Dietary phytochemical index in relation to risk of glioma: a case-control study in Iranian adults

Somaye Rigi,Seyed Mohammad Mousavi,Ahmad Esmaillzadeh,Mehdi Shayanfar,Giuve Sharifi,Minoo Mohammad-Shirazi

doi:10.1186/s12937-021-00689-2

Abstract

Background & aimNo study is available that explores the association of dietary phytochemical index (DPI) with glioma. The objective of the current study was to assess this association in Iranian adults.MethodsThis hospital-based case-control study included 128 newly-diagnosed cases of glioma and 256 age- and sex-matched controls. Data collection on dietary intakes was done using a 123-item validated food frequency questionnaire. Calculation of DPI was done as (dietary energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Logistic regression models were used to examine the association between DPI and glioma.ResultsIndividuals in the top tertile of DPI were more likely to be older and female. Before taking potential confounders into account, subjects in the top tertile of DPI tended to have a 40% reduced chance of glioma than those in the bottom tertile (OR: 0.60; 95% CI: 0.35–1.02, P = 0.06). After controlling for age, sex, energy intake, several demographic variables and dietary intakes, the association between DPI and glioma became strengthened (OR: 0.43; 95% CI: 0.19–0.97, P = 0.04).ConclusionHigh intakes of phytochemical-rich foods were associated with a lower risk of glioma in adults. High consumption of phytochemical-rich foods might be recommended to prevent glioma. However, further studies with a prospective design are needed to confirm our findings.

Highlights

Background & aimNo study is available that explores the association of dietary phytochemical index (DPI) with glioma
The phytochemical-rich foods we considered in the current study were as follows: Whole grains (Sangak and Barbari bread, which are traditional Iranian breads); fruits; vegetables; soy products; nuts; legumes; olives; olive oil; natural fruit and vegetable juices
After controlling for age, sex, energy intake, several demographic variables and dietary intakes, the association between DPI and glioma became strengthened (OR: 0.43; 95% CI: 0.19–0.97, P = 0.04)

Summary

Introduction

Background & aimNo study is available that explores the association of dietary phytochemical index (DPI) with glioma. Epidemiologic studies on some food groups, including fresh fruits, vegetables, nuts and legumes in relation to glioma, have yielded protective associations [11,12,13]. These plant-based foods are rich in antioxidants, fiber and phytochemicals [14]. Considering the inverse association between phytochemical-rich foods with glioma in earlier studies [26,27,28], we hypothesized that DPI might be associated with brain tumors. We aimed to assess DPI in relation to the risk of glioma in the framework of a casecontrol study in Iranian adults

Objectives

Methods

Results

Discussion

Conclusion