Table 3.
Determinants of the neurological parameters
| |
Continuous performance (N = 489) |
Digit symbol (N = 340) |
Digit span |
Finger tapping |
||||
|---|---|---|---|---|---|---|---|---|
| Reaction time (msec)A | Errors of omissionB | Errors of commissionB | Total latency (sec)A | ForwardA(N = 511) | BackwardA(N = 499) | Preferred handA(N = 511) | Non-preferred handA(N = 509) | |
|
Boys |
|
0.43 (0.12)** |
0.29 (0.06)** |
4.12 (1.82)* |
|
|
9.71 (3.59)** |
5.53 (3.09) |
|
Age, 1 year increase |
−8.57 (2.79)** |
−0.14 (0.08) |
−0.15 (0.04)** |
−5.21 (1.21)** |
|
|
|
5.47 (2.2)* |
|
BMI, IQR increase = 3.4 kg/m2 |
|
|
0.06 (0.03) |
2.22 (0.97)* |
|
|
|
|
|
Education type – general |
−15.09 (3.76)** |
−0.54 (0.11)** |
−0.17 (0.06)** |
−9.73 (1.82)** |
0.44 (0.09)** |
0.53 (0.09)** |
|
8.12 (3.05)** |
|
Parents: no diplomaC |
|
|
|
|
|
|
|
|
|
9 gradesC |
|
|
|
|
|
|
−14.26 (5.7)* |
|
|
12 gradesC |
|
|
|
|
−0.17 (0.1) |
|
|
|
|
Alcohol use |
|
|
0.11 (0.07) |
|
|
0.19 (0.1) |
|
|
|
Computer useD |
−5.26 (2.37)* |
|
|
|
|
|
|
|
|
Physical activity |
−10.24 (4.57)* |
|
|
|
|
|
14.72 (4.23)** |
7.47 (3.61)* |
|
Blood lead, 2-fold increase |
|
|
|
3.58 (1.6)* |
−0.14 (0.07) |
|
|
|
| Sum PCB’s, 2-fold increase | −0.14 (0.07)* | −0.06 (0.03) | 0.14 (0.05)** | 0.09 (0.05) | 4.44 (2.07)* | 4.74 (1.79)** | ||
*p < 0.05, **p < 0.01.
A Estimated effect (standard deviation) from a linear model.
B Estimated effect (standard deviation) from a negative binomial model.
C Reference category: college or university diploma.
DThe effect of a one level increase of category.
Stepwise regression estimates of the effects of covariates on the neurological parameters with p = 0.15 for entering and p = 0.10 for remaining in the model. All covariates included in one of the models are shown in the table. The set of considered covariates included: gender, age, BMI, type of education (general secondary education versus other), the highest level of education of parents (three indicator variables), whether or not the parents owned the house, smoking, passive smoking, alcohol use at least once a month, computer use, fish consumption, physical activity in leisure time at least once a week, the logarithm of blood lead and the logarithm of serum PCB’s 138, 153, and 180.