Consumption of processed and pickled food and esophageal cancer risk: A systematic review and meta-analysis

Previous investigations yielded inconsistent results for association of esophageal cancer (EC) risk and intake of processed food (including pickled food) or pickled food alone. The aim of this study was to perform a systematic review and meta-analysis of data exploring association of EC risk and intake of processed food (including pickled food) or pickled food alone. We systematically searched on PubMed and Web of Science for association of EC risk and intake of processed and pickled food published from 1964 to April 2018. We computed the multivariate odd ratio (OR) or relative risk (RR) and 95% confidence intervals (CI), comparing the highest and the lowest categories of processed or pickled food intake. The present meta-analysis showed that the highest categories of processed food intake were associated with a 78% increase in EC risk compared with the lowest categories. In addition, meta-analysis results indicated that the combined OR/RRs (95%CI) of studies comparing the highest and lowest categories were 2.10 (1.64-2.69) for pickled food. Subgroup study indicated significant positive associations between EC risk and intake of processed food or pickled food in case-control studies (combined ORs: processed food: 1.93 (95%CI: 1.66-2.24), pickled food: 2.28 (95%CI: 1.93-2.70)), whereas no significant associations were detected between them in cohort studies (combined RRs: processed food: 1.24 (95%CI: 0.98-1.58), pickled food: 1.43 (95%CI: 0.85-2.42)). In conclusion, this study suggests that both a high consumption of processed and pickled food may increase the EC risk.