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Background: Vitamin C insufficiency occurs across many countries and has been hypothesised to increase risk of various diseases. Few prospective studies with measured circulating vitamin C have related deficiency to disease mortality, particularly in low-income and middle-income countries., Methods: We randomly selected 948 subjects (473 males and 475 females) aged 53-84 years from a Chinese cohort and measured meta-phosphoric acid-preserved vitamin C concentrations in plasma samples collected in 1999-2000. A total of 551 deaths were accrued from sample collection through 2016, including 141 from cancer, 170 from stroke and 174 from heart diseases. Vitamin C was analysed using season-specific quartiles, as a continuous variable and as a dichotomous variable based on sufficiency status (normal >28 µmol/L vs low ≤28 µmol/L). HRs and 95% CIs were estimated using Cox proportional hazards models., Results: We found significant inverse associations between higher plasma vitamin C concentrations and total mortality in quartile (HR Q4 vs Q1 0.75, 95% CI 0.59 to 0.95), continuous (HR q20umol/L 0.90, 95% CI 0.82 to 0.99) and dichotomous analyses (HR normal-vs-low 0.77, 95% CI 0.63 to 0.95). We observed significant lower risks of heart disease (p trend-by-quantile =0.03) and cancer deaths (p global-across-quantile =0.04) for higher vitamin C, whereas the association was attenuated for stroke in adjusted models. Similar inverse associations were found when comparing normal versus low vitamin C for heart disease (HR normal-vs-low 0.62, 95% CI 0.42 to 0.89)., Conclusion: In this long-term prospective Chinese cohort study, higher plasma vitamin C concentration was associated with lower total mortality, heart disease mortality and cancer mortality. Our results corroborate the importance of adequate vitamin C to human health., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Colorectal cancers are the third most common cancers in women and men in the USA. While dietary and lifestyle factors such as Western diet, physical inactivity and obesity have been linked to an increased risk of this malignancy, the mechanisms for these associations are unclear. GI hormones, including ghrelin, are involved in energy balance by mediating appetite and metabolism; however, the association between ghrelin and colorectal cancer has not been studied., Methods: We conducted a case-control study nested within the all-male Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish smokers (aged 50-69 years) to examine serum ghrelin concentration and colorectal cancer risk. Data from 284 colon and 239 rectal cancers and 523 controls (matched on age, date of blood draw and serum availability) were analysed. ORs and 95% CIs were calculated using multivariable (conditional) logistic regression., Results: Overall, low-serum ghrelin was significantly associated with increased risk of colorectal cancer (Q1 vs Q4: OR:1.57, 95% CI 1.05 to 2.34). For individuals developing tumours within 10 years of blood draw, those in the lowest quartile of serum ghrelin concentrations were statistically significantly more likely to develop colorectal cancers than those with higher serum ghrelin concentrations (OR: 10.86, 95% CI 5.01 to 23.55). However, for individuals with tumours developing more than 20 years after blood draw, low-serum ghrelin concentrations were associated with a decreased risk of colorectal cancer relative to those with the highest serum ghrelin concentrations (OR: 0.26, 95% CI 0.11 to 0.64)., Conclusion: Low-serum ghrelin was associated with an increased colorectal cancer risk within 10 years of blood draw with a decreased risk for developing colorectal cancer more than 20 years after blood draw. These results suggest that ghrelin concentrations may vary across the carcinogenic process., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: A history of periodontal disease and the presence of circulating antibodies to selected oral pathogens have been associated with increased risk of pancreatic cancer; however, direct relationships of oral microbes with pancreatic cancer have not been evaluated in prospective studies. We examine the relationship of oral microbiota with subsequent risk of pancreatic cancer in a large nested case-control study., Design: We selected 361 incident adenocarcinoma of pancreas and 371 matched controls from two prospective cohort studies, the American Cancer Society Cancer Prevention Study II and the National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. From pre-diagnostic oral wash samples, we characterised the composition of the oral microbiota using bacterial 16S ribosomal RNA (16S rRNA) gene sequencing. The associations between oral microbiota and risk of pancreatic cancer, controlling for the random effect of cohorts and other covariates, were examined using traditional and L1-penalised least absolute shrinkage and selection operator logistic regression., Results: Carriage of oral pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans , were associated with higher risk of pancreatic cancer (adjusted OR for presence vs absence=1.60 and 95% CI 1.15 to 2.22; OR=2.20 and 95% CI 1.16 to 4.18, respectively). Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk (OR per per cent increase of relative abundance=0.94 and 95% CI 0.89 to 0.99; OR=0.87 and 95% CI 0.79 to 0.95, respectively). Risks related to these phylotypes remained after exclusion of cases that developed within 2 years of sample collection, reducing the likelihood of reverse causation in this prospective study., Conclusions: This study provides supportive evidence that oral microbiota may play a role in the aetiology of pancreatic cancer., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Background: Recent studies have suggested that opium use may increase mortality from cancer and cardiovascular diseases. However, no comprehensive study of opium use and mortality from respiratory diseases has been published. We aimed to study the association between opium use and mortality from respiratory disease using prospectively collected data., Methods: We used data from the Golestan Cohort Study, a prospective cohort study in northeastern Iran, with detailed, validated data on opium use and several other exposures. A total of 50 045 adults were enrolled from 2004 to 2008, and followed annually until June 2015, with a follow-up success rate of 99%. We used Cox proportional hazard regression models to evaluate the association between opium use and outcomes of interest., Results: During the follow-up period, 331 deaths from respiratory disease were reported (85 due to respiratory malignancies and 246 due to non-malignant aetiologies). Opium use was associated with an increased risk of death from any respiratory disease (adjusted HR 95% CI 3.13 (2.42 to 4.04)). The association was dose-dependent with a HR of 3.84 (2.61 to 5.67) for the highest quintile of cumulative opium use versus never use (P trend <0.001). The HRs (95% CI) for the associations between opium use and malignant and non-malignant causes of respiratory mortality were 1.96 (1.18 to 3.25) and 3.71 (2.76 to 4.96), respectively., Conclusions: Long-term opium use is associated with increased mortality from both malignant and non-malignant respiratory diseases., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: Although several genome-wide association studies (GWAS) of non-cardia gastric cancer have been published, more novel association signals could be exploited by combining individual studies together, which will further elucidate the genetic susceptibility of non-cardia gastric cancer., Design: We conducted a meta-analysis of two published Chinese GWAS studies (2031 non-cardia gastric cancer cases and 4970 cancer-free controls) and followed by genotyping of additional 3564 cases and 4637 controls in two stages., Results: The overall meta-analysis revealed two new association signals. The first was a novel locus at 5q14.3 and marked by rs7712641 (per-allele OR=0.84, 95% CI 0.80 to 0.88; p=1.21×10 -11 ). This single-nucleotide polymorphism (SNP) marker maps to the intron of the long non-coding RNA, lnc-POLR3G-4 ( XLOC&#95;004464 ), which we observed has lower expression in non-cardia gastric tumour compared with matched normal tissue (P wilcoxon signed-rank =7.20×10 -4 ). We also identified a new signal at the 1q22 locus, rs80142782 (per-allele OR=0.62; 95% CI 0.56 to 0.69; p=1.71×10 -19 ), which was independent of the previously reported SNP at the same locus, rs4072037 (per-allele OR=0.74; 95% CI 0.69 to 0.79; p=6.28×10 -17 ). Analysis of the new SNP conditioned on the known SNP showed that the new SNP remained genome-wide significant (P conditional =3.47×10 -8 ). Interestingly, rs80142782 has a minor allele frequency of 0.05 in East Asians but is monomorphic in both European and African populations., Conclusion: These findings add new evidence for inherited genetic susceptibility to non-cardia gastric cancer and provide further clues to its aetiology in the Han Chinese population., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: Genome-wide association studies (GWAS) of gastric cancer have reported differences in single-nucleotide polymorphism (SNP) associations for tumour subtypes, particularly when divided by location into the gastric cardia versus the non-cardia., Design: Here we present results for a GWAS using 2350 East Asian gastric cancer cases divided as 1189 gastric cardia and 1027 gastric non-cardia cases and 2708 controls. We also included up to 3042 cardia cases, 4359 non-cardia cases and 7548 controls for replication from two Chinese studies and one Korean study. From the GWAS, we selected 12 top SNPs for each gastric cancer subtype, 4 top SNPs for total gastric cancer and 1 SNP in MUC1 for replication testing., Results: We observed genome-wide significant associations for rs10074991 in PRKAA1 at 5p13.1 for cardia (p=7.36×10(-12)) and non-cardia cancers (p=2.42×10(-23)) with per allele OR (95% CI) for the combined endpoint of 0.80 (0.77 to 0.83). At 6p21.1, rs2294693 near UNC5CL was significantly associated with gastric non-cardia cancer risk (p=2.50×10(-8)), with OR (95% CI) of 1.18 (1.12 to 1.26), but there was only a nominal association for cardia cancer (p=1.47×10(-2)). We also confirmed a previously reported association for rs4072037 in MUC1 with p=6.59×10(-8) for total gastric cancer and similar estimates for cardia and non-cardia cancers. Three SNPs in PSCA previously reported to be associated with gastric non-cardia cancer showed no apparent association for cardia cancer., Conclusions: Our results suggest that associations for SNPs with gastric cancer show some different results by tumour location in the stomach., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Background: Gastric atrophy, as determined by a low serum pepsinogen I:II ratio, may be associated with an increased risk of oesophageal squamous cell carcinoma (OSCC). Ghrelin, a hormone which, is also produced in the gastric fundic glands may be a marker of gastric atrophy, but its association with OSCC is not known., Methods: To examine the relationship between baseline serum ghrelin concentration and subsequent risk of OSCC, the authors conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study. 82 cases of OSCC were matched (1:1) by age and date of blood draw to controls from the ATBC study. Serum ghrelin was measured by radioimmunoassay. ORs and 95% CIs were calculated using conditional logistic regression with adjustment for potential confounders., Results: For individuals in the lowest quartile of serum ghrelin, compared to those in the highest, the multivariate OR of subsequent OSCC was 6.83 (95% CI 1.46 to 31.84). These associations were dose dependent (p value for trend =0.005 for both), and independent of the effects of low pepsinogen I:II ratio and Helicobacter pylori infection. The significance of these associations remained even for individuals developing OSCC up to 10 years after baseline ghrelin measurement, although they become attenuated after 10 years., Conclusion: Lower baseline concentrations of serum ghrelin were associated with an increase in risk of OSCC. Further studies are needed to confirm this finding in other populations and to explore the role of ghrelin in the aetiology of OSCC.

Objective: The incidence of oesophageal adenocarcinoma (EAC) has increased rapidly over the past 40 years and accumulating evidence suggests that obesity, as measured by body mass index (BMI), is a major risk factor. It remains unclear whether abdominal obesity is associated with EAC and gastric adenocarcinoma., Design: Cox proportional hazards regression was used to examine associations between overall and abdominal obesity with EAC and gastric adenocarcinoma among 218 854 participants in the prospective NIH-AARP cohort., Results: 253 incident EAC, 191 gastric cardia adenocarcinomas and 125 gastric non-cardia adenocarcinomas accrued to the cohort. Overall obesity (BMI) was positively associated with EAC and gastric cardia adenocarcinoma risk (highest (≥35 kg/m(2)) vs referent (18.5-<25 kg/m(2)); HR 2.11, 95% CI 1.09 to 4.09 and HR 3.67, 95% CI 2.00 to 6.71, respectively). Waist circumference was also positively associated with EAC and gastric cardia adenocarcinoma risk (highest vs referent; HR 2.01, 95% CI 1.35 to 3.00 and HR 2.22, 95% CI 1.43 to 3.47, respectively), whereas waist-to-hip ratio (WHR) was positively associated with EAC risk only (highest vs referent; HR 1.81, 95% CI 1.24 to 2.64) and persisted in patients with normal BMI (18.5-<25 kg/m(2)). Mutual adjustment of WHR and BMI attenuated both, but did not eliminate the positive associations for either with risk of EAC. In contrast, the majority of the anthropometric variables were not associated with adenocarcinomas of the gastric non-cardia., Conclusion: Overall obesity was associated with a higher risk of EAC and gastric cardia adenocarcinoma, whereas abdominal obesity was found to be associated with increased EAC risk; even in people with normal BMI.

Background and Aims: Alcohol intake is a strong and well established risk factor for oesophageal squamous cell carcinoma (OSCC), but the association with oesophageal adenocarcinoma (OA) or adjacent tumours of the oesophagogastric junction (OGJA), remains unclear. Therefore, the association of alcohol intake with OSCC, OA, and OGJA was determined in nine case-control studies and two cohort studies of the Barrett's Esophagus and Esophageal Adenocarcinoma Consortium (BEACON)., Materials and Methods: Information was collected on alcohol intake, age, sex, education, body mass index, gastro-oesophageal reflux, and tobacco smoking from each study. Along with 10,854 controls, 1821 OA, and 1837 OGJA, seven studies also collected OSCC cases (n=1016). Study specific ORs and 95% CIs were calculated from multivariate adjusted logistic regression models for alcohol intake in categories compared to non-drinkers. Summary risk estimates were obtained by random effects models. Results No increase was observed in the risk of OA or OGJA for increasing levels of any of the alcohol intake measures examined. ORs for the highest frequency category (≥ 7 drinks per day) were 0.97 (95% CI 0.68 to 1.36) for OA and 0.77 (95% CI = 0.54 to 1.10) for OGJA. Suggestive findings linked moderate intake (eg, 0.5 to <1 drink per day) to decreased risk of OA (OR 0.63, 95% CI 0.41 to 0.99) and OGJA (OR 0.78, 95% CI 0.62 to 0.99). In contrast, alcohol intake was strongly associated with increased risk of OSCC (OR for ≥ 7 drinks per day 9.62, 95% CI 4.26 to 21.71)., Conclusions: In contrast to OSCC, higher alcohol consumption was not associated with increased risk of either OA or OGJA. The apparent inverse association observed with moderate alcohol intake should be evaluated in future prospective studies.

Background: Cancers of the upper gastrointestinal tract remain a significant cause of morbidity and mortality. Cysteine, known to be involved in a myriad of immuno-modulatory, anti-oxidant, and anti-carcinogenic pathways, has not been investigated in the aetiology of oesophageal or gastric cancers. To examine the relationship between serum cysteine concentration and risk of these cancers we conducted a nested case-cohort study within the General Population Nutrition Intervention Trial in Linxian, China., Methods: 498 oesophageal squamous cell carcinomas (OSCCs) and 255 gastric cardia adenocarcinomas (GCAs) were matched by age and sex to 947 individuals from the wider cohort. We calculated HRs and 95% CIs using the case-cohort estimator for the Cox proportional hazards models, stratified on age and sex, with adjustment for potential confounders., Results: Higher concentrations of serum cysteine were significantly associated with a lower risk of both OSCC and GCA. For those in the highest quartile of serum cysteine, compared to those in the lowest, the multivariate HRs were 0.70 for OSCC (95% CI 0.51 to 0.98) and 0.59 for GCA (95% CI 0.38 to 0.91). These associations were dose dependent (p for trend=0.006 and 0.008, respectively). These inverse associations were not significantly modified by other risk factors, with the exception of age, where a stronger association was noted among persons in the older age strata., Conclusion: Higher serum concentrations of cysteine were associated with a significantly reduced risk of OSCC and GCA. Cysteine should be further investigated for its potential as a chemopreventive agent for upper gastrointestinal cancers.

Objective: To evaluate the association between polycyclic aromatic hydrocarbon (PAH) exposure in oesophageal epithelial tissue and oesophageal squamous cell carcinoma (ESCC) case status in an ESCC case-control study in a high-risk population in north-eastern Iran., Methods: Tissue microarrays (TMAs) of non-tumoral oesophageal biopsies from patients with biopsy-proven ESCC and gastrointestinal clinic patients with no endoscopic or biopsy evidence of ESCC (control subjects) in a rural region in north-eastern Iran were immunohistochemically stained. Immunohistochemistry was performed using monoclonal antibodies 8E11 and 5D11 raised against benzo[a]pyrene (B[a]P) diol epoxide (BPDE)-I-modified guanosine and BPDE-I-modified DNA, respectively. Staining intensity was quantified by image analysis and the average staining in three replicates was calculated. The main outcome measure was adjusted ORs with 95% CIs for the association between antibody staining intensity and ESCC case status., Results: Cultured ESCC cells exposed to B[a]P in vitro showed dose-dependent staining with 8E11 but not with 5D11. With 8E11, sufficient epithelial tissue was available in the TMA cores to analyse 91 cases and 103 controls. Compared with the lowest quintile of 8E11 staining in the controls, adjusted ORs for the 2nd to 5th quintiles were 2.42, 5.77, 11.3 and 26.6 (95% CI 5.21 to 135), respectively (p for trend <0.001). With 5D11, 89 cases and 101 controls were analysed. No association between staining and case status was observed (ORs for the 2nd to 5th quintiles were 1.26, 0.88, 1.06 and 1.63 (95% CI 0.63 to 4.21), p for trend=0.40)., Conclusions: Dramatically higher levels of 8E11 staining were observed in non-tumoral oesophageal epithelium from patients with ESCC than from control subjects. This finding strengthens the evidence for a causal role for PAHs in oesophageal carcinogenesis in north-eastern Iran.

Objective: Low serum pepsinogen I (PGI) and low pepsinogen I/pepsinogen II ratio (PGI/II ratio) are markers of gastric fundic atrophy. We aimed to prospectively test the association between serum PGI/II ratio and risks of gastric non-cardia adenocarcinoma, gastric cardia adenocarcinoma, and oesophageal squamous cell carcinoma (OSCC)., Design: Case-cohort study nested in a prospective cohort with over 15 years of follow-up., Setting: Rural region of the People's Republic of China., Subjects: Men and women aged 40-69 years at study baseline., Main Outcome Measures: Adjusted hazard ratios and 95% confidence intervals for the association between serum PGI/II ratio and cancer risk., Results: Compared to subjects with PGI/II ratio of >4, those with

Background: Gastric cancer incidence rates are consistently lower in women than men in both high and low-risk regions worldwide. Sex hormones, such as progesterone and estrogen, may protect women against gastric cancer., Objective: To investigate the association of menstrual and reproductive factors and gastric cancer risk., Methods: These associations were prospectively investigated in 73 442 Shanghai women. After 419 260 person-years of follow-up, 154 women were diagnosed with gastric cancer. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models adjusted for age, body mass index, education, income, and cigarette use., Results: No associations were observed between gastric cancer risk and age of menarche, number of children, breast feeding, or oral contraceptive use. In contrast, associations were observed with age of menopause (HR 0.80 per five-year increase in menopausal age, 95% CI 0.66-0.97), years of fertility (participants with less than 30 years of fertility were at increased risk compared with those with 30-36 years of fertility, HR 1.90, 95% CI 1.25-2.90), years since menopause (HR 1.26 per five years, 95% CI 1.03-1.53), and intrauterine device use (HR for users 1.61, 95% CI 1.08-2.39)., Conclusions: These results support the hypothesis that female hormones play a protective role in gastric cancer risk.

Background: Stroke is the leading cause of death in Linxian, China. Although there is evidence of DNA damage in experimental stroke, no data exist on DNA repair and stroke in human populations., Aim: To assess the risk of stroke conferred by polymorphisms in the DNA repair genes, XRCC1, XPD23 and APE/ref-1 in a cohort of individuals originally assembled as subjects in two cancer prevention trials in Linxian, China., Methods: The subjects for this prospective study were sampled from a cohort of 4,005 eligible subjects who were alive and cancer free in 1991 and had blood samples available for DNA extraction. Using real-time Taqman analyses, all incident cases of stroke (n = 118) that developed from May 1996, and an age- and a sex-stratified random sample (n = 454) drawn from all eligible subjects were genotyped. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% CIs., Results: No association was observed between polymorphisms in APE/ref-1 codon 148 and XRCC16 codon 194, and stroke. Polymorphisms in XRCC110 codon 399 were associated with a significantly reduced risk of stroke (RR 0.59, 95% CI 0.36 to 0.96, p = 0.033), whereas XPD23 codon 312 was associated with a significantly increased risk of stroke (RR 2.18, 95% CI 1.14 to 4.17, p = 0.010)., Conclusions: Polymorphisms in DNA repair genes may be important in the aetiology of stroke. These data should stimulate research on DNA damage and repair in stroke.

Background: Oesophageal squamous cell carcinoma (OSCC) is a common cancer worldwide and has a very high mortality rate. Squamous dysplasia is the precursor lesion for OSCC and it can be seen during routine endoscopy with Lugol's iodine staining. We aimed to examine the risk factors for squamous dysplasia and determine if a risk model could be constructed which would be useful in selecting apparently healthy subjects for endoscopic screening in a high risk population in Linzhou, People's Republic of China., Subjects and Methods: In this cross sectional study, 724 adult volunteers aged 40-65 years were enrolled. All subjects completed a questionnaire regarding potential environmental exposures, received physical and dental examinations, and underwent upper endoscopy with Lugol's iodine staining and biopsy. Subjects were categorised as having or not having histologically proven squamous dysplasia/early cancer. Risk factors for dysplasia were examined using univariate and multivariate logistic regression. The utility of the final multivariate model as a screening tool was assessed using a receiver operating characteristics curve., Results: We found that 230 of 720 subjects (32%) with complete data had prevalent squamous dysplasia. In the final multivariate model, more household members (odds ratio (OR) 1.12/member (95% confidence interval (CI) 0.99, 1.25)), a family history of cancer (OR 1.57 (95% CI 1.13-2.18)), higher systolic blood pressure OR 1.11/10 mm Hg (95% CI 1.03-1.19)), heating the home without a chimney (OR 2.22 (95% CI 1.27-3.86)), and having lost more but not all of your teeth (OR 1.91 for 12-31 teeth lost (95% CI 1.17-3.15)) were associated with higher odds of having dysplasia. Higher household income (OR 0.96/100 RMB (95% CI 0.91-1.00)) was associated with a lower odds of having dysplasia. Although we found several statistically significant associations, the final model had little ability to accurately predict dysplasia status, with maximum simultaneous sensitivity and specificity values of 57% and 54%, respectively., Conclusions: We found that risk factors for dysplasia were similar to those previously identified as risk factors for OSCC in this population. The final model did a poor job of identifying subjects who had squamous dysplasia. Other methods will need to be developed to triage individuals to endoscopy in this high risk population.

Background: Oesophageal squamous cell carcinoma (OSCC) has a very poor prognosis, which is largely due to late diagnosis. Successful early detection strategies will require identification of clinically relevant precursor lesions that can be targets for screening and treatment., Aims: To identify the clinically relevant histological precursors of OSCC., Subjects: A cohort of 682 endoscoped patients from a high risk rural population in Linxian, China., Methods: Subjects were endoscoped and biopsied at baseline and followed for 13.5 years. We estimated the relative risk of developing OSCC for each of the initial histological diagnoses using Cox proportional hazards regression models., Results: A total of 114 (16.7%) patients developed OSCC during the follow up period. After adjusting for potential confounding factors, relative risks (95% confidence intervals) for incidence of this tumour, by initial histological diagnosis, were: normal 1.0 (reference), oesophagitis 0.8 (0.2-3.2), basal cell hyperplasia 1.9 (0.8-4.5), mild dysplasia 2.9 (1.6-5.2), moderate dysplasia 9.8 (5.3-18.3), severe dysplasia 28.3 (15.3-52.3), and carcinoma in situ 34.4 (16.6-71.4)., Conclusions: In this study, squamous dysplasia and carcinoma in situ were the only histological lesions associated with a significantly increased risk of developing OSCC within 13.5 years after endoscopy. There was no evidence that oesophagitis predisposed to this tumour. Increasing grades of dysplasia were strongly associated with increasing risk, indicating that the histological grading was clinically meaningful. The follow up experience of severe dysplasia and carcinoma in situ was equivalent, suggesting that this distinction is not clinically relevant. Documenting these precursor lesions of OSCC should assist in the development of effective prevention, early detection, and treatment strategies for this disease.