Farhad Islami

Carcinogenicity of radiofrequency electromagnetic fields

Robert Baan a, Yann Grosse a, Beatrice Lauby-Secretan a, Fatiha El Ghissassi a, Veronique Bouvard a, Lamia Benbrahim-Tallaa a, Neela Guha a, Farhad Islami a, Laurent Galichet a, Kurt Straif a, on behalf of the WHO International Agency for Research on Cancer Monograph Working Group In May, 2011, 30 scientists from 14 countries met at the International Agency for Research on Cancer (IARC) in Lyon, France, to assess the carcinogenicity of radiofrequency electromagnetic fields (RF-EMF). These assessments will be published as Volume 102 of the IARC Monographs.1

Alcohol drinking and colorectal cancer risk: an overall and dose–response meta-analysis of published studies

BACKGROUND The International Agency for Research on Cancer (IARC) concluded that alcohol consumption is related to colorectal cancer (CRC). However, several issues remain unresolved, including quantification of the association for light (≤1 drink/day) and moderate (2-3 drinks/day) alcohol drinking, investigation of the dose-response relationship, and potential heterogeneity of effects by sex, colorectal site, and geographical region. METHODS Twenty-seven cohort and 34 case-control studies presenting results for at least three categories of alcohol intake were identified from a PubMed search of articles published before May 2010. The summary relative risks (RRs) were estimated by the random effects model. Second-order fractional polynomials and random effects meta-regression models were used for modeling the dose-risk relation. RESULTS The RRs were 1.21 [95% confidence interval (CI) 1.13-1.28] for moderate and 1.52 (95% CI 1.27-1.81) for heavy (≥4 drinks/day) alcohol drinking. The RR for moderate drinkers, compared with non-/occasional drinkers, was stronger for men (RR = 1.24, 95% CI 1.13-1.37) than for women (RR = 1.08, 95% CI 1.03-1.13; P(heterogeneity) = 0.02). For heavy drinkers, the association was stronger in Asian studies (RR = 1.81, 95% CI 1.33-2.46; P(heterogeneity) = 0.04). The dose-risk analysis estimated RRs of 1.07 (95% CI 1.04-1.10), 1.38 (95% CI 1.28-1.50), and 1.82 (95% CI 1.41-2.35) for 10, 50, and 100 g/day of alcohol, respectively. CONCLUSIONS This meta-analysis provides strong evidence for an association between alcohol drinking of >1 drink/day and colorectal cancer risk.

Helicobacter pylori and Esophageal Cancer Risk: A Meta-analysis

We conducted this meta-analysis to examine the association between Helicobacter pylori and esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma. We searched the PubMed database, the ISI database, and the references of the selected articles. Case-control or nested case-control studies were selected if they used serology or endoscopic methods to detect H. pylori in the stomach and if control subjects were not restricted to upper gastrointestinal tract cancer or peptic ulcer disease patients. A total of 19 studies were used for this analysis. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using the DerSimonian-Laird method. Q statistics and I2 statistics were calculated to examine heterogeneity. Subgroup analyses were conducted by CagA status. For EAC, the summary OR (95% CI) was 0.56 (0.46-0.68). There was little heterogeneity among studies (I2 = 15%). Further analysis showed that colonization with CagA-positive strains was inversely associated with EAC risk (OR, 0.41; 95% CI, 0.28-0.62) but colonization with CagA-negative strains was not (OR, 1.08; 95% CI, 0.76-1.53). For esophageal squamous cell carcinoma, the summary OR (95% CI) was 1.10 (0.78-1.55). However, there was substantial heterogeneity among studies (I2 = 73%), with statistically significant associations in both directions. Our results suggest an inverse association between CagA-positive H. pylori colonization and risk of EAC. The prominent decline of H. pylori colonization in the past few decades may be partly responsible for the recent increase in EAC incidence in Western countries.

Alcohol consumption and site-specific cancer risk: a comprehensive dose-response meta-analysis

Background:Alcohol is a risk factor for cancer of the oral cavity, pharynx, oesophagus, colorectum, liver, larynx and female breast, whereas its impact on other cancers remains controversial.Methods:We investigated the effect of alcohol on 23 cancer types through a meta-analytic approach. We used dose–response meta-regression models and investigated potential sources of heterogeneity.Results:A total of 572 studies, including 486 538 cancer cases, were identified. Relative risks (RRs) for heavy drinkers compared with nondrinkers and occasional drinkers were 5.13 for oral and pharyngeal cancer, 4.95 for oesophageal squamous cell carcinoma, 1.44 for colorectal, 2.65 for laryngeal and 1.61 for breast cancer; for those neoplasms there was a clear dose–risk relationship. Heavy drinkers also had a significantly higher risk of cancer of the stomach (RR 1.21), liver (2.07), gallbladder (2.64), pancreas (1.19) and lung (1.15). There was indication of a positive association between alcohol consumption and risk of melanoma and prostate cancer. Alcohol consumption and risk of Hodgkin’s and Non-Hodgkin’s lymphomas were inversely associated.Conclusions:Alcohol increases risk of cancer of oral cavity and pharynx, oesophagus, colorectum, liver, larynx and female breast. There is accumulating evidence that alcohol drinking is associated with some other cancers such as pancreas and prostate cancer and melanoma.

Gastric Cancer: Descriptive Epidemiology, Risk Factors, Screening, and Prevention

Less than a century ago, gastric cancer was the most common cancer in the United States and perhaps throughout the world. Despite its worldwide decline in incidence over the past century, gastric cancer remains a major killer across the globe. This article reviews the epidemiology, screening, and prevention of gastric cancer. We first discuss the descriptive epidemiology of gastric cancer, including its incidence, survival, mortality, and trends over time. Next, we characterize the risk factors for gastric cancer, both environmental and genetic. Serologic markers and histological precursor lesions of gastric cancer and early detection of gastric cancer using these markers are reviewed. Finally, we discuss prevention strategies and provide suggestions for further research. Cancer Epidemiol Biomarkers Prev; 23(5); 700–13. ©2014 AACR.

Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study

Objective To investigate the association between tea drinking habits in Golestan province, northern Iran, and risk of oesophageal squamous cell carcinoma. Design Population based case-control study. In addition, patterns of tea drinking and temperature at which tea was drunk were measured among healthy participants in a cohort study. Setting Golestan province, northern Iran, an area with a high incidence of oesophageal squamous cell carcinoma. Participants 300 histologically proved cases of oesophageal squamous cell carcinoma and 571 matched neighbourhood controls in the case-control study and 48 582 participants in the cohort study. Main outcome measure Odds ratio of oesophageal squamous cell carcinoma associated with drinking hot tea. Results Nearly all (98%) of the cohort participants drank black tea regularly, with a mean volume consumed of over one litre a day. 39.0% of participants drank their tea at temperatures less than 60°C, 38.9% at 60-64°C, and 22.0% at 65°C or higher. A moderate agreement was found between reported tea drinking temperature and actual temperature measurements (weighted κ 0.49). The results of the case-control study showed that compared with drinking lukewarm or warm tea, drinking hot tea (odds ratio 2.07, 95% confidence interval 1.28 to 3.35) or very hot tea (8.16, 3.93 to 16.9) was associated with an increased risk of oesophageal cancer. Likewise, compared with drinking tea four or more minutes after being poured, drinking tea 2-3 minutes after pouring (2.49, 1.62 to 3.83) or less than two minutes after pouring (5.41, 2.63 to 11.1) was associated with a significantly increased risk. A strong agreement was found between responses to the questions on temperature at which tea was drunk and interval from tea being poured to being drunk (weighted κ 0.68). Conclusion Drinking hot tea, a habit common in Golestan province, was strongly associated with a higher risk of oesophageal cancer. Reza Malekzadeh and other authors of this population based case-control study talk about the effect of tea drinking and oesophageal cancer in Golestan province, northern Iran 10.1136/bmj.b929V1

Opium, tobacco, and alcohol use in relation to oesophageal squamous cell carcinoma in a high-risk area of Iran

The very high incidence of oesophageal squamous cell carcinoma (ESCC) in Golestan Province in northeastern Iran was suggested by studies in the 1970s as partly due to opium use, which is not uncommon in this area, but based on limited numbers. From December 2003 to June 2007, we administered a validated structured questionnaire to 300 ESCC cases and 571 controls, matched on neighbourhood of residence, age (±2 years), and sex. We used conditional logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) adjusted for potential confounders. Compared with those who used neither tobacco nor opium, risk of ESCC was increased in those who used tobacco only (OR, 95% CI: 1.70, 1.05–2.73), in those who used opium only (2.12, 1.21–3.74), and in those who used both tobacco and opium (2.35, 1.50–3.67). All forms of tobacco use (cigarettes, hookah, and nass) were associated with higher ESCC risk. Similarly, use of both crude opium and other forms of opium were associated with higher risk. Alcohol consumption was seen in only 2% of the cases and 2% of the controls, and was not associated with ESCC risk.

High-temperature beverages and foods and esophageal cancer risk--a systematic review.

Coffee, tea and maté may cause esophageal cancer (EC) by causing thermal injury to the esophageal mucosa. If so, the risk of EC attributable to thermal injury could be large in populations in which these beverages are commonly consumed. In addition, these drinks may cause or prevent EC via their chemical constituents. Therefore, a large number of epidemiologic studies have investigated the association of an indicator of amount or temperature of use of these drinks or other hot foods and beverages with risk of EC. We conducted a systematic review of these studies and report the results for amount and temperature of use separately. By searching PubMed and the ISI, we found 59 eligible studies. For coffee and tea, there was little evidence for an association between amount of use and EC risk; however, the majority of studies showed an increased risk of EC associated with higher drinking temperature which was statistically significant in most of them. For maté drinking, the number of studies was limited, but they consistently showed that EC risk increased with both amount consumed and temperature, and these 2 were independent risk factors. For other hot foods and drinks, over half of the studies showed statistically significant increased risks of EC associated with higher temperature of intake. Overall, the available results strongly suggest that high‐temperature beverage drinking increases the risk of EC. Future studies will require standardized strategies that allow for combining data and results should be reported by histological subtypes of EC.

A meta-analysis on alcohol drinking and gastric cancer risk

BACKGROUND Whether an association between alcohol drinking and gastric cancer risk exists is an open question. In order to provide a definite quantification of the association between alcohol drinking and gastric cancer risk, we conducted a meta-analysis of available data. PATIENTS AND METHODS We carried out a PubMed search of articles published up to June 2010 and identified 44 case-control and 15 cohort studies, including a total of 34 557 gastric cancer cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates. We carried out a dose-risk analysis using nonlinear random-effects meta-regression models. RESULTS Compared with nondrinkers, the pooled relative risk (RR) was 1.07 [95% confidence interval (CI) 1.01-1.13] for alcohol drinkers and 1.20 (95% CI 1.01-1.44) for heavy alcohol drinkers (≥4 drinks per day). The pooled estimates were apparently higher for gastric noncardia (RR for heavy drinkers = 1.17, 95% CI 0.78-1.75) than for gastric cardia (RR = 0.99, 95% CI 0.67-1.47) adenocarcinoma. The dose-risk model estimated a RR of 0.95 (95% CI 0.91-0.99) for 10 g/day and 1.14 (95% CI 1.08-1.21) for 50 g/day. CONCLUSIONS This meta-analysis provides definite evidence of a lack of association between moderate alcohol drinking and gastric cancer risk. There was, however, a positive association with heavy alcohol drinking.BACKGROUND Whether an association between alcohol drinking and gastric cancer risk exists is an open question. In order to provide a definite quantification of the association between alcohol drinking and gastric cancer risk, we conducted a meta-analysis of available data. PATIENTS AND METHODS We carried out a PubMed search of articles published up to June 2010 and identified 44 case-control and 15 cohort studies, including a total of 34 557 gastric cancer cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates. We carried out a dose-risk analysis using nonlinear random-effects meta-regression models. RESULTS Compared with nondrinkers, the pooled relative risk (RR) was 1.07 [95% confidence interval (CI) 1.01-1.13] for alcohol drinkers and 1.20 (95% CI 1.01-1.44) for heavy alcohol drinkers (≥4 drinks per day). The pooled estimates were apparently higher for gastric noncardia (RR for heavy drinkers=1.17, 95% CI 0.78-1.75) than for gastric cardia (RR=0.99, 95% CI 0.67-1.47) adenocarcinoma. The dose-risk model estimated a RR of 0.95 (95% CI 0.91-0.99) for 10 g/day and 1.14 (95% CI 1.08-1.21) for 50 g/day. CONCLUSIONS This meta-analysis provides definite evidence of a lack of association between moderate alcohol drinking and gastric cancer risk. There was, however, a positive association with heavy alcohol drinking.

Socio-economic status and oesophageal cancer: results from a population-based case–control study in a high-risk area

BACKGROUND Cancer registries in the 1970s showed that parts of Golestan Province in Iran had the highest rate of oesophageal squamous cell carcinoma (OSCC) in the world. More recent studies have shown that while rates are still high, they are approximately half of what they were before, which might be attributable to improved socio-economic status (SES) and living conditions in this area. We examined a wide range of SES indicators to investigate the association between different SES components and risk of OSCC in the region. METHODS Data were obtained from a population-based case-control study conducted between 2003 and 2007 with 300 histologically proven OSCC cases and 571 matched neighbourhood controls. We used conditional logistic regression to compare cases and controls for individual SES indicators, for a composite wealth score constructed using multiple correspondence analysis, and for factors obtained from factors analysis. RESULTS We found that various dimensions of SES, such as education, wealth and being married were all inversely related to OSCC. The strongest inverse association was found with education. Compared with no education, the adjusted odds ratios (95% confidence intervals) for primary education and high school or beyond were 0.52 (0.27-0.98) and 0.20 (0.06-0.65), respectively. CONCLUSIONS The strong association of SES with OSCC after adjustment for known risk factors implies the presence of yet unidentified risk factors that are correlated with our SES measures; identification of these factors could be the target of future studies. Our results also emphasize the importance of using multiple SES measures in epidemiological studies.