Journal of Inflammation Research (Sep 2021)
Circulating Inflammation Markers Partly Explain the Link Between the Dietary Inflammatory Index and Depressive Symptoms
Abstract
Alessandro Gialluisi,1 Federica Santonastaso,2 Marialaura Bonaccio,1 Francesca Bracone,1 Nitin Shivappa,3,4 James R Hebert,3,4 Chiara Cerletti,1 Maria Benedetta Donati,1 Giovanni de Gaetano,1 Licia Iacoviello1,2 On behalf of the Moli-sani Investigators1Department of Epidemiology and Prevention, IRCCS Neuromed, Pozzilli, Italy; 2Department of Medicine and Surgery, University of Insubria, Varese, Italy; 3Cancer Prevention and Control Program and Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA; 4Department of Nutrition, Connecting Health Innovations LLC, Columbia, SC, USACorrespondence: Alessandro GialluisiDepartment of Epidemiology and Prevention, IRCCS Neuromed, Via dell´Elettronica, 86077, Pozzilli, ItalyTel +390865915244Email [email protected]: Depression is a mood disorder characterized by a high rate of resistance to pharmacological treatments, which has often been linked to chronic inflammation. This can be influenced by different environmental factors, in particular pro-inflammatory diets. However, a mediating role of circulating inflammation has never been observed.Aim: To test the association between a dietary inflammatory index (DII®) and continuous depressive symptoms (adapted version of PHQ9) in an Italian population cohort (N=13,301), along with potential explanatory effect of a composite index (INFLA-score) based on four circulating inflammatory biomarkers: C-reactive protein, granulocyte-to-lymphocyte ratio, platelet and white blood cell counts.Results: Significant positive associations were observed between DII and total depressive symptoms (standardized β (SE) = 0.038 (0.005), p < 0.001), and with two factors tagging somatic (0.012 (0.003), p < 0.001) and cognitive symptoms (0.012 (0.003), p < 0.001), after adjustment for different potential confounders (socioeconomic status, chronic health conditions and lifestyles). These associations were about twice as strong in women than in men. INFLA-score explained a small but significant proportion of the association with total depressive symptoms (0.90– 2.30%, p < 0.05), which was mainly driven by granulocyte-to-lymphocyte ratio (1.18– 1.65%). This effect was even stronger for the somatic (2.66– 4.66%) but not for the cognitive factor (0%).Conclusion: These findings support a strong link between inflammatory diet and depression, especially with somatic symptoms and within women. Moreover, they provide novel evidence for a potential explanatory role of circulating inflammation in this association, suggesting new paths for prevention and treatment of major and atypical depression.Keywords: dietary inflammatory index, depressive symptoms, atypical depression, circulating inflammation, granulocyte-to-lymphocyte ratio, white blood cells