Table 1 Descriptive statistics
N = 515A | |
|---|---|
Boys | 271 (52.6%) |
Age, years | 14.9 (0.7) |
BMI, kg/m2 | 20.4 (3.1) |
Type of education – general secondary | 290 (56.3%) |
The highest level of education of parents | |
no diploma | 22 (4.3%) |
9 grades | 52 (10.1%) |
12 grades | 163 (31.7%) |
College of university diploma | 278 (54%) |
Parents owning the house | 456 (88.5%) |
Current smoking | 65 (12.6%) |
Passive smokingB | 82 (15.9%) |
Alcohol use at least once a month | 129 (25%) |
Number of hours a week using computer | |
< 2 | 50 (9.7%) |
2-9 | 271 (52.6%) |
10-19 | 147 (28.5%) |
≥ 20 | 47 (9.1%) |
Fish consumptionC | |
Low | 224 (43.5%) |
Average | 186 (36.1%) |
High | 105 (20.4%) |
Physical activity in leisure time at least once a week | 405 (78.6%) |
Blood lipids, mg/dl | 448.9 (72.9) |
Blood lead, μg/dl | 1.4 (0.7 to 2.9) |
Sum of serum PCB 138, 153 and 180, ng/L | 171.6 (58 to 445) |
Thyroid hormones serum levels | |
FT3, pg/mL | 4.15 (0.53) |
FT4, ng/dL | 1.24 (0.17) |
TSH, μU/mL | 2.15 (0.99 to 4.45) |
Neurobehavioral parameters | |
Continuous Performance, reaction time, msec, N = 489 | 409.2 (41.8) |
Continuous Performance, errors of omission, N = 489 | 2.3 (2.7) |
Continuous Performance, errors of commission, N = 489 | 5.6 (3.5) |
Digit Symbol, sec, N = 340 | 98.3 (17.7) |
Digit Span Forward, N = 511 | 5.6 (1.03) |
Digit Span Backward, N = 499 | 4.49 (1.01) |
Finger Tapping, preferred hand, N = 511 | 293.7 (40.2) |
Finger Tapping, non-preferred hand, N = 509 | 258.6 (33.8) |