(LB02-03-24) Associations of Dietary Inflammatory Index, C-reactive Protein and Depression Among Pregnant Women: National Health and Nutrition Examination Survey 2007–2010, 2015–2018

Objectives: About 12% of pregnant women experience depression in second and third trimesters. Previous research shows that inflammation increases during pregnancy, which may impact depression. Inflammation is influenced by various modifiable factors, including diet. Dietary Inflammatory Index (DII) is a validated tool that assesses the inflammatory potential of diet. Higher DII scores (i.e., more pro-inflammatory) are significantly associated with increased levels of inflammatory markers, such as C-reactive protein (CRP). No study to date has assessed the association of DII with depression during pregnancy or the mediation effect of CRP on this association.

Methods: We limited our analysis to adults above the age of 20 y in the National Health and Nutrition Examination Survey (NHANES). Pregnancy was confirmed via pregnancy tests. DII was distributed normally (mean = 0.17 ± 1.75). Depression was assessed using the 9-item Patient Health Questionnaire (PHQ-9). The PHQ-9 score range in our sample was 0-17. We dichotomized depression into no-to-minimal depression (PHQ-9 < 5) and mild-to-moderately severe depression (PHQ-9 ≥ 5). We dichotomized CRP by the cut-off of 3 mg/L. Logistic regression models were used to examine the association of DII with CRP and depression. We adjusted our model for age, race/ethnicity, BMI, marital status, education, smoking, physical activity, poverty-to-income ratio, and parity. We used structural equation modeling to assess the mediation of log-transformed continuous CRP levels on the association of DII and continuous depression score.

Results: Our final sample included 125 pregnant women (mean age = 29.3 ± 5.9). For each unit increase in DII, the likelihood of mild-to-moderately severe depression increased by 32% (95% CI 1.02-1.71; P=0.03). However, we did not find any significant associations between DII and CRP (OR=1.25; 95% CI 0.94-1.67, P=0.11). The association of DII and depression was not significantly mediated by CRP.

Conclusions: A pro-inflammatory diet significantly increases likelihood of depression in pregnant women. This association was not mediated by CRP. As CRP is a non-specific marker of inflammation, future research should focus on examining the mediation effect of other inflammatory markers, such as cytokines.

Funding Sources: None