Tobacco smoking and intestinal metaplasia: Systematic review and meta-analysis

BACKGROUND

The evaluation of specific risk factors for early endpoints in the gastric carcinogenesis pathway may further contribute to the understanding of gastric cancer aetiology.

AIMS

To quantify the relation between smoking and intestinal metaplasia through systematic review and meta-analysis.

METHODS

Articles providing data on the association between smoking and intestinal metaplasia were identified in PubMed(®), Scopus(®) and Web of Science™, searched until April 2014, and through backward citation tracking. Summary odds ratio estimates and 95% confidence intervals were computed using the DerSimonian and Laird method. Heterogeneity was quantitatively assessed using the I(2) statistic.

RESULTS

A total of 32 articles were included in this systematic review and 19 provided data for meta-analysis. Smoking was defined as ever vs. never (crude estimates, six studies, summary odds ratio=1.54, 95% confidence interval: 1.12-2.12, I(2)=67.4%; adjusted estimates, seven studies, summary odds ratio=1.26, 95% confidence interval: 0.98-1.61, I(2)=65.0%) and current vs. non-smokers (crude estimates, seven studies, summary odds ratio=1.27, 95% confidence interval: 0.88-1.84, I(2)=73.4%; adjusted estimates, two studies, summary odds ratio 1.49, 95% confidence interval: 0.99-2.25, I(2)=0.0%).

CONCLUSION

The weak and non-statistically significant association found through meta-analysis of the available evidence does not confirm smoking as an independent risk factor for intestinal metaplasia.

Genetic variants in the IL1A gene region contribute to intestinal-type gastric carcinoma susceptibility in European populations

The most studied genetic susceptibility factors involved in gastric carcinoma (GC) risk are polymorphisms in the inflammation-linked genes interleukin 1 (IL1) B and IL1RN. Despite the evidence pointing to the IL1 region, definite functional variants reproducible across populations of different genetic background have not been discovered so far. A high density linkage disequilibrium (LD) map of the IL1 gene cluster was established using HapMap to identify haplotype tagSNPs. Eighty-seven SNPs were genotyped in a Portuguese case-control study (358 cases, 1,485 controls) for the discovery analysis. A replication study, including a subset of those tagSNPs (43), was performed in an independent analysis (EPIC-EurGast) containing individuals from 10 European countries (365 cases, 1284 controls). Single SNP and haplotype block associations were determined for GC overall and anatomopathological subtypes. The most robust association was observed for SNP rs17042407, 16Kb upstream of the IL1A gene. Although several other SNP associations were observed, only the inverse association of rs17042407 allele C with GC of the intestinal type was observed in both studies, retaining significance after multiple testing correction (p = 0.0042) in the combined analysis. The haplotype analysis of the IL1A LD block in the combined dataset revealed the association between a common haplotype carrying the rs17042407 variant and GC, particularly of the intestinal type (p = 3.1 × 10(-5) ) and non cardia localisation (p = 4.6 × 10(-3) ). These results confirm the association of IL1 gene variants with GC and reveal a novel SNP and haplotypes in the IL1A region associated with intestinal type GC in European populations.

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.

Sociodemographic determinants of prevalence and incidence of Helicobacter pylori infection in Portuguese adults

BACKGROUND

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.

MATERIAL AND METHODS

A representative sample of noninstitutionalized adult inhabitants of Porto (n = 2067) was evaluated by ELISA (IgG) and a subsample (n = 412) was tested by Western Blot to assess infection with CagA-positive strains. Modified Poisson and Poisson regression models were used to estimate crude and sex-, age-, and education-adjusted prevalence ratios (PR) and incidence rate ratios (RR), respectively.

RESULTS

The prevalence of H. pylori infection was 84.2% [95% confidence interval (95%CI): 82.4-86.1]. It increased across age-groups in the more educated subjects, (18-30 years: 72.6%; ≥71 years: 88.1%; p for trend <0.001) and decreased with education in the younger (≤4 schooling years: 100.0%; ≥10 schooling years: 72.6%; p for trend <0.001). Living in a more deprived neighborhood was associated with a higher prevalence of infection, only in the younger (PR = 1.20, 95%CI: 1.03-1.38) and more educated participants (PR = 1.15, 95%CI: 1.03-1.29). Among the infected, the proportion with CagA-positive strains was 61.7% (95%CI: 56.6-66.9). The incidence rate was 3.6/100 person-years (median follow-up: 3 years; 95%CI: 2.1-6.2), lower among the more educated (≥10 vs ≤9: RR = 0.25, 95%CI: 0.06-0.96). The seroreversion rate was 1.0/100 person-years (95%CI: 0.6-1.7).

CONCLUSIONS

The prevalence of infection among adults is still very high in Portugal, suggesting that stomach cancer rates will remain high over the next few decades.

Cytology use for cervical cancer screening in Portugal: results from the 2005/2006 National Health Survey

BACKGROUND

Understanding the patterns of cervical cytology use in preventive care may provide useful information for an efficient transition from opportunistic screening to organized programmes. We aimed to identify the determinants of non-use and underuse of cervical cytology in Portuguese women.

METHODS

As part of the fourth National Health Survey (2005/2006), 2191 women aged between 25 and 64 years were evaluated. The previous use of cervical cytology was classified as never or ever, and, among the latter, those having performed the latest cytology testing >5 years before were considered to underuse cervical cytology. We assessed the determinants of non-use and underuse through age- and education-adjusted odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs).

RESULTS

Overall, 23.5% of women had never used cervical cytology and 10.7% reported underuse. This prevalence increased with age and decreased with education and income. Compared with the national mean, the lowest risk of non-use and underuse was observed in Norte (non-use: OR = 0.31, 95% CI: 0.23-0.42; underuse: OR = 0.60, 95% CI: 0.40-0.91) and the highest in Alentejo (non-use: OR = 2.33, 95% CI: 1.78-3.06; underuse: OR = 2.37, 95% CI: 1.43-3.93). Women without a private health insurance (OR = 2.65, 95% CI: 1.29-5.47), who had no doctor appointments in the preceding 3 months (OR = 2.06, 95% CI: 1.22-3.48) and those who had never performed a mammography (OR = 17.78, 95% CI: 9.09-34.78) were more likely to have never performed a cervical cytology.

CONCLUSION

This study shows inequalities in the use of cervical cancer screening in Portugal and provides useful information for a better allocation of resources for cancer screening.

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.

Changing patterns of cardiovascular diseases and cancer mortality in Portugal, 1980-2010

BACKGROUND

Cardiovascular diseases and cancer are jointly responsible for more than half all deaths in Portugal. They also share some important risk factors and act as mutual competing risks. We aimed firstly to describe time trends in death rates and years of life lost due to cardiovascular diseases and cancer in the Portuguese population from 1980 to 2010; and secondly to quantify the contribution of the variation in population and age structure, and age-independent "risk" by cardiovascular or oncological causes to the change in the corresponding number of deaths.

METHODS

We estimated the annual percent change in age-standardized mortality rates from cardiovascular diseases and cancer, in each sex. The specific contribution of demographic changes (due to changes in population size and in population age structure) and the variation in the age-independent "risk" of dying from the disease to the observed trends in the number of deaths was quantified using the tool RiskDiff. Years of life lost were computed using the Global Burden of Disease method.

RESULTS

Among men, the mortality rate from all cardiovascular diseases was more than two-fold higher than cancer mortality in 1980. However, three decades later mortality from cancer surpassed cardiovascular diseases. After 2005, the years of life lost from cancer were also higher than from cardiovascular diseases. Among women, despite the decrease in death rates, cardiovascular diseases remained the leading cause of death in 2010 and their absolute burden was higher than that of cancers across the whole period, mainly due to more events in older women.

CONCLUSIONS

In Portugal, the 20th century witnessed a dramatic decrease in the cardiovascular disease mortality and YLL, and the transition towards cancer. In more recent years, the highest burdens of disease came from cancers in men and from cardiovascular diseases in women.

Prediagnosis lifestyle exposures and survival of gastric cancer patients: a cohort study from Portugal

BACKGROUND

Dietary habits and smoking are recognised as important gastric cancer determinants. However, their impact on prognosis remains poorly understood. We aimed to quantify the association between lifestyles and survival of gastric cancer patients.

METHODS

In 2001-2006, 568 patients were recruited in the two major public hospitals in the north of Portugal. Participants were inquired about smoking and dietary habits regarding the year preceding the diagnosis. The vital status of all participants, up to 2011 (maximum follow-up: 10 years), was assessed through the North Region Cancer Registry. Cox proportional hazards regression models were used to estimate adjusted (at least for age, sex and education) hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

No significant differences in gastric cancer survival were observed according to smoking status (current vs never smokers, HR=1.00, 95% CI: 0.72-1.38) or alcohol intake (current vs never consumers, HR=0.87, 95% CI: 0.61-1.25). Only a dietary pattern (high consumptions of most food groups and low vegetable soup intake) was significantly associated with a better prognosis among patients with the extent of disease classified as regional spread (HR=0.45, 95% CI: 0.22-0.93).

CONCLUSION

This study shows that prediagnosis lifestyles have a small impact in the survival of gastric cancer patients.

The effect of osteoarthritis definition on prevalence and incidence estimates: a systematic review

OBJECTIVE

To understand the differences in prevalence and incidence estimates of osteoarthritis (OA), according to case definition, in knee, hip and hand joints.

METHOD

A systematic review was carried out in PUBMED and SCOPUS databases comprising the date of publication period from January 1995 to February 2011. We attempted to summarise data on the incidence and prevalence of OA according to different methods of assessment: self-reported, radiographic and symptomatic OA (clinical plus radiographic). Prevalence estimates were combined through meta-analysis and between-study heterogeneity was quantified.

RESULTS

Seventy-two papers were reviewed (nine on incidence and 63 on prevalence). Higher OA prevalences are seen when radiographic OA definition was used for all age groups. Prevalence meta-analysis showed high heterogeneity between studies even in each specific joint and using the same OA definition. Although the knee is the most studied joint, the highest OA prevalence estimates were found in hand joints. OA of the knee tends to be more prevalent in women than in men independently of the OA definition used, but no gender differences were found in hip and hand OA. Insufficient data for incidence studies didn't allow us to make any comparison according to joint site or OA definition.

CONCLUSIONS

Radiographic case definition of OA presented the highest prevalences. Within each joint site, self-reported and symptomatic OA definitions appear to present similar estimates. The high heterogeneity found in the studies limited further conclusions.

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.

Salt intake and type of intestinal metaplasia in Helicobacter pylori-infected Portuguese men

The relation between salt intake and intestinal metaplasia (IM) types and the potential interaction with H. pylori virulence are poorly understood and may contribute to further understand gastric carcinogenesis. We quantified the association between dietary salt exposure and complete, incomplete, and mixed IM, taking into account the potential effect modification according to the virulence of H. pylori infecting strains. H. pylori-infected male volunteers (n = 233) underwent an upper digestive endoscopy and completed questionnaires comprising different measures of salt exposure (main food items/groups contributing to dietary salt intake, estimated dietary sodium intake, visual analogical scale for salt intake, preference for salty/salted foods). A histological diagnosis was assigned based on the most severe lesion observed. H. pylori virulence was assessed by characterizing vacA and cagA genes. Odds ratios were estimated through age- and education-adjusted logistic regression models. The risk of IM was not significantly increased in H. pylori infected subjects with higher levels of salt consumption. The lack of association was consistent across measures of salt exposure, categories of H. pylori virulence, and types of IM. In conclusion, in this H. pylori positive population, salt intake did not increase the risk of any IM type, regardless of the virulence of the infecting strains.

Relevance of high virulence Helicobacter pylori strains and futility of CDX2 expression for predicting intestinal metaplasia after eradication of infection

OBJECTIVE

Different Helicobacter pylori genotypes are associated with distinct inflammatory responses and consequent development of pre-neoplastic lesions, namely intestinal metaplasia (IM), which is dependent on the expression of CDX2. We aimed to evaluate IM progression/regression in the context of H. pylori eradication, bringing into play the effect of the virulence of infecting H. pylori strains and the hypothesis that CDX2 expression might be a marker for later development of IM.

MATERIAL AND METHODS

Sixty-five male volunteers were evaluated by endoscopy before H. pylori eradication and after a median six-year follow-up. Histological diagnosis was performed at baseline and follow-up, and baseline H. pylori genotypes and CDX2 expression in non-metaplastic foci were also assessed.

RESULTS

Fifty-one individuals remained free from infection at follow-up. Six out of 27 who had no metaplastic lesions at baseline developed IM. CDX2 nuclear expression was observed in 15 of the 21 cases (71.4%) showing no progression to IM, and in three out of six cases (50%) with progression to IM (p = 0.367). Six of the 24 cases with IM at baseline showed regression to less severe outcomes, which was less frequent in those infected with high-virulence strains (7.7% vs. 50%, p = 0.047). In the latter there is a significant persistence of lymphoid follicles.

CONCLUSIONS

Our results support that under infection with high virulence H. pylori strains, IM is a point of difficult return in the gastric carcinogenic pathway. The appearance of CDX-expressing cells in non-metaplastic foci was not associated with the development of IM during the six-year follow-up.

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.

The state of the art of cancer control in 30 European countries in 2008

Inequalities in cancer incidence, mortality and survival represent a major challenge for public health. Addressing this challenge requires complex and multidisciplinary approaches. Sharing successful experiences from across Europe may therefore be of benefit. We describe the state of the art of cancer control structures in the 27 European Union countries, plus Iceland, Norway and Switzerland, at the beginning of 2008. Information on cancer plans, cancer registries, cancer screening, Human Papillomavirus (HPV) vaccination and smoking restrictions in each country was identified through PubMed, the official websites of national and international organizations and Google searches. Experts and/or health authorities from each country completed and validated the information. Sixteen countries had implemented national cancer plans in 2008. Twenty four countries had population-based cancer registries with 100% coverage. The exceptions were Greece and Luxembourg (no population-based registry yet), France, Italy and Spain (<50%), and Switzerland (62%). In 9 countries, population coverage of breast cancer screening was 100% with participation ranging from 26 to 87%; 8 countries did not have organized programmes. Seven countries had cervical cancer screening programmes with 100% coverage with participation ranging from 10 to 80%; 8 countries had no organized programme. Nine countries had announced national HPV vaccination policies by early 2008. Six countries had organized colorectal cancer screening programmes. Five countries had complete bans on smoking in public places. There is wide international heterogeneity in cancer control structures in Europe. This provides considerable scope and motivation for cooperation and sharing of experience.

Factors contributing to the underestimation of Helicobacter pylori-associated gastric cancer risk in a high-prevalence population

OBJECTIVE

This study aimed to identify sources of underestimation of the association between Helicobacter pylori infection and non-cardia gastric cancer, in a high-risk European population.

METHODS

Non-cardia gastric cancer patients (n = 420) recruited in two major hospitals in North of Portugal and population controls (n = 1,389) were evaluated. Whole-cell IgG antibodies against H. pylori were quantified by ELISA and Western Blot testing was conducted in a subsample (272 cases and 186 controls) allowing for the detection of current infection marker and CagA. Sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were computed.

RESULTS

When assessing infection by ELISA, the OR for its association with gastric cancer decreases and reverts as IgG titers increased, from 1.96 (95% CI: 1.09-3.54) for borderline positive results (16.0-21.9 RU/ml) to 0.52 (95% CI: 0.36-0.74) for the highest IgG levels (> or = 102.0 RU/ml). The same pattern was observed across strata of age and blood collection timing with stronger associations among younger subjects and those providing blood samples earlier after diagnosis. The presence of CagA (Western Blot) was associated with an increased risk of gastric cancer (OR = 11.32; 95% CI: 5.64-22.73).

CONCLUSION

The use of methods with low sensitivity to detect past infection leads to a substantial underestimation of gastric cancer risk in high-prevalence settings.

Association between cytokine gene polymorphisms and gastric precancerous lesions: systematic review and meta-analysis

Polymorphisms within interleukin-1 (IL1) and tumor necrosis factor alpha (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; I(2) = 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; I(2) = 65.7%; 13 studies) or TNFA-308 genotypes (AA versus GG: OR, 0.93; 95% CI, 0.35-2.43; I(2) = 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.

Sensitivity is not an intrinsic property of a diagnostic test: empirical evidence from histological diagnosis of Helicobacter pylori infection

Background

We aimed to provide empirical evidence of how spectrum effects can affect the sensitivity of histological assessment of Helicobacter pylori infection, which may contribute to explain the heterogeneity in prevalence estimates across populations with expectedly similar prevalence.

Methods

Cross-sectional evaluation of dyspeptic subjects undergoing upper digestive endoscopy, including collection of biopsy specimens from the greater curvature of the antrum for assessment of H. pylori infection by histopathological study and polymerase chain reaction (PCR), from Portugal (n = 106) and Mozambique (n = 102) following the same standardized protocol.

Results

In the Portuguese sample the prevalence of infection was 95.3% by histological assessment and 98.1% by PCR. In the Mozambican sample the prevalence was 63.7% and 93.1%, respectively. Among those classified as infected by PCR, the sensitivity of histological assessment was 96.2% among the Portuguese and 66.3% among the Mozambican. Among those testing positive by both methods, 5.0% of the Portuguese and 20.6% of the Mozambican had mild density of colonization.

Conclusions

This study shows a lower sensitivity of histological assessment of H. pylori infection in Mozambican dyspeptic patients compared to the Portuguese, which may be explained by differences in the density of colonization, and may contribute to explain the heterogeneity in prevalence estimates across African settings.

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 participant's 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.

Influence of chronological aging on the survival and nucleotide content of Saccharomyces cerevisiae cells grown in different conditions: occurrence of a high concentration of UDP-N-acetylglucosamine in stationary cells grown in 2% glucose

Saccharomyces cerevisiae cells (strain W303) grown in a minimal medium (containing 2% or 0.1% glucose) until exponential or stationary phase, were subjected to chronological aging in water, and yeast viability and nucleotide content were analyzed along several days of nutrient starvation. Cells collected in exponential phase (whether grown in the presence of 0.1% or 2% glucose) were viable up to five days and thereafter the viability decreased linearly with a half-survival rate of around eight days. ATP and other nucleoside triphosphates decreased similarly in both cases. Cells collected in stationary phase, and transferred to water, behaved differently whether grown in 0.1% or in 2% glucose, with a half-survival life of around nine and 28 days respectively. A double mutant in glycogen synthase (gsy1delta gsy2delta) and its isogenic wild-type strain, grown to stationary phase in 2% glucose, presented a similar half-survival life of around eight days. The W303 cells grown to stationary phase in the presence of 2% glucose showed a 7-fold increase of UDP-N-acetylglucosamine (UDP-GlcNAc) as compared with the level present in the cells grown in any of the other three metabolic situations. The nature of UDP-GlcNAc was established by MALDI-TOF ionization analysis. It is also worth noting that the rate of decay of NAD+ was lower than that of ATP in any of the situations here considered.