Coffee consumption and risk of gastric cancer: an updated meta-analysis

Background and Objectives: Coffee is one of the most widely consumed beverages worldwide, and many studies have investigated the association between coffee consumption and gastric cancer. However, the results are inconsistent. We conducted a systematic analysis of relevant population studies to derive a more precise estimation. Methods and Study Design: Cochrane library, PubMed and Embase databases were searched to identify studies that met predetermined inclusion criterion through July 2014. All epidemiologic studies regarding coffee consumption and gastric cancer risk were selected, and relative risks (RRs) with 95% confidence intervals (CIs) were calculated. Results: Twenty two studies (9 cohort and 13 case-control studies) involving 7,631 cases and 1,019,693 controls were included. The summary RR of gastric cancer was 0.94 (95% CI: 0.80-1.10) for the highest category of coffee consumption compared with the lowest category, and 0.93 (95% CI: 0.88-0.99) for coffee drinkers compared with nondrinkers. We stratified the population by coffee consumption. The pooled RR for the population with <1 cup/day, 1-2 cups/day and 3-4 cups/day coffee consumption compared with nondrinkers were 0.95 (95% CI: 0.84-1.08), 0.92 (95% CI: 0.82-1.03) and 0.88 (95% CI: 0.76-1.02), respectively, indicating that an increase in coffee consumption was associated with a decreased risk of gastric cancer. Furthermore, we stratified the studies by design, sex, population and time. A significant association between coffee intake and decreased gastric cancer risk was shown in case-control studies (RR=0.85, 95% CI: 0.77-0.95) and among the studies published over the last ten years (RR=0.88, 95% CI: 0.77-1.00). Conclusions: Our meta-analysis suggested that coffee consumption might be associated with a decreased risk of gastric cancer.