Bárbara Peleteiro

Worldwide trends in gastric cancer mortality (1980-2011), with predictions to 2015, and incidence by subtype.

Gastric cancer incidence and mortality decreased substantially over the last decades in most countries worldwide, with differences in the trends and distribution of the main topographies across regions. To monitor recent mortality trends (1980-2011) and to compute short-term predictions (2015) of gastric cancer mortality in selected countries worldwide, we analysed mortality data provided by the World Health Organization. We also analysed incidence of cardia and non-cardia cancers using data from Cancer Incidence in Five Continents (2003-2007). The joinpoint regression over the most recent calendar periods gave estimated annual percent changes (EAPC) around -3% for the European Union (EU) and major European countries, as well as in Japan and Korea, and around -2% in North America and major Latin American countries. In the United States of America (USA), EU and other major countries worldwide, the EAPC, however, were lower than in previous years. The predictions for 2015 show that a levelling off of rates is expected in the USA and a few other countries. The relative contribution of cardia and non-cardia gastric cancers to the overall number of cases varies widely, with a generally higher proportion of cardia cancers in countries with lower gastric cancer incidence and mortality rates (e.g. the USA, Canada and Denmark). Despite the favourable mortality trends worldwide, in some countries the declines are becoming less marked. There still is the need to control Helicobacter pylori infection and other risk factors, as well as to improve diagnosis and management, to further reduce the burden of gastric cancer.

Dietary patterns and colorectal cancer: systematic review and meta-analysis.

Studies on the association between single foods or nutrients and colorectal cancer have provided inconsistent results. Previous reviews did not conduct a quantitative synthesis of the relation with dietary patterns. We conducted a systematic review and meta-analysis of studies addressing the association between dietary patterns and colorectal cancer. Studies quantifying the association between dietary patterns (defined a posteriori) and colorectal cancer were identified in PubMed (until 01.08.2010) and through backward and forward citation tracking (ISI Web of Science and Scopus). Summary relative risk (RR) estimates and 95% confidence intervals (95% CI) were computed for highest versus lowest levels of exposure, for colon cancer (CC) and rectal cancer (RC), and for proximal and distal CC, by random effects meta-analysis. Heterogeneity was quantified using the I2 statistic. Eight cohort and eight case–control studies defining patterns through principal components and factor analyses were included in the systematic review. Meta-analyses were conducted for three patterns: (i) ‘drinker,’ characterized by high alcohol consumption (CC: RRcombined=0.96, 95% CI: 0.82–1.12, I2=0.6%; RC: RRcombined=0.83, 95% CI: 0.47–1.45, I2=65.1%); (ii) ‘healthy,’ characterized by high fruit/vegetables consumption (CC: RRcombined=0.80, 95% CI: 0.70–0.90, I2=55.1%; RC: RRcombined=1.02, 95% CI: 0.89–1.17, I2=10.8%); (iii) ‘western,’ characterized by high red/processed meat consumption (CC: RRcombined=1.29, 95% CI: 1.13–1.48, I2=31.7%; RC: RRcombined=1.13, 95% CI: 0.92–1.39, I2=40.6%). Summary estimates for proximal and distal CC were similar. The risk of CC was increased with patterns characterized by high intake of red and processed meat and decreased with those labelled as ‘healthy.’ No significant associations were observed for RC.

Erratum to: Prevalence of Helicobacter pylori Infection Worldwide: A Systematic Review of Studies with National Coverage

The systematic assessment of large population-based surveys addressing the prevalence of Helicobacter pylori infection may provide robust evidence for understanding the trends in the exposure to this major risk factor across settings with distinct patterns of gastric cancer variation. Our aim was to describe the prevalence of H. pylori infection in different countries and periods, through systematic review of the literature. We searched PubMed from inception up to September 2013 to identify original studies reporting on the prevalence of H. pylori, and only those evaluating samples with national coverage were included. We identified 37 eligible studies including data for 22 countries. The prevalences were higher in Central/South America and Asia, and at least two-fold higher in countries with high gastric cancer incidence. In most countries presenting data for different time periods, the prevalences were usually lower in the most recent surveys. However, there was little variation in settings where prevalences were already low. Among countries with high prevalence of H. pylori infection there is an ample scope for reducing its burden in the next decades, whereas further declines in settings with already low prevalences will require more intensive efforts.

Salt intake and gastric cancer risk according to Helicobacter pylori infection, smoking, tumour site and histological type.

Background:Although salt intake is considered a probable risk factor for gastric cancer, relevant studies have provided heterogeneous results, and the magnitude of the association has not been accurately quantified.Methods:To quantify gastric cancer risk in relation to dietary salt exposure according to Helicobacter pylori infection status and virulence, smoking, tumour site, and histological type, we evaluated 422 gastric cancer cases and 649 community controls. Salt exposure was estimated in the year before the onset of symptoms through: sodium intake (estimated by a food frequency questionnaire (FFQ)); main food items/groups contributing to dietary sodium intake; visual analogical scale for salt intake preference; use of table salt; and duration of refrigerator ownership.Results:Comparing subjects with the highest with those with the lowest salt exposure (3rd vs 1st third), sodium intake (OR=2.01, 95% CI: 1.16–3.46), consumption of food items with high contribution to sodium intake (OR=2.54, 95% CI: 1.56–4.14) and salt intake evaluated by visual analogical scale (OR=1.83, 95% CI: 1.28–2.63) were associated with an increased gastric cancer risk. Subjects owning a refrigerator for >50 years had a lower risk for gastric cancer (OR=0.28, 95% CI: 0.14–0.57). These associations were observed regardless of H. pylori infection status and virulence, smoking, tumour site or histological type.Conclusion:Our results support the view that salt intake is an important dietary risk factor for gastric cancer, and confirms the evidence of no differences in risk according to H. pylori infection and virulence, smoking, tumour site and histological type.

The role of Helicobacter pylori infection in the web of gastric cancer causation

The decline in gastric cancer mortality is a major achievement in cancer control. It has been attributed to a set of factors related to the improvement of the populations’ living conditions, namely the increase in the consumption of fruit and vegetables and the decrease in salt intake, and therefore labelled as an ‘unplanned triumph’. In the last decades, however, we witnessed the gradual acceptance of Helicobacter pylori infection as the most important environmental factor contributing to the occurrence of gastric cancer. The potential for further reducing the burden of cancer by acting on a single modifiable exposure, that is, preventing or treating infection, and the extent to which it may be achieved, requires an in-depth knowledge of the contribution of H. pylori infection to the causal mechanisms leading to cancer. We propose a conceptual framework for the interpretation of the role of H. pylori infection in the web of gastric cancer causation, taking into account the nosological heterogeneity of gastric cancer, the induction period for the action of H. pylori infection and its potential role as a necessary component cause.

Sociodemographic Determinants of Prevalence and Incidence of Helicobacter pylori Infection in Portuguese Adults

Understanding the determinants of Helicobacter pylori infection in adults is essential to predict the burden of H. pylori‐related diseases. We aimed to estimate the prevalence and incidence of H. pylori infection and to identify its major sociodemographic correlates in an urban population from the North of Portugal.

Smoking, Helicobacter pylori Virulence, and Type of Intestinal Metaplasia in Portuguese Males

High-virulence Helicobacter pylori strains and smoking increase the risk of gastric precancerous lesions. However, its association with specific types of intestinal metaplasia has been poorly studied. We aimed to quantify the association between different types of intestinal metaplasia (complete, incomplete, and mixed) and these two risk factors. Male volunteers (n = 227) underwent an upper digestive endoscopy and completed symptoms and lifestyle questionnaires. A histologic diagnosis was assigned based on the lesions found in any of the biopsy specimens (antrum, body, or incisura). H. pylori vacA and cagA were directly genotyped by multiplex PCR and reverse hybridization. Each participants smoking status at the time of endoscopy was assessed. Logistic and multinomial logistic regression models were fitted (including H. pylori virulence, smoking, age, and education as independent variables) using normal/chronic nonatrophic gastritis as the reference category. Compared with never smokers infected with low-virulence strains, the risk of intestinal metaplasia was increased in subjects infected with high-virulence strains [odds ratio (OR), 5.74; 95% confidence interval (95% CI), 1.68-19.63] and in ever smokers (OR, 3.54; 95% CI, 1.30-9.61). In ever smokers infected with high-virulence H. pylori strains, the risk of intestinal metaplasia was further increased (OR, 8.61; 95% CI, 3.07-24.17). Infection with high-virulence strains significantly increased the risk of incomplete (OR, 9.81; 95% CI, 2.39-40.31) and mixed (OR, 3.28; 95% CI, 1.51-7.14) intestinal metaplasia. Complete (OR, 2.82; 95% CI, 1.01-7.88) and mixed (OR, 2.97; 95% CI, 1.12-7.84) intestinal metaplasia were more frequent among ever smokers. High-virulence H. pylori strains and smoking are differentially associated with the complete and incomplete types of intestinal metaplasia, suggesting divergent pathways in gastric carcinogenesis. (Cancer Epidemiol Biomarkers Prev 2007;16(2):322–6)

Association Between Cytokine Gene Polymorphisms and Gastric Precancerous Lesions: Systematic Review and Meta-analysis

Polymorphisms within interleukin-1 (IL1) and tumor necrosis factor α (TNFA) gene clusters are associated with an increased risk of gastric cancer. However, their role in gastric precancerous lesions remains poorly understood. Our objective was to perform a meta-analysis of studies addressing the association between IL1B-511, IL1RN variable number of tandem repeat, and TNFA-308 gene polymorphisms and gastric precancerous lesions, including original data from Portugal and Mozambique. Published studies on the association between these cytokine gene polymorphisms and gastric precancerous lesions were identified by systematic review, and estimates of the association were combined using random-effects meta-analysis taking into account new data obtained from Portuguese volunteer shipyard workers (n = 215) and Mozambican dyspeptic patients (n = 96) who underwent endoscopic and pathologic evaluation following the same protocol. Odds ratio (OR) estimates for intestinal metaplasia were 2.83 [95% confidence interval (95% CI), 1.15-6.96] for the IL1RN*22 genotype, 1.86 (95% CI, 1.03-3.36) for IL1B-511 T carriers, and 0.59 (95% CI, 0.12-3.04) for the TNFA-308*AA genotype in the Portuguese sample. All Mozambican subjects with intestinal metaplasia were T carriers for IL1B-511 and none had the 2 allele for IL1RN. In meta-analysis, IL1RN*22 genotype was associated with an increased risk of gastric precancerous lesions (22 versus LL: OR, 2.27; 95% CI, 1.40-3.70; I2 = 26.4%; 12 studies). No such association was found for the IL1B-511 (TT versus CC: OR, 1.34; 95% CI, 0.87-2.07; I2 = 65.7%; 13 studies) or TNFA-308 genotypes (AA versus GG: OR, 0.93; 95% CI, 0.35-2.43; I2 = 0.0%; 7 studies). The IL1RN*22 genotype seems to consistently increase the risk of gastric precancerous lesions, supporting a role for this polymorphism in the early stages of gastric carcinogenesis. Cancer Epidemiol Biomarkers Prev; 19(3); 762–76

Prevalence, incidence and risk factors for Helicobacter pylori infection in a cohort of Portuguese adolescents (EpiTeen)

BACKGROUND Helicobacter pylori infection is acquired mainly during childhood, but it may occur throughout life. Understanding the determinants of infection at different ages is essential to clarify dynamics of H. pylori related diseases and to design preventive strategies. AIM To estimate the prevalence of H. pylori infection at the age of 13 and the incidence after a 3-year follow-up and to identify risk factors for infection. SUBJECTS AND METHODS Adolescents born in 1990 were recruited in schools from Porto. Whole-cell anti-H. pylori IgG antibodies were quantified by ELISA. Prevalence ratios (PR) and incidence rate ratios (RR) adjusted for parental education were computed at baseline (n = 1312) and at follow-up (n = 280). RESULTS The prevalence was 66.2%, lower in subjects with more educated parents (PR = 0.72, 95%CI: 0.63-0.82), and higher for those having more than one sibling (PR = 1.10, 95%CI: 1.02-1.19) and for smokers (PR = 1.11, 95%CI: 1.02-1.20). The incidence was 4.1/100 person-years. Smoking (RR = 2.35, 95%CI: 1.16-4.75) and type of school (RR = 0.38, 95%CI: 0.16-0.95) were associated with the incidence of infection. CONCLUSIONS Prevalence and incidence of H. pylori infection were high, suggesting that gastric cancer will remain an important public health problem in this generation of Portuguese. We identified smoking as a modifiable risk factor for infection.

Dietary patterns and gastric cancer in a Portuguese urban population

Dietary patterns analysis is a powerful technique to study the relations between diet and cancer. We aimed to quantify the association between dietary patterns and gastric cancer, by location and histological type, according to Helicobacter pylori infection status. We analyzed 591 incident cases of gastric adenocarcinoma and 1,463 community controls. Dietary intake was assessed using a validated food frequency questionnaire. Principal components and cluster analyses were used to define dietary patterns. Anti‐H. pylori IgG was assessed by ELISA. Age‐, gender‐, education‐ and total energy intake‐adjusted odds ratios (OR) were computed. Three dietary patterns were identified, with the following main characteristics: (I) high consumption of fruits and dairy products, and low consumption of alcoholic beverages; (II) low consumption of fruit, salads, vegetables, dairy products, fish and meat; (III) high consumptions of most food groups and low vegetable soup intake. Compared to pattern I, the risk of gastric cancer was higher for pattern II (OR = 1.68, 95% CI: 1.31–2.14) but not for pattern III (OR = 0.80, 95% CI: 0.57–1.14), with no effect modification by H. pylori infection. The association was similar for cardia and non‐cardia gastric cancer, but for tumors of the diffuse Laurén histological type, the association was weaker for pattern II vs. I (OR = 1.32, 95% CI: 0.83–2.08) and a protective effect was observed for pattern III vs. I (OR = 0.43, 95% CI: 0.22–0.87). Our results confirm the protective effect of high fruit and vegetables intake, and show a differential association according to histological type. No effect modification by H. pylori infection was observed.