). This study investigated the association between waterpipe smoking and NPC mortality. Our study followed up with 20,144 eligible man participants from nine northern Vietnam communes between 2007 and 2019. Face-to-face interviews were conducted to gather data on exclusive waterpipe and cigarette smoking and dietary intake using structured semi-quantitative food frequency and lifestyle questionnaires. Nasopharyngeal cancer was determined by accessing the medical records at the state health facilities. We estimated the Cox proportional hazard ratio and 95% confidence intervals, HR (95% CI). The proportion of never smokers, exclusive waterpipe, exclusive cigarette, and dual waterpipe and cigarette smokers was 55.8%, 14.5%, 16.6%, and 13.1%, respectively. Exclusively waterpipe smokers increased the risk of NPC death compared to exclusively cigarette smokers, HR (95% CI): 4.51 (1.25, 16.31), p = 0.022. A dose-dependent positive relationship between NPC and exclusive waterpipe smoking was significantly seen for higher intensity HR (95% CI): 1.35 (1.07, 1.71), earlier age of smoking initiation HR (95% CI): 1.26 (1.06, 1.50), longer duration HR (95% CI): 1.31 (1.04, 1.66), and the cumulative number of a smoke lifetime HR (95% CI): 1.37 (1.08, 1.74). We observed a significant positive association between exclusive waterpipe smoking and NPC in men. The findings suggested that waterpipe smoking is likely more harmful than cigarettes in developing this cancer. A firm tobacco control against waterpipe smoking is highly recommended.

Germline Variants Associated with Nasopharyngeal Carcinoma Predisposition Identified through Whole-Exome Sequencing

The current understanding of genetic susceptibility factors for nasopharyngeal carcinoma (NPC) is still incomplete. To identify novel germline variants associated with NPC predisposition, we analysed whole-exome sequencing data from 119 NPC patients from Singapore with a family history of NPC and/or with early-onset NPC, together with 1337 Singaporean participants without NPC. Variants were prioritised and filtered by selecting variants with minor allele frequencies of <1% in both local control (n = 1337) and gnomAD non-cancer (EAS) (n = 9626) cohorts and a high pathogenicity prediction (CADD score > 20). Using single-variant testing, we identified 17 rare pathogenic variants in 17 genes that were associated with NPC. Consistent evidence of enrichment in NPC patients was observed for five of these variants (in JAK2, PRDM16, LRP1B, NIN, and NKX2-1) from an independent case-control comparison of 156 NPC patients and 9770 unaffected individuals. In a family with five siblings, a FANCE variant (p. P445S) was detected in two affected members, but not in three unaffected members. Gene-based burden testing recapitulated variants in NKX2-1 and FANCE as being associated with NPC risk. Using pathway analysis, endocytosis and immune-modulating pathways were found to be enriched for mutation burden. This study has identified NPC-predisposing variants and genes which could shed new insights into the genetic predisposition of NPC.

Nationwide Alcohol-related visits In Singapore's Emergency departments (NAISE): A retrospective population-level study from 2007 to 2016

INTRODUCTION

Excessive alcohol consumption is associated with increased morbidity and mortality, and its societal impact is substantial. The Nationwide Alcohol-related visits In Singapore Emergency departments study aims to characterise trends in ED visits involving acute and chronic alcohol consumption between 2007 and 2016.

METHODS

Data from the Singapore Ministry of Health, comprising all ED visits in Singapore from 2007 to 2016, were used. The data were aggregated by year and analysed for changes in prevalence and rates of ED visits for acute and chronic alcohol consumption, broken down by age, gender and ethnicity.

RESULTS

Over the study period, the number of ED visits involving alcohol consumption increased 98.3%, from 2236 in 2007 to 4433 in 2016. During the same period, the rate per 100 000 population increased 62.4% from 48.7 to 79.1, and total ED-related costs rose by 140%, from 528 680 to 1 269 638 SGD. The increase in alcohol-related visits rates and costs was higher than non-alcohol-related visits rates and costs, which increased by 12.1% and 115% respectively. While trends in acute and chronic alcohol-related ED visits stayed stable amongst women, they rose substantially in men. Older men aged 50-69 show the highest rates and rate of increase for both acute and chronic alcohol-related ED visits.

DISCUSSION AND CONCLUSIONS

Alcohol-related visits contributed disproportionately to the increasing number of ED visits in Singapore between 2007 and 2016. Older men form the demographic with the highest rates and increase in rates of alcohol-related ED visits and form a potential group for targeted intervention.

Dose-Response Reduction in Risk of Nasopharyngeal Carcinoma From Smoking Cessation: A Multicenter Case-Control Study in Hong Kong, China

BACKGROUND

Cigarette smoking is associated with nasopharyngeal cancer (NPC) risk. Whether quitting reduces the risk is unclear. We investigated the associations of NPC with duration of and age at quitting in an endemic region.

METHODS

We investigated the associations between NPC and quitting in a multicenter case-control study in Hong Kong with 676 newly diagnosed NPC cases and 1,285 hospital controls between 2014 and 2017, using a computer-assisted self-administered questionnaire. Multivariable unconditional logistic regression yielded adjusted odds ratios (AORs) of NPC by quitting status, duration and age of quitting, combinations of duration and age of quitting, and quitting to smoking duration ratio, compared with current smoking.

RESULTS

Quitting (AOR: 0.72; 95% CI: 0.53-0.98) and never smoking (0.73, 0.56-0.95) were associated with lower NPC risk. NPC risk decreased with (i) longer quitting duration (p < 0.01), reaching significance after 11-20 (0.62, 0.39-0.99) and 21+ years (0.54, 0.31-0.92) of quitting; (ii) younger quitting age (p = 0.01), reaching significance for quitting at <25 years (0.49, 0.24-0.97); and (iii) higher quitting to smoking duration ratio (p < 0.01), reaching significance when the ratio reached 1 (0.60, 0.39-0.93). Quitting younger (age <25) appeared to confer larger reductions (49% for ≤10 years of quitting, 50% for 11+ years) in NPC risk than quitting at older ages (25+) regardless of quitting duration (16% for ≤10 years, 39% for 11+ years).

CONCLUSIONS

We have shown longer duration and younger age of quitting were associated with lower NPC risk, with dose-response relations. Our findings support including smoking as a cause of NPC. Stronger tobacco control measures and quitting services are needed to prevent NPC.

Smoking and nasopharyngeal cancer: individual data meta-analysis of six prospective studies on 334 935 men

BACKGROUND

The role of smoking in nasopharyngeal carcinoma (NPC) remains uncertain, especially in endemic regions. We conducted an individual participant data (IPD) meta-analysis of prospective cohort studies to investigate the associations between smoking exposure and risk of NPC.

METHODS

We obtained individual participant data of 334 935 male participants from six eligible population-based cohorts in NPC-endemic regions, including two each in Guangzhou and Taiwan, and one each in Hong Kong and Singapore. We used one- and two-stage approaches IPD meta-analysis and Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of NPC for smoking exposure adjusting for age and drinking status.

RESULTS

During 2 961 315 person-years of follow-up, 399 NPC evens were ascertained. Risks of NPC were higher in ever versus never smokers (HRone-stage = 1.32, 95% CI = 1.07-1.63, P = 0.0088; HRtwo-stage = 1.27, 1.01-1.60, 0.04). These positive associations appeared to be stronger in ever smokers who consumed 16+ cigarettes/day (HRone-stage = 1.67, 95% CI = 1.29-2.16, P = 0.0001), and in those who started smoking at age younger than 16 (2.16, 1.33-3.50, 0.0103), with dose-response relationships (P-values for trend = 0.0028 and 0.0103, respectively). Quitting (versus daily smoking) showed a small reduced risk (stopped for 5+ years: HRone-stage = 0.91, 95% CI = 0.60-1.39, P = 0.66; for former smokers: HRtwo-stage = 0.84, 0.61-1.14, 0.26).

CONCLUSIONS

This first IPD meta-analysis from six prospective cohorts in endemic regions has provided robust observational evidence that smoking increased NPC risk in men. NPC should be added to the 12-16 cancer sites known to be tobacco-related cancers. Strong tobacco control policies, preventing young individuals from smoking, would reduce NPC risk in endemic regions.

The Evolving Epidemiology of Nasopharyngeal Carcinoma

BACKGROUND

The epidemiology of nasopharyngeal carcinoma (NPC) has long been a source of fascination due to the malignancy's striking geographic distribution, the involvement of the oncogenic Epstein-Barr virus (EBV), the unique association with intake of Chinese-style salt-preserved fish, and etiologic heterogeneity by histologic subtype.

METHODS

This review summarizes the current epidemiologic literature on NPC, highlighting recent results from our population-based case-control study in southern China.

RESULTS

Findings from our case-control study provide new insight into the epidemiology of NPC, including a diminished role of Chinese-style salt-preserved fish, a profound impact of EBV genetic sequence variation, modest positive associations with passive smoking and household air pollution, and possible effects of oral health and the oral microbiome. Recent findings from other studies include a protective association with infectious mononucleosis, suggesting a causal role of early EBV infection; familial risk conferred by shared genetic variation in the host antibody-mediated immune response to EBV infection; and an unclear association with occupational exposure to formaldehyde.

CONCLUSIONS

To shed further light on the interplay of environmental, genetic, and viral causes of NPC, large pooled studies must accumulate sufficient cases with detailed exposure data.

IMPACT

New epidemiologic findings have reshaped the causal model for NPC.

Intake of Alcohol and Tea and Risk of Nasopharyngeal Carcinoma: A Population-Based Case-Control Study in Southern China

BACKGROUND

The potential effect of alcohol or tea intake on the risk of nasopharyngeal carcinoma (NPC) remains controversial.

METHODS

In a population-based case-control study in southern China, we assessed alcohol or tea intake from 2,441 histopathologically confirmed NPC cases and 2,546 controls. We calculated mean daily ethanol (g/day) and tea intake (mL/day). Fully adjusted ORs with 95% confidence intervals (CI) were estimated using logistic regression; potential dose-response trends were evaluated using restricted cubic spline analysis.

RESULTS

Compared with nondrinkers, no significantly increased NPC risk in men was observed among current alcohol drinkers overall (OR, 1.08; 95% CI, 0.93-1.25), nor among current heavy drinkers (OR for ≥90 g/day ethanol vs. none, 1.32; 95% CI, 0.95-1.84) or former alcohol drinkers. Current tea drinking was associated with a decreased NPC risk (OR, 0.73; 95% CI, 0.64-0.84). Compared with never drinkers, those with the low first three quintiles of mean daily current intake of tea were at significantly lower NPC risk (OR, 0.53, 0.68, and 0.65, respectively), but not significant for the next two quintiles. Current daily tea intake had a significant nonlinear dose-response relation with NPC risk.

CONCLUSIONS

Our study suggests no significant association between alcohol and NPC risk. Tea drinking may moderately reduce NPC risk, but the lack of a monotonic dose-response association complicates causal inference.

IMPACT

Tea drinking might be a healthy habit for preventing NPC. More studies on biological mechanisms that may link tea with NPC risk are needed.

Alcohol consumption, drinking patterns and cancer incidence in an Australian cohort of 226,162 participants aged 45 years and over

BACKGROUND

Although overall alcohol consumption is known to increase the risk of a number of cancers internationally, evidence for Australia and evidence regarding the pattern of drinking and cancer risk is limited.

METHODS

Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cancer risk in relation to overall alcohol consumption (drinks/week) and pattern of drinking were calculated using Cox proportional hazard regressions for 226,162 participants aged ≥45 years (2006-2009) in the 45 and Up Study, an Australian prospective cohort study. Incident primary cancer cases were ascertained by linkage to the New South Wales Cancer Registry to 2013 by the Centre for Health Record Linkage.

RESULTS

Over a median of 5.4 years, 17,332 cancers were diagnosed. Increasing levels of alcohol intake were associated with increased risk of cancers of the upper aerodigestive tract (1.19; 1.10-1.29), mouth and pharynx (1.18; 1.08-1.29), oesophagus (1.22; 1.04-1.43), colorectum (1.09; 1.04-1.15), colon (1.13; 1.06-1.20), liver (1.22; 1.04-1.44) and breast (1.11; 1.02-1.21). Breast cancer risk was marginally associated with drinking pattern, with higher risk when intake was concentrated on 1-3 days/week compared to the same amount spread over 4-7 days (P_interaction = 0.049).

CONCLUSIONS

Alcohol consumption confers a significant risk of cancer, and drinking pattern may be independently related to breast cancer risk.

Risk factors for Epstein Barr virus-associated cancers: a systematic review, critical appraisal, and mapping of the epidemiological evidence

BACKGROUND

Epstein Barr Virus (EBV) infects 90%-95% of all adults globally and causes ~ 1% of all cancers. Differing proportions of Burkitt's lymphoma (BL), gastric carcinoma (GC), Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC) are associated with EBV. We sought to systematically review the global epidemiological evidence for risk factors that (in addition to EBV) contribute to the development of the EBV-associated forms of these cancers, assess the quality of the evidence, and compare and contrast the cancers.

METHODS

MEDLINE, Embase and Web of Science were searched for studies of risk factors for EBV-associated BL, GC, HL and NPC without language or temporal restrictions. Studies were excluded if there was no cancer-free comparator group or where analyses of risk factors were inadequately documented. After screening and reference list searching, data were extracted into standardised spreadsheets and quality assessed. Due to heterogeneity, a narrative synthesis was undertaken.

RESULTS

9916 hits were retrieved. 271 papers were retained: two BL, 24 HL, one GC and 244 NPC. The majority of studies were from China, North America and Western Europe. Risk factors were categorised as dietary, environmental/non-dietary, human genetic, and infection and clinical. Anti-EBV antibody load was associated with EBV-associated GC and BL. Although the evidence could be inconsistent, HLA-A alleles, smoking, infectious mononucleosis and potentially other infections were risk factors for EBV-associated HL. Rancid dairy products; anti-EBV antibody and EBV DNA load; history of chronic ear, nose and/or throat conditions; herbal medicine use; family history; and human genetics were risk factors for NPC. Fresh fruit and vegetable and tea consumption may be protective against NPC.

CONCLUSIONS

Many epidemiological studies of risk factors in addition to EBV for the EBV-associated forms of BL, GC, HL and NPC have been undertaken, but there is a dearth of evidence for GC and BL. Available evidence is of variable quality. The aetiology of EBV-associated cancers likely results from a complex intersection of genetic, clinical, environmental and dietary factors, which is difficult to assess with observational studies. Large, carefully designed, studies need to be strategically undertaken to harmonise and clarify the evidence.

REGISTRATION

PROSPERO CRD42017059806.

Association Between Alcohol Consumption and Risk of Nasopharyngeal Carcinoma: A Comprehensive Meta-Analysis of Epidemiological Studies

BACKGROUND

Alcohol consumption is increasing all over the world, but whether it is an independent factor affecting the occurrence of nasopharyngeal carcinoma (NPC) is inconsistent in many studies. We aimed to explore the association between alcohol consumption and NPC risk by integrating existing evidence in a meta-analysis.

METHODS

We searched for relevant articles published up to August 2018 in PubMed, Cochrane Library, Web of Science, and China National Knowledge infrastructure (CNKI). The Newcastle-Ottawa scale was used to assess the quality of the included studies. Odds ratios (ORs) or relative risks were pooled to estimate the associations between alcohol consumption and NPC risk.

RESULTS

The meta-analysis of cohort studies showed no significant association between alcohol consumption and NPC, but pooled results from case-control studies indicated that ever drinking increased the probability of NPC versus nondrinking (OR = 1.10; 95% confidence interval [CI]: 1.01, 1.19). As compared with nondrinkers, high-frequency drinking (≥7 times/wk) increased the NPC probability (OR = 1.29; 95% CI: 1.05, 1.53) and low-frequency drinking (<7 times/wk) decreased the probability (OR = 0.77; 95% CI: 0.60, 0.94), as did shorter duration of drinking (<20 years) (OR = 0.64; 95% CI: 0.49, 0.79). On subgroup analyses, significant pooled results were observed for studies with high quality, with hospital-based controls and with adjustment for confounding factors, smoking, age, and sex.

CONCLUSIONS

The risk of NPC may increase with alcohol consumption. Ever drinking increased the risk versus nondrinking. Additionally, high-frequency drinking increased the risk, but low-frequency drinking decreased it to some extent. Further intensive studies based on well-designed methods are needed to examine the association.

Association Between Serum Cotinine Level and Serological Markers of Epstein-Barr Virus in Healthy Subjects in South China Where Nasopharyngeal Carcinoma Is Endemic

Introduction: Self-reported smoking has been associated with higher seropositivity for the IgA response to Epstein–Barr virus (EBV) viral capsid antigen (VCA-IgA) and transcription activator protein (Zta) in healthy men in southern China where nasopharyngeal carcinoma (NPC) is endemic. Results on the association of biochemically verified smoking status with EBV reactivation are scarce. We aimed to investigate the relations of serum cotinine level with serological markers of EBV in healthy women, in addition to men.

Methods: We collected information on demographic, lifestyle, environmental factors, and EBV serological markers in a cross-sectional study on 2,275 healthy subjects who were recruited from physical examination centers in Guangdong Province, China. In the present analysis, 901 subjects' serum cotinine levels have been measured by enzyme-linked immunosorbent assay (ELISA). Odds ratios (seropositivity of four EBV serological markers vs. seronegativity) for categorical serum cotinine levels were calculated by unconditional logistic regression with a group-specific confidence interval (CI).

Results: In women, compared with lower serum cotinine level (0–0.71 ng/ml), higher cotinine level (>0.71–1.20 ng/ml; >1.20–228.40 ng/ml) was associated but non-significantly with higher seropositivity for EBV VCA-IgA (age- and education-adjusted OR = 1.18, 95% CIs = 0.84–1.64, 1.06, 0.75–1.50). These associations remained but still non-significant after adjusting for 5-year age group, education, family history of cancer, consumption of tea, Chinese herbal tea, salted fish at childhood, and exposure to occupational dust, chemical, fume, and radiation (multivariable adjusted OR = 1.21, 95% CIs = 0.85–1.71, 1.09, 0.76–1.55). In men, compared with lower serum cotinine level (0–2.15 ng/ml), higher cotinine level (>2.15–103.6 ng/ml; >103.6–419.4 ng/ml) was significantly associated with higher seropositivity for EBV VCA-IgA and Zta-IgA (age- and education-adjusted OR = 2.16, 95% CIs = 1.37–3.41, 1.79, 1.11–2.90; 1.98, 1.17–3.34, 1.95, 1.14–3.34). The association remained significant after adjusting for potential confounders for Zta-IgA (OR = 2.32, 95% CI = 1.37–3.93 for >2.15–103.6, and 2.50, 1.43–4.38 for >103.6–419.4 ng/ml), but not for VCA-IgA (2.06, 1.29–3.27, and 1.61, 0.96–2.71).

Conclusions: Higher serum cotinine level is associated with higher seropositivity for EBV serological markers in healthy men in southern China. Such positive association was also observed in women but became non-significant. If confirmed to be causal, this finding has important implications for tobacco control and prevention of EBV-related disease, particularly for NPC.

Smoking can increase nasopharyngeal carcinoma risk by repeatedly reactivating Epstein-Barr Virus: An analysis of a prospective study in southern China

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.

Nasopharyngeal carcinoma: understanding its molecular biology at a fine scale

Among all cancers, the incidence of nasopharyngeal carcinoma (NPC) is quite high in the endemic regions. NPC is a head and neck cancer with poor survival rate, and is rare throughout most of the world but common in certain geographic areas, like southern Asia and some regions of North East India (Nagaland, Manipur, and Mizoram). A clear understanding of its etiology is still lacking, but NPC is widely suspected to be the result of both genetic susceptibility and exposure to environmental factors or Epstein-Barr virus infection. Diagnosis in the early stages needs a high index of clinical acumen, and, although most cross-sectional imaging investigations show the tumor with precision, confirmation is dependent on histology. This article reviews all related research reports on NPC histopathological classifications worldwide that have been published within the past 20 years. Genome-wide association studies suggested that there might be common disease mechanisms between that disease and NPC. Personalized management rules, quality assessment of life in patients, and an understanding of the essential mechanisms of recurrence could be directed toward research into recurrent NPC. Hence, this literature would offer otolaryngologists a deeper insight into the etiological and management aspects of NPC.

Joint effect of smoking and NQO1 C609T polymorphism on undifferentiated nasopharyngeal carcinoma risk in a North African population

BACKGROUND

Nasopharyngeal carcinoma (NPC) has a higher incidence in North Africa than in most parts of the world. In addition to environmental factors such as Epstein-Barr virus infection and chemical carcinogen exposure, genetic susceptibility has been reported to play a key role in the development of NPC. NAD(P)H: quinone oxidoreductase 1 is a cytosolic enzyme that protects cells from oxidative damage. A C to T transition at position 609 in the NQO1 gene (OMIM: 125860) has been shown to alter the enzymatic activity of the enzyme and has been associated with increased risk to several cancers. This study investigates for the first time the effect of this polymorphism on NPC susceptibility in a North African population.

METHODS

The NQO1 C609T polymorphism was genotyped using PCR-RFLP in 392 NPC cases and 365 controls from Morocco, Algeria, and Tunisia.

RESULTS

The allele frequencies and distributions of genotypes did not differ between cases and controls (p > 0.05). When stratifying according to smoking status, we observed two-fold higher NPC risk in ever-smokers carrying the CT or TT genotype. Multiple logistic regression analysis revealed that there was a significant interaction between T allele and smoking status (OR = 1.95, 95% CI = 1.20-3.19; interaction p = 0.007).

CONCLUSION

In this North African population, the functional NQO1 polymorphism was associated with a significantly higher risk of NPC among smokers and did not affect the risk among nonsmokers.

Human Papillomavirus and Oropharyngeal Cancer Among Indigenous Australians: Protocol for a Prevalence Study of Oral-Related Human Papillomavirus and Cost-Effectiveness of Prevention

Background

Oropharyngeal cancer is an important, understudied cancer affecting Aboriginal and Torres Strait Islander Australians. The human papillomavirus (HPV) is a significant risk factor for oropharyngeal cancer. Current generation HPV vaccines are effective against the 2 most common types of high-risk HPVs in cancer (hrHPVs 16/18).

Objectives

This study aims (1) to yield population estimates of oncogenic genotypes of HPV in the mouth and oropharynx of defined Aboriginal and Torres Strait Islander populations; (2) to estimate the proportion of oropharyngeal cancer attributable to HPV among these Australian citizens; (3) to estimate the impact of HPV vaccination as currently implemented on rates of oropharyngeal cancer among Aboriginal and Torres Strait Islander Australians; and (4) taking into account impact on oropharyngeal as well as cervical cancer, to evaluate efficacy and cost-effectiveness of targeted extended HPV vaccination to older ages, among our study population.

Methods

Our study design and operation is straightforward, with minimal impost on participants. It involves testing for carriage of hrHPV in the mouth and oropharynx among 1000 Aboriginal South Australians by simple saliva collection and with follow-up at 12 and 24 months, collection of sexual history at baseline, collection of information for estimating health state (quality-of-life) utilities at baseline, genotyping of viruses, predictive outcome and cost-effectiveness modeling, data interpretation and development of vaccination, and follow-up management strategies driven by the Aboriginal community.

Results

Participant recruitment for this study commenced in February 2018 and enrollment is ongoing. The first results are expected to be submitted for publication in 2019.

Conclusions

The project will have a number of important outcomes. Synthesis of evidence will enable generation of estimates of the burden of oropharyngeal cancer among Aboriginal and Torres Strait Islander Australians and indicate the likely effectiveness and cost-effectiveness of prevention. This will be important for health services planning, and for Aboriginal health worker and patient education. The results will also point to important areas where research efforts should be focused to improve outcomes in Aboriginal and Torres Strait Islander Australians with oropharyngeal cancer. There will be a strong focus on community engagement and accounting for the preferences of individuals and the community in control of HPV-related cancers. The project has international relevance in that it will be the first to systematically evaluate prevention of both cervical and oropharyngeal cancer in a high-risk Indigenous population taking into account all population, testing, and surveillance options.

Registered Report Identifier

RR1-10.2196/10503

Assessment of Somatization and Medically Unexplained Symptoms in Later Life

The assessment of medically unexplained symptoms and "somatic symptom disorders" in older adults is challenging due to somatic multimorbidity, which threatens the validity of somatization questionnaires. In a systematic review study, the Patient Health Questionnaire-15 (PHQ-15) and the somatization subscale of the Symptom Checklist 90-item version (SCL-90 SOM) are recommended out of 40 questionnaires for usage in large-scale studies. While both scales measure physical symptoms which in younger persons often refer to unexplained symptoms, in older persons, these symptoms may originate from somatic diseases. Using empirical data, we show that PHQ-15 and SCL-90 SOM among older patients correlate with proxies of somatization as with somatic disease burden. Updating the previous systematic review, revealed six additional questionnaires. Cross-validation studies are needed as none of 46 identified scales met the criteria of suitability for an older population. Nonetheless, specific recommendations can be made for studying older persons, namely the SCL-90 SOM and PHQ-15 for population-based studies, the Freiburg Complaint List and somatization subscale of the Brief Symptom Inventory 53-item version for studies in primary care, and finally the Schedule for Evaluating Persistent Symptoms and Somatic Symptom Experiences Questionnaire for monitoring treatment studies.

Lack of association between cigarette smoking and Epstein Barr virus reactivation in the nasopharynx in people with elevated EBV IgA antibody titres

BACKGROUND

Subjects with elevated Epstein-Barr virus (EBV) immunoglobulin A (IgA) titers have a higher risk of developing nasopharyngeal carcinoma (NPC), indicating that reactivation of EBV in the local mucosa might be important for NPC carcinogenesis. Cigarette smoking appears to be one of the environmental risk factors for NPC. However, it remains unclear whether smoking-induced nasopharyngeal carcinogenesis acts through reactivating EBV in the nasopharyngeal mucosa. Therefore, this study aims to investigate the association between cigarette smoking and nasopharyngeal EBV reactivation in a NPC high-risk population.

METHODS

A NPC high-risk cohort study, established from a population-based NPC screening program of 22,816 subjects, consisted of 1045 subjects with elevated serum IgA antibodies against EBV viral capsid antigen (VCA/IgA). Among high-risk subjects, information on detailed cigarette smoking history was collected among 313 male subjects. The associations between cigarette smoking and EBV antibody levels, EBV DNA load of the nasopharynx were analyzed.

RESULTS

No significant association was observed between either nasopharyngeal EBV DNA load or serum VCA/IgA titers and smoking status, age at smoking initiation, daily smoking intensity, smoking duration, cigarette type, or pack-years of smoking. Cigarette smoking characteristics in all subgroups did not correlate with nasopharyngeal EBV DNA positivity or EBV VCA/IgA seropositivity.

CONCLUSIONS

In a population at high risk of NPC, our study suggests that cigarette smoking is neither associated with nasopharyngeal EBV DNA load nor serum VCA/IgA antibody level. Smoking-associated NPC carcinogenesis may act through other mechanisms than reactivating nasopharyngeal EBV replication.

The incidence and prognosis of nasopharyngeal carcinoma patients with family history

Purpose

Epidemiological data showed that nasopharyngeal carcinoma (NPC) was a regional malignancy. It suggested that genetic factor may play an important role in tumorigenesis of NPC. The aim was to investigate the incidence and the prognosis of NPC patients with family history.

Methods

The clinical data of patients with NPC treated in Fudan University Shanghai Cancer Center from January 2008 to December 2012 were reviewed, and the patients with family history were selected. The prognosis of patients with family history was follow-up. The 5-year overall survival (OS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were analyzed by Kaplan-Meier and log-rank test. Cox proportional hazard model was used for multivariate analysis.

Results

There were 3.64% (135/3706) NPC patients with family history of NPC. Eighty-three percent (112/135) patients had only one family member suffering from NPC previously, and 74.1% (100/135) patients who had family history only in first-degree family members. Excluding five patients lost to follow-up, 130 patients were eventually used to analyze the prognosis. The 5-year OS, LRFS, and DMFS rates of all patients with family history were 84.1%, 83.4%, and 83.8%, respectively. There were no significant differences of OS, LRFS and DMFS between one relative group and at least two relatives group. In addition, the degree of NPC had no association with OS, LRFS and DMFS, respectively.

Conclusion

Our results showed that there was an incidence rate of 3.64% NPC patients with family history. These patients had a satisfied prognosis, and the prognosis of NPC patients with family history in different degree or numbers of relatives had no significant differences.

Cigarette smoking and the risk of nasopharyngeal carcinoma: a meta-analysis of epidemiological studies

OBJECTIVE

The role of cigarette smoking as an independent risk factor for patients with nasopharyngeal carcinoma (NPC) is controversial. We attempted to provide evidence of a reliable association between cigarette smoking and the risk of NPC.

DESIGN

Meta-analysis.

DATA SOURCES

PubMed online and the Cochrane Library of relevant studies published up to February 2016.

ELIGIBILITY CRITERIA

All studies had to evaluate the relationship between NPC and cigarette smoking with never smokers as the reference group.

OUTCOMES

The primary outcome was the adjusted OR, RR or HR of NPC patients comparing smoking with never-smoking; the second was the crude OR, RR or HR.

RESULTS

We identified 17 case-control studies and 4 cohort studies including 5960 NPC cases and 429 464 subjects. Compared with never smokers, current smokers and ever smokers had a 59% and a 56% greater risk of NPC, respectively. A dose-response relationship was identified in that the risk estimate rose by 15% (p<0.001) with every additional 10 pack-years of smoking, and risk increased with intensity of cigarette smoking (>30 cigarettes per day). Significantly increased risk was only found among male smokers (OR, 1.36; 95% CI 1.15 to 1.60), not among female smokers (OR, 1.58; 95% CI 0.99 to 2.53). Significantly increased risk also existed in the differentiated (OR, 2.34; 95% CI 1.77 to 3.09) and the undifferentiated type of NPC (OR, 1.15; 95% CI 0.90 to 1.46). Moreover, people who started smoking at younger age (<18 years) had a greater risk than those starting later for developing NPC (OR, 1.78; 95% CI 1.41 to 2.25).

CONCLUSIONS

Cigarette smoking was associated with increased risk of NPC, especially for young smokers. However, we did not find statistical significant risks of NPC in women and in undifferentiated type, which might warrant further researches.

Quantification of familial risk of nasopharyngeal carcinoma in a high-incidence area

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.

Associations of lifestyle and diet with the risk of nasopharyngeal carcinoma in Singapore: a case-control study

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a commonly diagnosed cancer in Southeast Asia. Many studies have examined the risk factors for NPC, yet the roles of some risk factors remain inconclusive. The purpose of this study was to examine associations between modifiable lifestyle factors and the risk of NPC in the Singaporean population.

METHODS

We conducted a case-control study in Singapore with 300 patients and 310 controls who were recruited between 2008 and 2012. Each control was selected and individually matched to each patient based on sex, ethnicity, and age (±5 years). A total of 290 pairs of cases and controls were matched successfully. We examined lifestyle factors such as tobacco smoking, alcohol drinking, various salted and preserved food consumption, and weaning practices.

RESULTS

After adjusting for covariates, multivariate analysis showed that those participants who were current smokers and had ever smoked tobacco had a higher risk of NPC than participants who had never smoked, with odds ratios (ORs) of 4.50 (95% confidence interval [CI] 2.58-7.86; P < 0.001) and 2.52 (95% CI 1.54-4.12; P < 0.001), respectively. Those who consumed salted vegetables at least once a week also showed a significantly increased risk of NPC than those who never or rarely consumed salted vegetables, with an OR of 4.18 (95% CI 1.69-10.38; P = 0.002).

CONCLUSION

Smoking (currently and ever-smoked) and consuming salted vegetables once a week or more were lifestyle risk factors for NPC, and changes of these factors for the better may reduce the risk of NPC.

European Code against Cancer 4th Edition: Alcohol drinking and cancer

Alcohol consumption is the third leading risk factor for disease and mortality in Europe. As evaluated by the International Agency for Research on Cancer (IARC) Monographs, a causal relationship is established for consumption of alcoholic beverages and cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum and female breast, even at low and moderate alcohol intakes. The higher the amount of alcohol consumed, the higher the risk of developing cancer. In Europe, an estimated 10% (95% CI: 7%-13%) of all cancer cases in men and 3% (95% CI: 1%-5%) of all cancer cases in women are attributable to alcohol consumption. Several biological mechanisms explain the carcinogenicity of alcohol; among them, ethanol and its genotoxic metabolite, acetaldehyde, play a major role. Taking all this evidence into account, a recommendation of the 4th edition of European Code against Cancer is: "If you drink alcohol of any type, limit your intake. Not drinking alcohol is better for cancer prevention."

Cancer incidence attributable to tobacco in Alberta, Canada, in 2012

BACKGROUND

Strong and consistent epidemiologic evidence shows that tobacco smoking causes cancers at various sites. The purpose of this study was to quantify the proportion and total number of site-specific cancers in Alberta attributable to tobacco exposure.

METHODS

The proportion of incident cancer cases attributable to active and passive tobacco exposure in Alberta was estimated with population attributable risks. Data from the Canadian Community Health Survey (CCHS) for 2000-2007 were used to estimate prevalence of active (current or former smoker) and passive (second-hand smoke) tobacco exposure in Alberta.

RESULTS

According to the 2000/01 CCHS, 29.1% and 38.6% of Albertans were estimated to be current and former smokers, respectively. According to the 2003 CCHS, 23.7% of Albertans who had never smoked reported regular second-hand exposure to tobacco. Population attributable risk estimates for tobacco-related cancer sites ranged from about 4% for ovarian cancer to 74% for laryngeal cancer. About 5% of incident lung cancers in men and women who never smoked could be attributed to passive tobacco exposure. Overall, 37.0% of tobacco-related cancers in Alberta (or 15.7% of all cancers) were estimated to be attributable to active tobacco smoking in 2012.

INTERPRETATION

A notable proportion of cancers associated with tobacco use were estimated to be attributable to active smoking in Alberta. Strategies to reduce the prevalence of active tobacco smoking in Alberta could have a considerable impact on future cancer incidence.

European Code against Cancer 4th Edition: Alcohol drinking and cancer

Alcohol consumption is the third leading risk factor for disease and mortality in Europe. The International Agency for Research on Cancer (IARC) Monographs provide strengthened evidence that the consumption of alcoholic beverages is causally associated with cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum and female breast, even for low and moderate alcohol intakes. The risk of cancer increases in a dose-dependent manner, and the higher the amount of alcohol consumed, the higher the risk of developing cancer. Several biological mechanisms explain the carcinogenicity of alcohol; among them, ethanol and its genotoxic metabolite acetaldehyde play a major role. Taking all this evidence into account, a recommendation of the 4th edition of the European Code against Cancer (ECAC) is: "If you drink alcohol of any type, limit your intake. Not drinking alcohol is better for cancer prevention."

Smoking and nasopharyngeal carcinoma mortality: a cohort study of 101,823 adults in Guangzhou, China

Background

Nasopharyngeal carcinoma (NPC), also known as Cantonese cancer, is rare worldwide, but has particularly high incidence in North Africa and Southeast Asia, especially in Guangdong, China, such as Guangzhou. Tobacco causes head and neck cancers, but nasopharyngeal carcinoma is not included as causally related to smoking in the 2014 United States Surgeon General’s report. Prospective evidence remains limited. We used Guangzhou Occupational Cohort data to conduct the first and robust prospective study on smoking and NPC mortality in an NPC high-risk region.

Methods

Information on demographic characteristics and smoking status was collected through occupational health examinations in factories and driver examination stations from March 1988 to December 1992. Vital status and causes of deaths were retrieved until the end of 1999. Cox proportional hazard model was used to assess the association of smoking with NPC mortality.

Results

Of 101,823 subjects included for the present analysis, 34 NPC deaths occurred during the average 7.3 years of follow up. The mean age (standard deviation) of the subjects was 41 (5.7) years. Compared with never smokers, the hazard ratio (HR) of NPC mortality was 2.95 (95 % confidence interval 1.01–8.68; p = 0.048) for daily smokers and 4.03 (1.29–12.58; p = 0.016) for smokers with more than 10 pack-years of cumulative consumption, after adjusting for age, sex, education, drinking status, occupation and cohort status and accounting for smoking-drinking interaction. The risk of NPC mortality increased significantly with cigarettes per day (p for trend = 0.01) and number of pack-years (p for trend = 0.02).

Conclusions

In this first and largest cohort in a high NPC risk region, smoking was associated with higher NPC mortality. The findings have shown statistically significant dose–response trend between smoking amount and smoking cumulative consumption and the risk of NPC mortality, but due to the small event number, further studies with larger sample size are needed to confirm the findings in the present study. Our results support that smoking is one of the risk factors likely to be causally associated with NPC mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1902-9) contains supplementary material, which is available to authorized users.

Tobacco smoking, family history, and the risk of nasopharyngeal carcinoma: a case-referent study in Hong Kong Chinese

PURPOSE

This study aimed to investigate the associations of tobacco smoking and family history of nasopharyngeal carcinoma (NPC) with the risk of NPC in Hong Kong Chinese.

METHODS

Between June 2010 and December 2012, we conducted a case-referent study with 352 incident cases and 410 referents in Hong Kong. We collected information on tobacco smoking and family history of NPC via face-to-face interviews.

RESULTS

There were 174 (49.4%) and 131 (32.0%) ever-smokers among cases and referents, respectively. The adjusted odds ratio (OR) for NPC related to current smoking was 1.67 [95% confidence interval (CI) 1.06, 2.61]. Exposure-response relationships were observed between years and total pack-years of smoking, and NPC risk (p = 0.001 and p = 0.018, respectively). History of NPC in first-degree relatives was associated with an increased NPC risk (adjusted OR = 4.52, 95% CI 2.39, 8.55). The increased NPC risk associated with sibling history (adjusted OR = 6.80, 95% CI 2.63, 17.56) was higher than that for parental history (adjusted OR = 3.04, 95% CI 1.27, 7.25). The adjusted OR for ever-smokers with family history using never-smokers without family history as the reference was 4.54 (95% CI 1.67, 12.34).

CONCLUSIONS

This study verified the important roles of tobacco smoking and family history on NPC risk among Hong Kong Chinese. The provided evidence supported the knowledge that both environmental exposures and inherited susceptibility contributed to the risk of NPC.

Gene-smoking interactions identify several novel blood pressure loci in the Framingham Heart Study

BACKGROUND

Cardiovascular diseases are among the most significant health problems in the United States. Blood pressure (BP) variability has a genetic component, and most of the genetic variance remains to be identified. One promising strategy for gene discovery is genome-wide analysis of interactions between single nucleotide polymorphisms (SNPs) and environmental factors related to cardiovascular diseases.

METHODS

We investigated SNP-smoking interaction effects on BP in genome-wide data in 6,889 participants from the Framingham Heart Study. We performed the standard 1 degree of freedom (df) test of the interaction effect and the joint 2 df test of main and interaction effects. Three smoking measures were used: cigarettes per day (CPD), pack years of smoking, and smoking status.

RESULTS

We identified 7 significant and 21 suggestive BP loci. Identified through the joint 2 df test, significant SBP loci include: rs12149862 (P = 3.65×10(-9)) in CYB5B, rs2268365 (P = 4.85×10(-8)) in LRP2, rs133980 (P = 1.71×10(-8) with CPD and P = 1.07×10(-8) with pack-years) near MN1, and rs12634933 (P = 4.05×10(-8)) in MECOM. Through 1 df interaction analysis, 1 suggestive SBP locus at SNP rs8010717 near NRXN3 was identified using all 3 smoking measures (P = 3.27×10(-7) with CPD, P = 1.03×10(-7) with pack-years, and P = 1.19×10(-7) with smoking status).

CONCLUSIONS

Several of these BP loci are biologically plausible, providing physiological connection to BP regulation. Our study demonstrates that SNP-smoking interactions can enhance gene discovery and provide insight into novel pathways and mechanisms regulating BP.

Recent evidence on alcohol and cancer epidemiology

This review presents an overview of the impact of alcohol consumption on cancer risk. Results from the 2009 International Agency for Research on Cancer monograph as well as the most recent meta-analyses and epidemiological studies are considered. Alcohol consumption is one of the most important known risk factors for human cancer and potentially one of the most avoidable factors, but it is increasing worldwide. Ethanol in alcoholic beverages is carcinogenic to humans and causes several cancers (oral cavity, pharynx, larynx, esophagus, colorectum, liver and female breast). Cumulative lifetime consumption, frequency and drinking pattern appear to play a role in risk characterization. While the role of heavy drinking has been long recognized, new evidence suggests that light consumption (up to one drink/day) is also associated with adverse effects. In addition, some genetic polymorphisms interact with alcohol metabolism and may modify its impact.

Choline and betaine intakes are associated with reduced risk of nasopharyngeal carcinoma in adults: a case-control study

Background:

Intakes of choline and betaine have been inversely related to the risk of various neoplasms, but scant data exist on nasopharyngeal carcinoma (NPC). We examined the association between consumption of choline and betaine and risk of NPC.

Methods:

We conducted a case–control study with 600 incident NPC patients and 600 controls 1 : 1 matched by age, sex and household type in Guangdong, China. Dietary intake was assessed by a food frequency questionnaire through face-to-face interview.

Results:

Intakes of total choline, betaine and choline+betaine were inversely related to NPC after adjustment for various lifestyle and dietary factors (all P-trend <0.001). Adjusted odds ratios (95% CI) for quartile 4 (vs quartile 1) were 0.42 (0.29, 0.61) for total choline, 0.50 (0.35, 0.72) for betaine and 0.44 (0.30, 0.64) for betaine+total choline. Regarding various sources of choline, lower NPC risk was associated with greater intakes of choline from phosphatidylcholine, free choline, glycerophosphocholine and phosphocholine, but not sphingomyelin.

Conclusion:

These findings are consistent with a beneficial effect of choline and betaine intakes on carcinogenesis.

Smoking is a poor prognostic factor for male nasopharyngeal carcinoma treated with radiotherapy

BACKGROUND AND PURPOSE

To evaluate the effect of smoking on prognosis of male nasopharyngeal carcinoma by comparing the treatment outcomes between smokers and non-smokers.

MATERIALS AND METHODS

A total of 2450 nasopharyngeal carcinoma patients were enrolled, including 1865 male patients. Matching was performed between smokers and non-smokers in male patients according to age, UICC clinical stage, T stage, N stage and treatment. Survival outcomes were compared using Kaplan-Meier analysis and Cox regression. Smoking index was calculated by multiplying cigarette packs per day and smoked time (year).

RESULTS

In male patients, smokers had significantly lower 5-year overall survival (70.1% vs. 77.5%, P<0.001) and locoregional recurrent free survival (76.8% vs.82.4%, P = 0.002) compared with non-smokers. Matched-pair analysis showed that smokers kept a high risk of death compared with non-smokers (HR = 2.316, P<0.001). High degree of smoking index (>15 pack-years) had a poor effect on overall survival (HR = 1.225, P = 0.016). When smoking index was more than 45 and 60 pack-years, the risk for death increased to 1.498 and 1.899 fold compared with non-smokers (P = 0.040, 0.001), respectively.

CONCLUSIONS

Smoking was a poor prognostic factor for male nasopharyngeal carcinoma. The heavier the patients smoked, the poorer prognosis they suffered.

Quantitative association of tobacco smoking with the risk of nasopharyngeal carcinoma: a comprehensive meta-analysis of studies conducted between 1979 and 2011

Over the years, many studies have attempted to establish a link between tobacco smoking and an increased risk of nasopharyngeal carcinoma (NPC), but their results have been inconsistent. To clarify this link, we first conducted a comprehensive meta-analysis to integrate the findings of epidemiologic studies from the last half-century. The methodology used for this study followed the checklist proposed by the Meta-analysis of Observational Studies in Epidemiology (MOOSE) Group. Pooled risk estimates were generated using a random-effects model. Twenty-eight case-control studies and 4 cohort studies involving a total of 10,274 NPC cases and 415,266 comparison subjects were included. A substantial effect of smoking on the risk of NPC was identified in this study. The results showed that ever smokers had a 60% greater risk of developing the disease than never smokers (95% confidence interval: 1.38, 1.87); this was a robust dose-dependent association. More importantly, stronger associations were observed in low-risk populations and among persons with the predominant histological type of differentiated NPC than in high-risk populations and persons with an undifferentiated type; the odds ratios were 1.76 and 2.20, respectively, versus 1.29 and 1.27. In this comprehensive meta-analysis, well-established statistical evidence was provided about the role of tobacco smoking in the etiology of NPC.

Secular trends of salted fish consumption and nasopharyngeal carcinoma: a multi-jurisdiction ecological study in 8 regions from 3 continents

BACKGROUND

Despite salted fish being a classical risk factor of Nasopharyngeal Carcinoma (NPC), whether secular trends in salted fish consumption worldwide accounted for changes in NPC rates were unknown. The relationship between vegetable and cigarette consumption to NPC risk worldwide were also largely uncertain. We investigated the longitudinal trends in standardised NPC incidence/mortality rates across 8 regions and their associations with secular trends in salted fish, vegetable and tobacco consumptions.

METHODS

Age standardised mortality rate (ASMR) and age standardised incidence rate (ASIR) of NPC were obtained from the WHO cancer mortality database and Hong Kong Cancer Registry. Per capita consumption of salted fish, tobacco and vegetables in Hong Kong and 7 countries (China, Finland, Japan, Portugal, Singapore, United Kingdom and United States) were obtained from the Food and Agriculture Organization of the United Nation (FAO) and Hong Kong Trade and Census Statistics. Pearson correlation and multivariate analysis were performed to examine both crude and adjusted associations.

RESULTS

There were markedly decreasing trends of NPC ASIR and ASMR in Hong Kong over the past three decades, which were correlated with corresponding secular changes in salted fish consumption per capita (Pearson r for 10 cumulative years : ASIR = 0.729 (male), 0.674 (female); ASMR = 0.943 (male), 0.622 (female), all p < 0.05 except for female ASMR). However such associations no longer correlated with adjustments for decreasing tobacco and increasing vegetable consumption per capita (Pearson r for 10 cumulative years: ASIR = 2.007 (male), 0.339 (female), ASMR = 0.289 (male), 1.992 (female), all p > 0.05). However, there were no clear or consistent patterns in relations between NPC ASIR and ASMR with salted fish consumption across 7 regions in 3 continents.

CONCLUSIONS

Our results do not support the notion that changes in salted fish consumption had played an important role in explaining secular trends of NPC rates in Hong Kong and worldwide. Further studies should explore other lifestyle and genetic factors. However, our findings do support the potentially protective effects of vegetable consumption against NPC.

An epidemiological and molecular study of the relationship between smoking, risk of nasopharyngeal carcinoma, and Epstein-Barr virus activation

BACKGROUND

Elevated levels of antibodies against antigens in the Epstein-Barr virus (EBV) lytic phase are important predictive markers for nasopharyngeal carcinoma (NPC) risk. Several lifestyle factors, including smoking, have also been associated with NPC risk. We hypothesized that some specific lifestyle factors induce transformation of EBV from the latent to the lytic stage and contribute to NPC occurrence.

METHODS

We conducted a case-control study using data from male case patients (n = 1316) and control subjects (n = 1571) living in Guangdong Province, an area in China at high risk for NPC, to study potential NPC risk factors and EBV inducers. Two independent healthy male populations from a second high-risk area (n = 1657) and a low-risk area (n = 1961) were also included in the analysis of potential EBV inducers using logistic regression models. In vitro assays were performed to investigate the effect of cigarette smoke extract on EBV activation in two EBV-positive cell lines. All statistical tests were two-sided.

RESULTS

Smoking was associated with an increased risk of NPC among the Guangdong participants with 20-40 and 40 or more pack-years vs never smokers (OR = 1.52, 95% CI = 1.22 to 1.88 and OR = 1.76, 95% CI = 1.34 to 2.32, respectively; P (trend) < .001). Smoking was the only factor linked to EBV seropositivity among the expanded control group and the independent low-risk population. In vitro experiments showed that cigarette smoke extract promoted EBV replication, induced the expression of the immediate-early transcriptional activators Zta and Rta, and increased transcriptional expression levels of BFRF3 and gp350 in the lytic phase.

CONCLUSION

Smoking is not only associated with NPC risk in individuals from China but is also associated with EBV seropositivity in healthy males and is involved in EBV activation.

Pretreatment lifestyle behaviors as survival predictors for patients with nasopharyngeal carcinoma

BACKGROUND

Lifestyle behaviors have been widely reported to influence the survival of patients with head and neck cancer. However, the relationship between pretreatment lifestyle behaviors and survival among patients with nasopharyngeal carcinoma (NPC) is unclear.

METHODS

A prospective cohort study was designed to determine the relationship between lifestyle behaviors and survival in 1,533 NPC patients recruited from October 2005 to October 2007. Pretreatment lifestyle behaviors (such as body-mass index [BMI], smoking, alcohol, diet) of the patients were investigated. Univariate and multivariate proportional-hazards models were used to assess the impact of lifestyle behaviors on patient survival.

RESULTS

Smoking was a predictor of survival; both current smokers (hazard ratio [HR] = 1.88; 95% CI, 1.33 to 2.65) and heavy smokers (≥ 25 Pack-years; HR = 1.84; 95% CI, 1.30 to 2.60) showed associations with poor survival. Higher BMI was significantly associated with a lower risk of death (P(trend) = 0.002). Compared with under/normal-weight patients (BMI less than 22.99 kg/m(2)), the multivariate HR for survival was 0.66 (95% CI, 0.48 to 0.90) and 0.47 (95% CI, 0.23 to 0.97) for overweight and obese patients, respectively. No alcohol intake and high fruit intake were associated with favorable survival in the univariate analysis but lost significance in the multivariate model.

CONCLUSION

Our findings indicate that pretreatment lifestyle behaviors, especially smoking status and BMI, as easily available data, provide prognostic value for survival in NPC patients.

Non-viral environmental risk factors for nasopharyngeal carcinoma: a systematic review

This review aims to systematically summarize the epidemiological studies on nasopharyngeal carcinoma (NPC) conducted over the past half century, covering descriptive epidemiological studies and reports on non-viral risk factors. Multiple lines of epidemiologic evidence for established risk factors are systematically presented in comprehensive tables. The potential interactions among environmental factors and genetic components, and also the impacts of parallel sequencing technology on the aetiology of NPC are discussed. Finally, we propose a modified model for the pathogenesis of nasopharyngeal carcinoma based on the current knowledge.

Tobacco smoking, alcohol drinking, and the risk of different histological types of nasopharyngeal cancer in a low-risk population

Nasopharyngeal carcinoma (NPC) is rare in western Countries. Tobacco smoking is a well-recognised risk factor, whereas the role of alcohol drinking is still in debate. We conducted a hospital-based case-control study in Italy on 150, histologically-confirmed, NPC cases of Caucasian ethnicity, aged 18-76years, including 118 undifferentiated NPCs and 22 differentiated squamous-cell NPC. Controls were 450 Caucasian cancer-free patients admitted to general hospitals for acute conditions. Cases and controls were matched according to sex, age, and place of residence. Logistic regression was used to estimate odds ratios (OR) and the corresponding 95% confidence intervals (CI) while adjusting for known confounders. No significant association emerged between tobacco smoking and all NPCs (OR for current vs. never smokers=1.52; 95% CI: 0.89-2.60). Conversely, for differentiated NPC only, statistically significant elevated OR were associated with increasing smoking intensity (OR for ⩾15cigarettes/day=5.40; 95% CI: 1.34-21.76) and duration of the habit (OR for ⩾32years=4.48; 95% CI: 1.11-18.04). Although alcohol drinking was not, per se, significantly associated to NPC risk, the combination of tobacco smoking and alcohol drinking accounted for 57% of differentiated NPCs, whereas it accounted for only 14% of undifferentiated carcinomas. Our findings suggest that, in western populations, NPC includes two separate entities: the differentiated NPC, associated with tobacco smoking like other cancers of head and neck, and the undifferentiated NPC, upon which tobacco smoking has little or no influence.

Estimation of cancer incidence and mortality attributable to alcohol drinking in China

BACKGROUND

Cancer constitutes a serious burden of disease worldwide and has become the second leading cause of death in China. Alcohol consumption is causally associated with the increased risk of certain cancers. Due to the current lack of data and the imperative need to guide policymakers on issues of cancer prevention and control, we aim to estimate the role of alcohol on the cancer burden in China in 2005.

METHODS

We calculated the proportion of cancers attributable to alcohol use to estimate the burden of alcohol-related cancer. The population attributable fraction was calculated based on the assumption of no alcohol drinking. Data on alcohol drinking prevalence were from two large-scale national surveys of representative samples of the Chinese population. Data on relative risk were obtained from meta-analyses and large-scale studies.

RESULTS

We found that a total of 78,881 cancer deaths were attributable to alcohol drinking in China in 2005, representing 4.40% of all cancers (6.69% in men, 0.42% in women). The corresponding figure for cancer incidence was 93,596 cases (3.63% of all cancer cases). Liver cancer was the main alcohol-related cancer, contributing more than 60% of alcohol-related cancers.

CONCLUSIONS

Particular attention needs to be paid to the harm of alcohol as well as its potential benefits when making public health recommendations on alcohol drinking.

Association of the interleukin-2 polymorphisms with interleukin-2 serum levels and risk of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China. In addition to environmental factors such as Epstein-Barr virus infection and chemical carcinogen exposure, genetic susceptibility has been reported to play a key role in the development of this disease. Interleukin-2 (IL-2) is an immunoregulatory cytokine produced by T cells and plays an important role in antitumor immunity. Variations in the DNA sequence of the IL-2 gene may lead to altered cytokine production and/or activity, and thus modulate an individual's susceptibility to NPC. To test this hypothesis, we investigated whether IL-2 gene polymorphisms and its serum levels are associated with NPC in a Chinese population. We analyzed single-nucleotide polymorphisms of IL-2 gene -330 T/G and +114 T/G in 180 patients with NPC and 200 age- and sex-matched controls, using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing methods, and serum IL-2 levels were measured by enzyme-linked immunosorbent assay. Serum IL-2 levels were decreased in patients with NPC compared with controls (p < 0.01). There were significant differences in the genotype and allele frequencies of IL-2 gene -330 T/G polymorphism between the group of patients with NPC and the control group (p < 0.05). Moreover, genotypes carrying the IL-2 -330 G variant allele were associated with decreased serum IL-2 levels compared with the homozygous wild-type genotype in patients with NPC. Carrying the IL-2 -330 G variant allele was associated with a decreased ability to produce IL-2, which may contribute to NPC susceptibility.

The progress on genetic analysis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is one of the most common cancers in Southeast Asia. Both genetic and environmental factors contribute to the tumorigenesis of NPC, most notably the consumption of certain salted food items and Epstein-Barr virus infection. This review will focus on the current progress of the genetic analysis of NPC (genetic susceptibilities and somatic alterations). We will review the current advances in genomic technologies and their shaping of the future direction of NPC research.

Cannabis, tobacco and domestic fumes intake are associated with nasopharyngeal carcinoma in North Africa

Background:

The lifestyle risk factors for nasopharyngeal carcinoma (NPC) in North Africa are not known.

Methods:

From 2002 to 2005, we interviewed 636 patients and 615 controls from Algeria, Morocco and Tunisia, frequency-matched by centre, age, sex, and childhood household type (urban/rural). Conditional logistic regression was used to evaluate the association of lifestyles with NPC risk, controlling for socioeconomic status and dietary risk factors.

Results:

Cigarette smoking and snuff (tobacco powder with additives) intake were significantly associated with differentiated NPC but not with undifferentiated carcinoma (UCNT), which is the major histological type of NPC in these populations. As demonstrated by a stratified permutation test and by conditional logistic regression, marijuana smoking significantly elevated NPC risk independently of cigarette smoking, suggesting dissimilar carcinogenic mechanisms between cannabis and tobacco. Domestic cooking fumes intake by using kanoun (compact charcoal oven) during childhood increased NPC risk, whereas exposure during adulthood had less effect. Neither alcohol nor shisha (water pipe) was associated with risk.

Conclusion:

Tobacco, cannabis and domestic cooking fumes intake are risk factors for NPC in western North Africa.

Evaluation of nonviral risk factors for nasopharyngeal carcinoma in a high-risk population of Southern China

To understand the role of environmental and genetic influences on nasopharyngeal carcinoma (NPC) in populations at high risk of NPC, we have performed a case-control study in Guangxi Province of Southern China in 2004-2005. NPC cases (n = 1,049) were compared with 785 NPC-free matched controls who were seropositive for IgA antibodies (IgA) to Epstein-Barr virus (EBV) capsid antigen (VCA)-a predictive marker for NPC in Chinese populations. A questionnaire was used to capture exposure and NPC family history data. Risk factors associated with NPC in a multivariant analysis model were the following: (i) a first, second or third degree relative with NPC [attributable risk (AR)= 6%, odds ratio (OR) = 3.1, 95% confidence interval (CI) = 2.0-4.9, p < 0.001]; (ii) consumption of salted fish 3 or more than 3 times per month (AR = 3%, OR = 1.9, 95% CI = 1.1-3.5, p = 0.035); (iii) exposure to domestic wood cooking fires for more than 10 years (AR = 69%, OR = 5.8, 95% CI = 2.5-13.6, p < 0.001); and (iv) exposure to occupational solvents for 10 or less years (AR = 4%, OR = 2.6, 95% CI = 1.4-4.8, p = 0.002). Consumption of preserved meats or a history of tobacco smoking were not associated with NPC (p > 0.05). We also assessed the contribution of EBV/IgA/VCA antibody serostatus to NPC risk-32.2% of NPC can be explained by IgA+ status. However, family history and environmental risk factors cumulatively explained only 2.7% of NPC development in NPC high risk population. These findings should have important public health implications for NPC risk reduction in endemic regions.

Alcohol consumption and the risk of nasopharyngeal carcinoma: a systematic review

The evidence concerning the influence of alcohol drinking on the risk of nasopharyngeal carcinoma (NPC) has yielded intriguing findings but has lacked a clear-cut interpretation due to inconsistencies. To unify this body of evidence, we performed a systematic review. With funding and using a protocol developed by the World Cancer Research Fund (WCRF), 15 bibliographic databases were searched for epidemiological studies that reported a measure of association between alcoholic beverage consumption and NPC. Pooled odds ratios (ORs) for highest-vs.-lowest categories of total alcohol intake was obtained by using an inverse-variance weighted random-effects model. A dose-response trend was examined in models using generalized least square estimation. The search identified 14 case-control studies from 5 countries. For total alcohol intake, the pooled ORs in a comparison of the highest to the lowest category was 1.33 (95% CI: = 1.09-1.62) in 11 studies. Data from 6 studies indicated a J-shape dose-response trend, with NPC risk decreasing with up to 15 drinks/wk and increasing with higher intake. Fewer data were available to assess the associations between NPC and intake of beer, wine, and spirits. The potential J-shaped dose-response trend suggests a reduced risk of NPC related to the light alcohol drinking, an observation that warrants further study. Considered in total, the quantitative summaries of the case-control evidence suggest that heavy alcohol consumption is associated with an increased risk of NPC.