Association between dietary inflammatory index and the risk of postpartum depression in China

Postpartum depression (PPD) affects numerous women globally, impairing maternal and infant health and contributing to substantial socioeconomic burdens on both families and society. This study aimed to investigate the association between the Dietary Inflammatory Index (DII) and PPD in Chinese women, and explore whether inflammatory cytokines mediate this association.

The study recruited 2038 participants and collected data from them. The Chinese version of the Self-Rating Depression Scale was used to assess postpartum depressive symptoms, and the DII scores were evaluated using semi-quantitative food frequency questionnaires (FFQ). To ensure balanced groups, researchers performed propensity score matching. From the matched participants, 126 blood samples were collected to determine serum levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. Researchers used logistic regression to estimate the odds ratios (OR) and 95 % confidence intervals (CI) between the DII tertiles, inflammatory markers, and PPD. Finally, researchers conducted a mediation analysis using the bootstrap method to examine the relationship between DII, inflammation, and PPD.

Among 2038 participants, 742 (36.4 %) participants were identified as having PPD symptoms. The higher DII scores were associated with PPD, and its significance still exists after a series of factors were adjusted (T2 vs T1: OR = 1.24, 95 % CI: 0.99, 1.55, P > 0.05; T3 vs T1: OR = 1.33, 95 % CI: 1.06, 1.66, P < 0.05). In addition, a higher level of CRP was associated with increased odds of PPD (OR = 1.34, 95 % CI: 1.13, 1.59, P < 0.05). The mediation analysis showed that a direct effect of DII on PPD persisted, and CRP mediated the relationship between DII and PPD.

A higher DII was associated with an increased risk of PPD in Chinese women. The present finding reinforces the importance of limiting pro-inflammatory food consumed and adopting an anti-inflammatory diet to decrease the risk of PPD.