The association between index of nutritional quality (INQ) and gastric cancer and evaluation of nutrient intakes of gastric cancer patients: A case-control study

Background: Gastric cancer (GC) is the fourth major malignancy and the second leading cause of cancer-related deaths worldwide. Northern and northwestern areas of Iran are among the high risk areas for GC. Studies have shown that dietary components are implicated in the etiology of GC. The index of nutritional quality (INQ) is a method of quantitative and qualitative analysis of single foods, meals, and diets. We aimed to assess the association of INQ with GC, and to evaluate the nutrient intake of GC patients. Methods: The present case-control study included 82 cases and 95 healthy controls attending specialized centers in Tabriz, Iran, from December 2014 to May 2016. INQ scores were computed based on dietary intake assessed using a validated 168-item food frequency questionnaire (FFQ). Logistic regression models were used to estimate multivariable ORs adjusted age, gender, Body Mass Index (BMI), smoking, residency, education, and regular physical activity. Results: After controlling for several covariates, inverse associations were observed between GC risk and INQs of vitamins A, B6, and D (ORvitA = 0.25 (0.06 - 0.98); ORvitB6 = 0.10 (0.04 - 0.28); and ORvitD = 0.14 (0.02 - 0.84)). Cases had higher intake of total fat, saturated fatty acids, beef, lamb meat, salt, and paprika compared to controls. On the other hand, controls had higher intake of vitamin A, vitamin, vitamin B6, copper, poultry, low fat milk, tea, coffee, turmeric, and saffron compared to cases. Conclusions: Subjects who follow a more healthy and nutrient-rich diet, especially in terms of vitamins A, B6, and D, are at lower risk of having GC, compared to those who consume a more unhealthy, nutrient-poor diet.