Although it appears biologically plausible for iron to be associated with gastric carcinogenesis, the evidence is insufficient to lead to any conclusions. To further investigate the relationship between body iron status and gastric cancer risk, we conducted a nested case-control study in the multicentric European Prospective Investigation into Cancer and Nutrition (EPIC) study. The study included 456 primary incident gastric adenocarcinoma cases and 900 matched controls that occurred during an average of 11 years of follow-up. We measured prediagnostic serum iron, ferritin, transferrin and C-reactive protein, and further estimated total iron-binding capacity (TIBC) and transferrin saturation (TS). Odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of gastric cancer by iron metrics were estimated from multivariable conditional logistic regression models. After adjusting for relevant confounders, we observed a statistically significant inverse association between gastric cancer and ferritin and TS indices (ORlog2  = 0.80, 95% CI = 0.72-0.88; OR10%increment  = 0.87, 95% CI = 0.78-0.97, respectively). These associations appear to be restricted to noncardia gastric cancer (ferritin showed a p for heterogeneity = 0.04 and TS had a p for heterogeneity = 0.02), and no differences were found by histological type. TIBC increased risk of overall gastric cancer (OR50 µg/dl  = 1.13, 95% CI = 1.02-1.2) and also with noncardia gastric cancer (p for heterogeneity = 0.04). Additional analysis suggests that time between blood draw and gastric cancer diagnosis could modify these findings. In conclusion, our results showed a decreased risk of gastric cancer related to higher body iron stores as measured by serum iron and ferritin. Further investigation is needed to clarify the role of iron in gastric carcinogenesis.

General obesity, as reflected by BMI, is an established risk factor for esophageal adenocarcinoma (EAC), a suspected risk factor for gastric cardia adenocarcinoma (GCC) and appears unrelated to gastric non-cardia adenocarcinoma (GNCC). How abdominal obesity, as commonly measured by waist circumference (WC), relates to these cancers remains largely unexplored. Using measured anthropometric data from 391,456 individuals from the European Prospective Investigation into Cancer and Nutrition (EPIC) study and 11 years of follow-up, we comprehensively assessed the association of anthropometric measures with risk of EAC, GCC and GNCC using multivariable proportional hazards regression. One hundred twenty-four incident EAC, 193 GCC and 224 GNCC were accrued. After mutual adjustment, BMI was unrelated to EAC, while WC showed a strong positive association (highest vs. lowest quintile HR = 1.19; 95% CI, 0.63-2.22 and HR = 3.76; 1.72-8.22, respectively). Hip circumference (HC) was inversely related to EAC after controlling for WC, while WC remained positively associated (HR = 0.35; 0.18-0.68, and HR=4.10; 1.94-8.63, respectively). BMI was not associated with GCC or GNCC. WC was related to higher risks of GCC after adjustment for BMI and more strongly after adjustment for HC (highest vs. lowest quintile HR = 1.91; 1.09-3.37, and HR = 2.23; 1.28-3.90, respectively). Our study demonstrates that abdominal, rather than general, obesity is an indisputable risk factor for EAC and also provides evidence for a protective effect of gluteofemoral (subcutaneous) adipose tissue in EAC. Our study further shows that general obesity is not a risk factor for GCC and GNCC, while the role of abdominal obesity in GCC needs further investigation.