Table 1.
Characteristics of study samples
| Whole sample (n = 2836) | MRI sample (n = 263) | |
|---|---|---|
| Gender | 49.5% girls 50.5% boys | 48.3% girls 51.7% boys |
| Age, years, mean ± SD (range) | 9.4 ± 0.9 (7.9–12.1) | 9.7 ± 0.9 (8.0–12.1) |
| Overall school achievement, 5‐point scale | 3.5 ± 1.1 (1–5) | 3.7 ± 1.0 (1–5) |
| Difficulties score (SDQ), range 0–40 | 8.4 ± 5.2 (0–32) | 8.8 ± 5.3 (0–25) |
| Obesity: Normal | 72.1% | 71.4% |
| Overweight, BMI ≥ 25–29.9 kg/m2 | 18.5% | 18.4% |
| Obesity, BMI ≥ 30 kg/m2 | 9.4% | 10.2% |
| Mother education (5‐point scale, 5 = University) | 4.4 ± 0.8 (1–5) | 4.5 ± 0.8 (1–5) |
| Father education (5‐point scale, 5 = University) | 4.4 ± 0.8 (1–5) | 4.4 ± 0.8 (1–5) |
| Vulnerability indexa–Home | 0.45 ± 0.21 (0.06–1.0) | 0.43 ± 0.21 (0.06–0.90) |
| Vulnerability indexa–School | 0.42 ± 0.21 (0.13–0.84) | 0.43 ± 0.22 (0.13–0.84) |
| Public/Nonpublic school | 36% vs. 64% | 43% vs. 57% |
| Task performance | ||
| Reaction time (mean of medians, msec) | 671.5 ± 124.6 (389–1277) | 650.6 ± 119.9 (431–1091) |
| Reaction time standard deviation (msec) | 235.7 ± 91.1 (60.6–598.6) | 222.9 ± 91.2 (77.5–571.6) |
| Commission errors (number) | 4.0 (3.1%) ± 4.2 (0–50) | 4.3 (3.4%) ± 5–0 (0–49) |
| Omission errors (number) | 1.4 (1.1%) ± 3.6 (0–94) | 1.6 (1.3%) ± 3.9 (0–44) |
BMI, body mass index; SDQ, Strengths and Difficulties Questionnaire.
a
Neighborhood socioeconomic status vulnerability index based on the level of education, unemployment, and occupation at the census tract (Atlas de vulnerabilidad urbana de España, 2012).