Relationship between diet quality and depression among Iranian older adults in Tehran

BACKGROUND: Depression is one of the prevalent mental disorders that is common in older ages. Evidence suggests that dietary intake status may potentially be associated with depression. However, this association has not been well studied in older adults, and the nature of the association remains unclear. This study aimed to investigate the association between diet quality and depression in free-living older adults living in Tehran city. METHODS: This cross-sectional study was conducted on 583 older adults (279 men and 304 women) aged 60 to 80 years living in Tehran city, selected by the systematic cluster sampling method. Individuals' dietary intake was determined by two non-consecutive 24-h dietary recalls, and diet quality was assessed calculating score of Healthy Eating Index-2015 (HEI-2015). The validated short form of the Geriatric Depression Scale (GDS-11) was used to assess depression status. A logistic regression model was used to assess the chance of depression across tertiles of HEI-2015 score. RESULTS: The point prevalence of depression was 22.5%, which was significantly higher in women (91 (69.5%) women vs. 40 (30.5%) men). A higher percentage of seniors at the higher tertile of HEI score were women, belonged to Fars ethnicity and had a higher score of activity of daily living (ADL). After adjustment for all potential confounders, the trend of depression chance was significantly decreased in those with higher HEI-2015 scores (p-for trend < 0.05). CONCLUSION: Higher quality of diet was associated with a lower possibility of depression in the studied participants. Further studies are required to investigate the possible causal relationship. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-03380-1.