3X FLAG Peptide The prevalence described in the meta
The prevalence described in the meta-analysis and the 95% confidence intervals (CI95%) were estimated by the random effects model, weighted by the size of the study. Heterogeneity across studies was analyzed by the fixed effect model of the inverse variance, and the magnitude of inconsistency was estimated by I-square statistics (I²) .
Subgroup analyses were carried out to investigate H. pylori prevalence by country, sex, age group (<18 years old and ≥18 years old), and 3X FLAG Peptide of data collection from the studies (1987–2000 and 2001–2012), when data were available. Meta-regression was also applied to evaluate the effect of the study year, diagnosis methods, and Human Development Index (https://data.worldbank.org/) (HDI). This analysis considered the HDI of the country and year of study (or closest year available at the website from world bank). Small study effects were evaluated by visual inspection of the funnel plot and linear regression test of funnel plot asymmetry . All analyses were carried out in R, using the meta package .
Discussion The prevalence of H. pylori infection estimated for LAC overall was 57.57%. The estimates obtained herein were lower than those obtained by Hooi et al7 (63.4%;CI95%:59.2;67.6) and Zamani et al6 (59.3%;CI95%:52.9;65.6), even with differences regarding inclusion criteria. The present study also considered the Regional Scielo database (303 studies), and only included population-based studies. Prevalence of H pylori according to sex did not show differences, suggesting that the habits associated with H. pylori infection do not differ across genders in LAC. On the contrary, the findings of Ibrahim  show higher prevalence in male adults (OR:1,11) for America as a whole. Regarding age group, prevalence among adults was higher than in children and adolescents. This increase in prevalence along with age has already been described earlier.  Peleteiro et al observed that the prevalence of H. pylori in the age group up to 20 years oldwere high in Latin American countries in comparison with other countries in the world , from 30% in Argentina to 70% in Mexico. In this meta-analysis, the prevalence of H. pylori in LAC was 52% among children and adolescents, which demonstrates a high presence of this infection, especially in younger age groups. The chronic infection can lead to an increase of risk and in the incidence of gastric cancer. In this study, as well as in Hooi et al and Zamani et al, the prevalence detected in LAC were high, when compared with other regions of the world [6,7].These differences probably reflect the different levels of urbanization, sanitation, access to clean water and socioeconomic conditions. When comparing studies according to the year of data collection (1987–2000 and 2001–2012), no differences were identified in the prevalence of H. pylori. Although, Eusebi et al verified a reduction in prevalence in some countries, depending to the studied years.  Zamami et al identified differences, according to the study year, for Africa, where prevalence of H. pylori infection increased.  The socioeconomic and sanitary changes that occurred in LAC do not seem to have influenced the prevalence of H. pylori infection in this region. Difficult access to treatment, frequent recurrences, and discontinuity in treatment lead to this high prevalence for H. pylori infection. [39,40]A meta-analysis conducted by Corral et al estimated a relapse rate of 7.9 (CI95%: 5.3–10.5) per 100 people-year for H. pylori infection in Latin America . It was also investigated whether heterogeneity could be associated to the diagnosis method in each study, and no changes were observed in the results. For the diagnosis of H. pylori, serology is useful in screening tests, as well as the fecal antigen. The urea breath test is the best non-invasive test to diagnosis H. pylori infections, with high sensitivity and specificity, and was employed in six out of 22 studies. [42,43]