Dietary phytochemical index and attention-deficit/hyperactivity disorder in Iranian children: a case control study

Abstract

OBJECTIVE: Attention Deficit/Hyperactivity Disorder (ADHD) is a common behavioral disorder among children. Based on literature, it has been hypothesized that the higher intake of rich sources of phytochemicals may be inversely related to the risk of ADHD. We investigated the association of dietary phytochemical index (DPI) with odds of ADHD. METHODS: This case-control study was conducted on 360 children and adolescents 7-13 years old in Yazd, Iran. Subjects were categorized into the case (n = 120) and control groups (n = 240) based on matching age and sex. To diagnose ADHD, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSMIV-TR) was used. Food frequency questionnaire was used to measure food intake. DPI was calculated by percent of daily energy intake from phytochemical-rich foods. The association of DPI with the odds ratio of ADHD was examined by logistic regression. RESULTS: Subjects in the highest quartile of DPI have higher intake of macronutrient, eicosatetraenoic acid, docosahexaenoic acid, calcium, zinc, iron, vitamins B12, B6, and folic acid compared to lowest quartile. After adjusting for potential confounders, subjects in the highest quartile of DPI compared with subjects in the lowest quartile showed a lower risk of ADHD (OR: 0.44; 95 CI: 0.18-0.90). There was a significant decreasing trend in the odds of ADHD across increasing quartile of DPI (P for trend: 0.02). CONCLUSION: We found that higher DPI score is associated with lower risk of ADHD in children. Cohort and clinical studies are necessary to approve our results.