Salt intake and gastric cancer: a pooled analysis within the Stomach cancer Pooling (StoP) Project

Purpose: Previous studies show that consuming foods preserved by salting increases the risk of gastric cancer, while results on the association between total salt or added salt and gastric cancer are less consistent and vary with the exposure considered. This study aimed to quantify the association between dietary salt exposure and gastric cancer, using an individual participant data meta-analysis of studies participating in the Stomach cancer Pooling (StoP) Project. Methods: Data from 25 studies (10,283 cases and 24,643 controls) from the StoP Project with information on salt taste preference (tasteless, normal, salty), use of table salt (never, sometimes, always), total sodium intake (tertiles of grams/day), and high-salt and salt-preserved foods intake (tertiles of grams/day) were used. A two-stage approach based on random-effects models was used to pool study-specific adjusted (sex, age, and gastric cancer risk factors) odds ratios (aORs), and the corresponding 95% confidence intervals (95% CI). Results: Gastric cancer risk was higher for salty taste preference (aOR 1.59, 95% CI 1.25–2.03), always using table salt (aOR 1.33, 95% CI 1.16–1.54), and for the highest tertile of high-salt and salt-preserved foods intake (aOR 1.24, 95% CI 1.01–1.51) vs. the lowest tertile. No significant association was observed for the highest vs. the lowest tertile of total sodium intake (aOR 1.08, 95% CI 0.82–1.43). The results obtained were consistent across anatomic sites, strata of Helicobacter pylori infection, and sociodemographic, lifestyle and study characteristics. Conclusion: Salty taste preference, always using table salt, and a greater high-salt and salt-preserved foods intake increased the risk of gastric cancer, though the association was less robust with total sodium intake. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.This study was funded by national funds from the Foundation for Science and Technology—FCT (Portuguese Ministry of Science, Technology and Higher Education), under the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit; UIDB/04750/2020), by the Associazione Italiana per la Ricerca sul Cancro (AIRC), Project no. 21378 (Investigator Grant), and the Agency for Management of University and Research Grants (AGAUR) of the Catalan Government (Grant 2017SGR723). AC and SM were funded under the scope of the project "NEON-PC—Neuro-oncological complications of prostate cancer: longitudinal study of cognitive decline" (POCI-01-0145-FEDER-032358; ref. PTDC/SAU-EPI/32358/2017). SM was also funded under EPIUnit—Junior Research—Prog Financing (UIDP/04750/2020). An individual grant attributed to NA (SFRH/BD/119390/2016) was funded by FCT and the ‘Programa Operacional Capital Humano’ (POCH/FSE). The authors thank the European Cancer Prevention (ECP) Organization for providing support for the project meetings, all MCC-Spain study collaborators (CIBERESP, ISCIII, ISGlobal, ICO, University of Huelva, University of Oviedo, University of Cantabria, University of León, ibs. Granada, Instituto Salud Pública de Navarra, FISABIO, Murcia Regional Health Authority and cols). The funding sources had no role in the study design; collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication