Dietary habits, nutrition and esophageal cancer: A case-control study on Kazakhs in Xinjiang

Abstract

Objective

To explore associations between dietary habits and esophageal epithelial cell carcinoma (ESCC) and provide a potential direction for exploring how different dietary habits and nutrient intake might affect ESCC development.

Methods

198 ESCC cases and 200 controls on Kazakhs were recruited in Xinjiang from 2010 to 2019 for a group-matched case-control study. The case group were recruited from the First Affiliated Hospital of Xinjiang Medical University and Affiliated Cancer Hospital of Xinjiang Medical University. The control population were recruited from two parts: hospital-based control and population-based control. The diagnosis was confirmed by histological examination. The food frequency questionnaire was used to investigate the dietary nutrients intake. Folic acid, vitamin B12, and DNA-methyltransferase 1(DNMT1) levels were measured in serum samples obtained from cases and controls.

Results

The cholesterol intake of ESCC group was significantly higher than that of the control group while the intakes of protein, thiamin, riboflavin, folic acid, vitamin A, B6, C and E were significantly lower than the control group. Factors including lacking fresh vegetables and fruits, low educational level, low income, alcohol drinking, eating solid and dry food and smoked meat, dieting irregularly, salty taste preference, low serum folic acid level and high serum DNMT1 level were associated with increased risk of ESCC in Kazakhs.

Conclusion

Dietary habits and nutrient intake were associated with increased risk of ESCC in Kazakhs that may provide a potential direction for further studies.

Highlights

• • A group-matched case-control design was used in this study on Kazakhs in Xinjiang from 2010 to 2019.
• • Dietary habits and nutrient intake were associated with increased risk of ESCC in Kazakhs
  

  1 Introduction

  Esophageal cancer (EC) is one of the most common malignant tumors in the world, which seriously threatens people’s physical and mental health. About 291,000 people are diagnosed with esophageal cancer each year in China. And there is the high incidence rate of 11.28/100,000 and the high mortality rate of 8.36/100,000 reported by the China Cancer Registry, which ranks sixth and fourth place in malignant tumors [1] . The incidence of esophageal epithelial cell carcinoma (ESCC) varies among different regions, and significant geographical distribution is the prominent epidemiological feature of ESCC [2] . Compared with other ethnic groups in China, Kazakhs who normally inhabited in Xinjiang have the highest incidence for ESCC [3] , with an age-adjusted mortality rate of 68.88/100,000. Many Kazakhs depend on stock farming and live in a unique geographical environment and keep long-standing lifestyle and dietary habits, such as smoking, alcohol drinking, alcohol drinking hot milk tea, and eating smoked meat while eating few fresh vegetables and fruits [4] .

  Inadequate intake of vegetables and fruits is likely to cause the deficiency of folic acid. Folic acid is a water-soluble B-vitamin that is mainly identified in citrus fruits, green leafy vegetables, beans, grains and animal livers 567 , which plays an essential role in the maintenance of body’s function. Lacking Vitamin B12, which is a coenzyme synthesized by methionine, can affect methionine synthesis and further undermine DNA methylation and regeneration of THF, eventually causing the relative shortage of folic acid [8] .

  Interestingly, lacking of folic acid are negatively correlated with DNA-methyltransferase 1(DNMT1) as shown by many studies. DNMT1 is an enzyme that in humans in encoded by the DNMT1 gene. DNA- methyltransferases (DNMTs) mainly regulate the process of DNA methylation that is an important form of the base modification in genomes, as well as catalyze the combination between methyl groups and cytosine rings [9] .

  The aim of this study is to examine associations between dietary habits and esophageal cancer risk and provide a potential direction for further studies. Therefore, we carried out a group-matched case-control study in order to understand the relationship among dietary habits, nutrient intake and ESCC.