Table 2.
Mean Differences in Baseline Cognitive Function and Annualized Rates of Cognitive Decline, by Depressive Symptom Categories
| Depression Category | Global¶ | Verbal¶ | Executive Function & Attention¶ | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model 1* (Age and education adjusted) | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ |
| Cross-Sectional | ||||||||||||
| Persistent Depression | −0.14 | (−0.22, −0.06) | <0.001 | −0.17 | (−0.26, −0.08) | <0.001 | −0.05 | (−0.15, 0.05) | 0.32 | |||
| Variable Depression | −0.04 | (−0.09,−0.004) | 0.03 | −0.03 | (−0.08, 0.01) | 0.16 | −0.06 | (−0.11, −0.01) | 0.03 | |||
| No Depression | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | |||
| Cognitive Change | ||||||||||||
| Persistent Depression | −0.02 | (−0.04, 0.001) | 0.06 | −0.01 | (−0.03, 0.02) | 0.64 | −0.03 | (−0.05, −0.01) | 0.002 | |||
| Variable Depression | −0.01 | (−0.02, 0.000) | 0.06 | −0.01 | (−0.02, −0.002) | 0.02 | 0.0004 | (−0.01, 0.01) | 0.93 | |||
| No Depression | Ref | Ref | Ref | 3.45; 0.03 | Ref | Ref | Ref | 2.74; 0.06 | Ref | Ref | Ref | 4.73; 0.01 |
| Model 2† (Main model) | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cross-Sectional | ||||||||||||
| Persistent Depression | −0.13 | (−0.21, −0.05) | 0.001 | −0.16 | (−0.26, −0.07) | <0.001 | −0.03 | (−0.13, 0.07) | 0.52 | |||
| Variable Depression | −0.04 | (−0.08, 0.004) | 0.08 | −0.02 | (−0.07, 0.02) | 0.29 | −0.04 | (−0.09, 0.01) | 0.10 | |||
| No Depression | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | |||
| Cognitive Change | ||||||||||||
| Persistent Depression | −0.02 | (−0.04, 0.002) | 0.09 | −0.004 | (−0.03, 0.02) | 0.71 | −0.03 | (−0.05, −0.01) | 0.003 | |||
| Variable Depression | −0.01 | (−0.02, 0.002) | 0.11 | −0.01 | (−0.02, −0.001) | 0.03 | 0.0003 | (−0.01, 0.01) | 0.95 | |||
| No Depression | Ref | Ref | Ref | 2.64; 0.07 | Ref | Ref | Ref | 2.28; 0.10 | Ref | Ref | Ref | 4.57; 0.01 |
| Model 3‡ (Including potential intermediates) | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ | Estimate | 95% CI | p-value | F; p-value§ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cross-Sectional | ||||||||||||
| Persistent Depression | −0.10 | (−0.18, −0.02) | 0.01 | −0.13 | (−0.22, −0.04) | 0.005 | −0.01 | (−0.11, 0.09) | 0.89 | |||
| Variable Depression | −0.02 | (−0.06, 0.02) | 0.34 | −0.01 | (−0.05, 0.04) | 0.73 | −0.03 | (−0.08, 0.02) | 0.26 | |||
| No Depression | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | Ref | |||
| Cognitive Change | ||||||||||||
| Persistent Depression | −0.01 | (−0.03, 0.01) | 0.16 | −0.001 | (−0.02, 0.02) | 0.92 | −0.03 | (−0.05, −0.01) | 0.006 | |||
| Variable Depression | −0.01 | (−0.01, 0.004) | 0.26 | −0.01 | (−0.02, 0.001) | 0.09 | 0.002 | (−0.01, 0.01) | 0.70 | |||
| No Depression | Ref | Ref | Ref | 1.54; 0.22 | Ref | Ref | Ref | 1.48; 0.23 | Ref | Ref | Ref | 3.93; 0.02 |
Model 1 (basic model): Age and Education adjusted. Mean interval between first and fourth wave of cognitive tests=5.5 years
Model 2 (basic model + lifestyle factors): Model 1 plus smoking status, alcohol consumption, BMI, physical activity
Model 3 (basic model + lifestyle factors + medical comorbidities + antidepressant use): Model 2 plus vascular risk factors (CVD [myocardial infarction, coronary artery bypass grafting, and/ or stroke], hypertension, dyslipidemia), other major comorbidities (diabetes, respiratory illness [asthma and/or Chronic Obstructive Pulmonary Disease], cancer history other than non-melanoma skin cancer), and antidepressant use
F-statistic is from global test of depression categories by time interaction; All models have 2 df for numerator
Denominator df: (Model 1 global=9231, verbal=9419, exec=9579), (Model 2 global=9224, verbal=9411, exec=9579), (Model 3 global=9217, verbal=9405, exec=9577)
Global score combines results of the Telephone Interview of Cognitive Status (TICS), category fluency, digit span backwards, immediate and delayed recall trials of East Boston Memory Test (EBMT), and delayed recall trial of the TICS 10-word list; Verbal score combines results of the immediate and delayed trials of EBMT and the TICS 10-word list; Executive Function and Attention score combines results of category fluency and digit span backwards.