Association of the triglyceride-glucose index with risk of depression and anxiety: A prospective cohort study.

Background: The relationship between the triglyceride glucose (TyG) index and depression/anxiety remains unclear. This study prospectively examines whether elevated TyG index increases depression and anxiety risk.

Methods: Our analysis included 383,621 individuals from the UK Biobank who were free of depressive and anxiety disorders at enrollment. TyG index was calculated as ln (fasting triglyceride [mg/dL] × fasting blood glucose [mg/dL]/2). Depression and anxiety symptoms were assessed using primary care data and hospital inpatient records. Multivariable Cox regression analyses evaluated the prospective relationships of TyG index with incident depression and anxiety, with subgroup and sensitivity analyses.

Results: Over a median 13.75-year follow-up, 20,548 depression and 18,418 anxiety cases occurred. Participants with TyG index in the upper quartile had 29 % greater hazards for depression (HR = 1.29, 95 %CI: 1.23, 1.35) and 20 % elevated incidence of anxiety disorders (HR = 1.20, 95 %CI: 1.14, 1.25) when benchmarked against the reference group in the lowest quartile. Each standard deviation increase in TyG index was associated with a 21 % higher incidence of depression and an 15 % higher incidence of anxiety, respectively. Furthermore, these associations were stronger in participants aged <60 years, those with upper secondary or higher education, non-smokers (for anxiety), and ever-drinkers and females (for depression).

Conclusions: TyG index is positively associated with incident depression and anxiety disorders, particularly in young adults, individuals with upper secondary or higher education, non-smokers (regarding anxiety), ever-drinkers and females (regarding depression).