Table 2.
Restricted cubic spline regression model results with baseline measures predicting mean reaction time (RT) and intra-individual variation in reaction time (IIV) at follow-up (N = 13 342)
| Predictors | Outcomes β (95% CI) P value | |
|---|---|---|
| RT | IIV | |
| Mean reaction time baseline | 0.548 (0.529 to 0.561) <0.001 | – |
| Intra-individual variation at baseline | – | 0.178 (0.161 to 0.196) <0.001 |
| Alcohol use: spline 1 (linear effect ≤ 10 g/day) | −0.048 (−0.105 to −0.030) 0.001 | −0.055 (−0.125 to −0.034) 0.001 |
| Alcohol use: spline 2 (slope effect) | 0.035 (0.007 to 0.059) 0.013 | 0.034 (0.002 to 0.064) 0.039 |
| Age in years (at repeat assessment) | 0.135 (0.072 to 0.107) <0.001 | 0.085 (0.072 to 0.107) <0.001 |
| Gender (reference: female) | −0.023 (−0.037 to −0.008) 0.002 | −0.005 (−0.023 to 0.013) 0.558 |
| Education (reference: no degree) | −0.027 (−0.047 to −0.014) <0.001 | −0.031 (−0.047 to −0.014) <0.001 |
| Previous tobacco use (reference: non-smoker) | 0.020 (0.005 to 0.033) 0.008 | 0.008 (−0.009 to 0.025) 0.336 |
| Fit | R2 = 0.35; AIC = −13 691 | R2 = 0.05; AIC = 24 985 |
B, unstandardized regression coefficient; SE B, standard error for the unstandardized regression coefficient; β (95% CI), standardized regression coefficient and 95% confidence intervals. Note: results for smoking, walking, BMI and deprivation omitted as did not approach statistical significance for either outcome