Characteristics of spicy food consumption and its association with depressive symptoms in Sichuan and Qingdao populations: evidence from China Kadoorie Biobank (CKB)

Abstract Background Depression is a leading cause of global disability, projected to become the foremost contributor to disease burden by 2030. In China, its prevalence has risen steadily, posing a major public health challenge. Evidence on the association between spicy food consumption and depressive symptoms remains inconsistent, with few studies considering regional dietary cultural differences. Methods This cross-sectional study analyzed baseline data from 86,542 participants in Sichuan and Qingdao from the China Kadoorie Biobank (CKB). Spicy food consumption was assessed across frequency, intensity, and cumulative burden. Depressive symptoms were evaluated using a four-item screening measure; participants reporting any item were classified as having depressive symptoms. Multivariable logistic regression was used to assess cross-sectional associations, and K-means clustering was used to identify consumption patterns. Results Marked regional differences were observed. In Sichuan, daily consumption (68.74% vs. 5.65% in Qingdao) and higher cumulative burden were prevalent. After full adjustment, higher frequency, intensity, and burden were cross-sectionally associated with lower odds of depressive symptoms overall and in Sichuan (e.g., daily: aOR = 0.733, 95% CI : 0.586–0.917). In Qingdao, only moderate-frequency consumption (3–5 days/week) showed an inverse association (aOR = 0.324, 95% CI : 0.132–0.797). Cluster analysis identified three patterns: Occasional Moderate, Intermediate Mild, and Frequent Intense Consumers. Only Frequent Intense Consumers (predominantly in Sichuan) showed a significant inverse association with depressive symptoms (aOR = 0.803, 95% CI : 0.672–0.959). Conclusion This cross-sectional study suggests the association between spicy food consumption and depressive symptoms may be context-dependent, shaped by regional dietary culture. In Sichuan, habitual intense consumption was associated with lower odds of depressive symptoms; in Qingdao, only moderate-frequency intake showed an inverse association. These findings suggest that culturally tailored dietary approaches warrant further investigation for mental health promotion.