Association between salt intake and gastric atrophy by Helicobacter pylori infection: first results from the Epidemiological Investigation of Gastric Malignancy (ENIGMA).

PURPOSE: Gastric atrophy (GA), usually linked to chronic infection with Helicobacter pylori (H. pylori), may over time evolve into gastric malignancy. Besides H. pylori, high salt intake may play a role in GA development. This study evaluates cross sectionally the association between salt intake and GA in Chilean adults. METHODS: Population-based samples were recruited from two sites, Antofagasta and Valdivia, partaking in the Epidemiological Investigation of Gastric Malignancies. At recruitment, participants answered questionnaires and provided biospecimens. Salt intake (g/day) was estimated from casual spot urine samples using the Tanaka equation. GA was determined by serum pepsinogen levels. Only participants ≥ 40 to 70 years of age were considered in this analysis, n = 565. For the association between salt intake (as sex-specific quartiles) and GA, odds ratios (ORs) and the corresponding 95% confidence intervals (CI) were estimated through multivariable logistic regression. RESULTS: In women, the multivariable-adjusted OR for GA comparing quartile 4 of the estimated salt intake (12.8 g/day) to quartile 1 (6.6 g/day) was 1.18 (95% CI 0.52-2.68, P-trend = 0.87). The corresponding OR in men was 0.49 (95% CI 0.19-1.27, P-trend = 0.17) with salt intakes of 12.8 g/day and 7.1 g/day for quartiles 4 and 1, respectively. CONCLUSION: There was little evidence for an association between salt intake estimated from spot urine and GA risk in our cross-sectional analysis of middle aged and older adults in Chile. Reverse causation bias cannot be ruled out and the sample size was limited to provide more precise estimates.

Regional variations in Helicobacter pylori infection, gastric atrophy and gastric cancer risk: The ENIGMA study in Chile.

BACKGROUND: Regional variations in gastric cancer incidence are not explained by prevalence of Helicobacter pylori, the main cause of the disease, with several areas presenting high H. pylori prevalence but low gastric cancer incidence. The IARC worldwide H. pylori prevalence surveys (ENIGMA) aim at systematically describing age and sex-specific prevalence of H. pylori infection around the world and generating hypotheses to explain regional variations in gastric cancer risk. METHODS: We selected age- and sex-stratified population samples in two areas with different gastric cancer incidence and mortality in Chile: Antofagasta (lower rate) and Valdivia (higher rate). Participants were 1-69 years old and provided interviews and blood for anti-H. pylori antibodies (IgG, VacA, CagA, others) and atrophy biomarkers (pepsinogens). RESULTS: H. pylori seroprevalence (Age-standardized to world population) and antibodies against CagA and VacA were similar in both sites. H. pylori seroprevalence was 20% among children <10 years old, 40% among 10-19 year olds, 60% in the 20-29 year olds and close to or above 80% in those 30+ years. The comparison of the prevalence of known and potential H. pylori cofactors in gastric carcinogenesis between the high and the low risk area showed that consumption of chili products was significantly higher in Valdivia and daily non-green vegetable consumption was more common in Antofagasta. Pepsinogen levels suggestive of gastric atrophy were significantly more common and occurred at earlier ages in Valdivia, the higher risk area. In a multivariate model combining both study sites, age, chili consumption and CagA were the main risk factors for gastric atrophy. CONCLUSIONS: The prevalence of H. pylori infection and its virulence factors was similar in the high and the low risk area, but atrophy was more common and occurred at younger ages in the higher risk area. Dietary factors could partly explain higher rates of atrophy and gastric cancer in Valdivia. IMPACT: The ENIGMA study in Chile contributes to better understanding regional variations in gastric cancer incidence and provides essential information for public health interventions.

Effect of intermittent hypoxia on the reproduction of rats exposed to high altitude in the Chilean Altiplano.

Environmental parameters such as the large day-night temperature differences, high light radiation, and low humidity may have a synergistic effect with low oxygen pressure. To evaluate the effects of the exposure to intermittent chronic hypobaric hypoxia (ICHH) in nature on rat reproduction, a group of rats was alternately moved to a location at 3400 meters over sea level (moml) for 7 days and returned the subsequent week to sea level; this procedure was repeated six times. Hematological and reproductive parameters were measured and analyzed. At the end of the experimental protocol, hematocrit and hemoglobin concentrations were significantly greater in the ICHH group compared to the control group (Nx) (p < 0.05). The diameter of the seminiferous tubule and the height of the spermatogenic epithelium in ICHH rats presented a significant decrease in relation to Nx rats (p < 0.05). Consequently, the number of epididymal spermatozoa in the experimental animals decreased compared to normal rats, with no evidence of recovery after 84 days. The offspring of the different matings between normal and hypoxic animals decreased proportionally to hypoxia exposure. The low oxygen and the changes in testicular temperature homeostasis would provide a novel local mechanism to explain the decrease in sperm cell production and the reduced number of puppies born. The alterations of the reproductive parameters of the hypoxic female, plus testicular injuries and diminished sperm in males, result in a significant decrease in the reproductive activity of the animals.