Dados do Resumo

Título

Calcium intake and gastric cancer: A systematic review

Introdução

Gastric cancer was the fifth most common type and cause of mortality globally in 2022. Diet, particularly calcium intake, plays a key role in its development. Research shows calcium's effects on gastric carcinogenesis can be both protective and harmful, depending on biological contexts. Calcium is vital for skeletal integrity and cell regulation, impacting cancer development. The role of calcium in gastric carcinogenesis is intricate and influenced by multiple factors, including H. pylori infection, gastric acid secretion, and individual genetic susceptibility, with mixed evidence on its influence on cancer risk.

Objetivo

The aim of this systematic review was to assess the relationship between calcium intake and gastric cancer by synthesizing evidence from observational studies, including cohort and case-control studies.

Métodos

This systematic review, registered in PROSPERO (CRD42024550664), was conducted according to the latest PRISMA guidelines. A comprehensive search was performed by two reviewers across PubMed, Scopus, EMBASE, LILACS, and Web of Science up to August 19, 2024, using MeSH terms, keywords, and synonyms tailored to each database. Titles and abstracts were screened by two independent reviewers based on PECOS criteria. References from original reports and previous reviews were also manually checked. The search included only human studies and had no language restrictions. Studies involving calcium consumption through dietary or supplements, assessed via validated questionnaires, were included. Exclusion criteria were cross-sectional studies, editorials, case reports, reviews, ecological studies, monographs, and animal studies. Duplicates were removed. Data were extracted independently, including the first author's name, publication year, country, study design, sample size, age, dietary assessment, exposure, and key takeaways. Study quality was evaluated using the Newcastle–Ottawa Scale (NOS). Any disputes were resolved by consulting a third author.

Resultados

A total of 6,992 studies were found, with 2,125 duplicates, leaving 4,867 studies. One study found outside the databases led to 15 studies eligible for full-text review. After review, two studies were excluded, leaving 13 eligible for the systematic review. These studies, published between 1988 and 2024, included 6,172 gastric cancer cases among 1,530,255 participants aged 30 to 80. They included four cohort studies and nine case-control studies. These studies were conducted in populations of Europe (6), Asia (4) and North American (3). One study assessed both supplementation and dietary calcium, one focused on supplementation, and the rest on dietary calcium. Three case-control studies conducted in Asian populations found a significant link between high dietary calcium and a lower risk of gastric cancer.

Conclusões

This is the first systematic review that brought together evidence on dietary calcium consumption and the risk of gastric cancer, suggesting a potential protective effect of this mineral. It is important to highlight that the conclusions were limited in Asian populations, and no study was conducted in Latin American populations, including Brazi. Further studies with another type of design and other populations are needed to confirm these findings.

Financiador do resumo

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.

Palavras Chave

Dietary calcium; Stomach cancer