Association Between Cognitive Dysfunction, TYG Index, and Depression in Older Adults: Based on the NHANES Database,...

The relationship between cognitive impairment, triglyceride-glucose (TyG) index, and depression in the elderly remains unclear. This study aims to explore the associations among cognitive impairment, TyG index, and the risk of depression in older adults, providing a basis for targeted prevention strategies.

This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Cognitive impairment was defined as the lowest quartile of three cognitive tests: the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test for learning and memory, the Animal Fluency test for executive function, and the Digit Symbol Substitution Test (DSST) for attention and processing speed. The TyG index was calculated as ln[triglycerides (mg/dL) × fasting glucose (mg/dL)/2], and participants were categorized into quartiles based on their TyG index. Multivariable logistic regression models were employed to investigate the relationships between cognitive impairment, TyG index, and depression in the elderly.

A total of 2042 elderly participants (aged ≥ 60 years) were included in the study, among whom 312 (15.3%) were diagnosed with depression. Both cognitive impairment and higher TyG index were significantly associated with increased depressive symptoms among older adults in the United States. The risk of depression was 2.64 times higher (95% confidence interval [CI]: 1.33-5.23) in those with cognitive impairment compared to those with normal cognitive function. Participants in the highest TyG quartile had a multivariable-adjusted odds ratio (OR) of 1.61 (95% CI: 1.10-2.35) for depression compared to those in the lowest quartile. Similar results were observed across different genders, age groups, and baseline comorbidities.

Our findings suggest that higher TyG index and cognitive impairment (including deficits in learning and memory, executive function, and attention/processing speed) are associated with a greater likelihood of depressive symptoms in older adults.