Environmental factors related to gastric cancer associated with Epstein-Barr virus in Colombia.

Epstein-Barr virus (EBV)-encoded small RNA can be detected in about 1-17 % of gastric carcinomas. To elucidate lifestyles and other factors related to such an EBV-associated gastric carcinoma (EBV-GC), we conducted a case-control study in Cali, Colombia. The study subjects were 368 patients with gastric carcinoma newly diagnosed during the period between September 2000 and June 2003, including 42 EBV-GC cases. We obtained information on lifestyles, dietary habits, and occupational exposure by a questionnaire. The frequency of EBV-GC was related to birth order of patients (P for trend =0.025). More precisely, EBV-GC was much less frequent among the patients who were the eldest child in a family (P=0.007). Those findings were contrary to what was reported by the study conducted in Japan, where EBV-GC was more frequently observed among eldest brothers/sisters. A possible explanation for the apparently conflicting results is that EBV-GC risk is related to the age at first EBV infection but its relationship is not monotonic. In addition to the relationship with birth order, the present study showed that high salt intake and metal dust exposure may be related to EBV-GC as reported by the Japanese study although these associations observed in the present study were not statistically significant. No significant association was observed in other factors, including dietary habits. Further studies seem warranted to elucidate the difference between Japan and Colombia with respect to the environmental factors related to EBV-GC cases.

Toenail zinc level and gastric cancer risk in Cali, Colombia.

PURPOSE: To examine the associations between gastric cancer (GC) risk and the zinc levels in toenail clippings, we conducted a hospital-based case-control study during the period from 2000 to 2002 in Cali, Colombia. METHODS: Toenail clippings and information on lifestyles including dietary habits were obtained from 156 GC patients newly diagnosed in three hospitals in Cali and 287 controls selected from non-cancer patients who were hospitalized in the same hospitals as GC patients. Zinc concentrations in toenail clippings were examined using inductively coupled plasma mass spectrometry. RESULTS: An inverse association was observed between toenail zinc level and GC risk (P for trend = 0.039). When we examined this association separately for current and former smokers and non-smokers, only current-smokers showed a significant inverse association (P for trend = 0.035). Histology specific analysis revealed that this inverse association was stronger when we limited GC cases with intestinal-type and their matched controls (P for trend < 0.001). This association was also observed in the carcinomas located in the upper two-thirds of the stomach (P for trend = 0.004) but not in carcinomas in the lower-third of the stomach (P for trend = 0.727). CONCLUSIONS: There was an inverse association between toenail zinc level and GC risk. However, the association was limited to smokers, intestinal-type GC, and tumors in the upper two-thirds of the stomach. Further studies seem warranted to confirm our findings.