[Helicobacter pylori infection and gastric cancer in Mexico. A challenge for prevention and population control]. / Infección por Helicobacter pylori y cáncer gástrico en México. Un reto para la prevención y el control poblacional.

The International Agency for Research on Cancer (IARC) of the WHO has recognized a cause-effect relationship between Helicobacter pylori (Hp) infection and gastric cancer of such magnitude that the presence of this infection increases the risk of gastric cancer approximately four times. Gastric cancer is currently the second cause of mortality due to malignant neoplasms in Mexico City. This article explores the association between Hp infection and gastric cancer incidence through an epidemiological study including 109 gastric cancer patients and 177 hospital controls in Mexico City. The study estimates that, in the population studied, Hp infection was present in 87.2% of the cases, compared with 82.5% of the controls. The odds ratio of having gastric cancer if infected with Hp was 1.44 IC95% 0.7-2.8. In addition, it was calculated that with eradication of Hp infection in the general population, gastric cancer incidence would decrease by at least 26.6%. An improvement of the actual sanitary conditions along with the development of an effective vaccine for Hp infection and the existence of increasingly effective treatments to eradicate the bacteria are the necessary next step for populational prevention and control of gastric cancer.

[Diagnostic utility of serum beta-carotenes in intestinal malabsorption syndrome]. / Utilidad diagnóstica de los beta-carotenos séricos en el síndrome de absorción intestinal deficiente.

In order to determine the reference values of serum beta-carotene and its usefulness in the diagnosis of steatorrhea, 140 healthy subjects and 120 patients with suspected malabsorption syndrome were studied. The reference values, established in terms of the percentiles 2.5 and 97.5, were 85-270 micrograms/dL for men and 112-385 micrograms/dL for women. The beta-carotene diagnostic usefulness was determined by comparison with stool fat levels. According to ROC curves, steatorrhea was diagnosed at beta-carotene values of less than 89 micrograms/dL and 103 micrograms/dL for men and women respectively with a 78% sensitivity, 82% specificity, 76% positive and 84% negative predictive values and 80% accuracy. The steatorrhea prevalence (stool fat > 5 g/day) in our patients was 42%. Due to the implicit technical difficulties of the stool fat determinations and the results of this study, we propose the serum quantification of beta-carotene as an useful screening test in patients with chronic diarrhea and malabsorption syndromes.