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.