Table 4.
Obvious depression scale: effects on WAIS IQs from 50 to 80.
| Model | Coefficient1 | 95% CI | P for main effect | Interaction2 coefficient | P for interaction |
|---|---|---|---|---|---|
| Full-scale IQ | |||||
| Model 1: unadjusted3 | −0.639 | (−0.83)–(−0.44) | <0.001 | 0.003 | 0.319 |
| Model 2: demographics4 | −0.184 | (−0.35)–(−0.02) |
0.029 | 0.003 | 0.291 |
| Model 3: lifestyle factors5 | − 0.190 | (−0.36)–(−0.03) | 0.023 | 0.003 | 0.294 |
| Verbal IQ | |||||
| Model 1: unadjusted3 | − 0.572 | (−0.77)–(−0.38) | <0.001 | 0.002 | 0.638 |
| Model 2: demographics4 | − 0.119 | (−0.28)–(0.05) |
0.156 | 0.002 | 0.613 |
| Model 3: lifestyle factors5 | − 0.125 | (−0.29)–(0.04) | 0.131 | 0.002 | 0.616 |
| Performance IQ | |||||
| Model 1: unadjusted3 | − 0.595 | (−0.78)–(−0.41) | <0.001 | 0.005 | 0.227 |
| Model 2: demographics4 | − 0.223 | (−0.40)–(−0.05) |
0.012 | 0.005 | 0.236 |
| Model 3: lifestyle factors5 | − 0.228 | (−0.40)–(−0.06) | 0.009 | 0.005 | 0.236 |
1Fixed effect coefficient from a model only including the main effect of the depression scale. See Section 3 for description of the effects of obvious depression on the estimates of the random effects.
2Interaction coefficient from a model including a term for interaction between the obvious depression scale and time since baseline. Additionally all relevant main effects are included in the model.
3Model includes linear and quadratic time since baseline and the obvious depression scale.
4Model additionally includes sex, education, and social status.
5Model additionally includes sex, education, social status, systolic blood pressure, smoking, BMI, total cholesterol, triglycerides, insulin, and leisure and work physical activity.