Objective:

To investigate the longitudinal associations of the C-reactive protein-triglycerides-glucose (CTI) index and its obesity-related derivatives with incident depression among middle-aged and older adults across CKM stages 0-4.

Key Findings:

• Over a median follow-up of 9 years, 1,275 participants developed depression, indicating a significant incidence rate.
• The CTI-Chinese visceral adiposity index (CTI-CVAI) showed the highest AUC of 0.705, indicating strong predictive value.
• Higher baseline CTI-CVAI was associated with a decreased risk of depression (HR per 1-SD=0.91).
• A linear dose-response relationship was observed for both baseline and cumulative CTI-CVAI.
• Significantly lower depression risks were noted in individuals with high-increasing trajectory and highest cumulative exposure tertile.
• The inverse association was more pronounced in participants aged <60 years.

Interpretation:

CTI-CVAI serves as an independent predictor for incident depression, suggesting that moderate cardiometabolic and nutritional reserves may correlate with better mental health in older adults, particularly in the context of CKM syndrome.

Limitations:

• The study is observational, limiting causal inferences.
• Potential confounding factors, such as socioeconomic status and lifestyle variables, may not be fully accounted for despite multivariable adjustments.

Conclusion:

CTI-CVAI is a promising candidate marker for predicting incident depression in middle-aged and older adults across CKM stages 0-4.