Dados do Trabalho

Título

Polyphenol intake and gastric cancer: a case-control study in the Brazilian Amazon region

Introdução

Gastric cancer (GC) is the fifth most common type of cancer and remains a public health concern worldwide. In Brazil, the geographical regions show disparities in the incidence and mortality rates for GC, probably due to a variety of risk factors. Accumulating evidence indicates that polyphenols have important biological properties, which are associated with decreased risk of some types of cancer, including GC. However, few studies address this topic in the Latin American population.

Objetivo

This pioneering case-control study aimed to evaluate the association between GC and the dietary intake of the main polyphenol classes and subclasses in the Brazilian Amazon region.

Métodos

A case-control study was conducted in Belém (Amazon region) from July 2017 to February 2021. A total of 193 GC cases and 194 controls of both sexes, between 18 and 75 years old, were included in the study. Cases and controls were matched by frequency and according to sex and age in 5-year groups. Dietary data were collected using a validated food-frequency questionnaire and polyphenol intake identified using the Phenol-Explorer database. Odds ratios and 95% confidence intervals for gastric cancer were calculated across the tertiles of dietary polyphenols using logistic regression after controlling for known risk factors. The lowest tertile of each dietary polyphenol subclass was used as the reference. Summary results were reported as risk rather than probability for simplicity’s sake, in line with similar case-control studies. All statistical analyses were conducted using the software SPSS Statistics for Windows, Version 25.0.

Resultados

Cases and controls had similar total polyphenol intake (356.4 mg/1000kcal/d and 331.1 mg/1000kcal/d, respectively; p=0.086). After adjusting for potential confounders, high consumption of flavan-3-ols (highest vs. lowest tertile: OR 0.41, 95%CI 0.18-0.94) and hydroxybenzoic acids (highest vs. lowest tertile: OR 0.24, 95%CI 0.10-0.56) was associated with a decreased risk of GC. The opposite was true regarding the intake of flavones (OR 2.46, 95%CI 1.17-5.18) and other polyphenols (OR 2.54, 95%CI 1.16-5.54). When stratifying according to anatomical topography, we observed that the intake of total flavonoids, flavan-3-ols, and flavanones reduced the risk of cardia GC while that of hydroxybenzoic acids reduced the risk of non-cardia GC. According to histologic subtypes, hydroxybenzoic acid intake was associated with a reduced risk of intestinal-type GC (OR 0.21, 95%CI 0.07-0.64), while flavone consumption was associated with an increased risk of diffuse-type GC (OR 2.59, 95%CI 1.05-6.42).

Conclusões

Our findings suggest that in the Brazilian Amazon region the high intake of total flavonoids, flavan-3-ols, flavanones, and hydroxybenzoic acids is associated with a reduced risk of GC, suggesting a potential beneficial role of these compounds against GC. A valid strategy to reduce the risk of gastric cancer is an increase in the consumption of foods rich in polyphenols, such as tea and fruits like açai, papaya, grapes, and oranges.

Palavras-chave

Gastric cancer, diet, polyphenol intake, case-control study, Brazil.

Financiador do resumo

This research received funding from the São Paulo Research Foundation (FAPESP) with grant number: 2014/26897-0. In addition, this study was financed in part by the Brazilian National Council for Scientific and Technological Development (CNPq), who provided a fellowship.