Dietary inflammatory potential and depression in middle-aged and older adults: A population-based study of...

The relationship between dietary inflammatory potential and depression in middle-aged and older populations has not been fully elucidated. This study aimed to examine this association and its potential mechanisms.

Data from 194,246 UK Biobank participants without depression at baseline were analyzed. The Dietary Inflammatory Index (DII) was used to classify diets as anti-inflammatory (DII < 0) or pro-inflammatory (DII ≥ 0). During a median follow-up time of 11.52 years, 5937 participants developed depression. Cox proportional-hazards models were used to estimate the association in terms of hazard ratio (HR) and 95 % confidence interval (CI). Mediation analyses were conducted to examine the role of inflammation-related indicators and chronic diseases, while disease correlation network analysis was used to explore the relationships between chronic diseases and depression.

A pro-inflammatory diet was associated with an increased depression risk (hazard ratio [HR] = 1.099, 95 % CI: 1.043-1.158). Stratified analyses showed stronger associations in females, participants younger than 60 years at baseline, non-smokers, current smokers, non-drinkers, current drinkers, and those with moderate or high levels of physical activity. Mediation analysis revealed that the neutrophil to high-density lipoprotein cholesterol ratio and obesity mediated 13.69 % and 5.94 % of the relationship, respectively. Disease network analysis highlighted the central role of diabetes and hypertension, with obesity most strongly linked to depression.

This study suggests that adopting an anti-inflammatory diet may help prevent depression in middle-aged and older adults. Inflammation-related indicators and chronic disease partially mediated the association between dietary inflammatory potential and depression.