Table 1. Baseline characteristics of children.
| Variable | All (n = 4,296) | Boys (n = 2,044) | Girls (n = 2,252) | |||
| Mean or Percent | SD | Mean or Percent | SD | Mean or Percent | SD | |
| Age (mo) | 140.8 | 2.8 | 140.8 | 2.8 | 140.8 | 2.7 |
| Height (cm) | 150.7 | 7.2 | 150.0 | 7.1 | 151.3 | 7.2 |
| Weight (kg) | 43.3 | 9.7 | 42.4 | 9.5 | 44.2 | 9.8 |
| BMI (kg/m2) | 18.9 | 3.3 | 18.7 | 3.2 | 19.1 | 3.4 |
| Fat mass (kg) measured by DXA | 11.5 | 6.5 | 10.2 | 6.4 | 12.7 | 6.4 |
| FMI (kg/m2) | 5.0 | 2.7 | 4.5 | 2.6 | 5.5 | 2.6 |
| Body fat percentage (fat mass [kg]/weight [kg]) | 25.4 | 9.1 | 22.5 | 9.2 | 27.3 | 8.4 |
| Total physical activity (counts/min) | 607.2 | 178.4 | 664.6 | 187.9 | 555.1 | 151.7 |
| Moderate-to-vigorous-intensity physical activity (min/d) a | 20.0 | 12.0–31.4 | 25.8 | 15.9–38.5 | 16.0 | 9.9–24.9 |
| Sedentary time (min/d) | 427.3 | 66.6 | 418.2 | 68.5 | 435.6 | 63.7 |
| Birth weight (g) | 3,433.8 | 526.7 | 3,483.5 | 568.3 | 3,388.3 | 481.2 |
| Gestational age at birth (wk) | 39.5 | 1.8 | 39.4 | 1.9 | 39.6 | 1.6 |
| Maternal BMI (kg/m2) | 22.9 | 3.7 | 23.0 | 3.7 | 22.9 | 3.7 |
| Total daily dietary intake (kcal/d) | 1,862.0 | 377.3 | 1,953.5 | 389.8 | 1,778.3 | 344.9 |
| Maternal smoking during pregnancy | ||||||
| No | 80.1% | 80.1% | 80.1% | |||
| Yes | 19.9% | 19.9% | 19.9% | |||
| Maternal education | ||||||
| Education up to age 16 y with certificate of secondary education or vocational training | 20.0% | 21.0% | 19.1% | |||
| Education up to age 16 y with general certificate of education (Ordinary level) | 35.1% | 34.4% | 35.8% | |||
| Education up to age 18 y with general certificate of education (Advanced level) | 27.2% | 26.8% | 27.5% | |||
| University degree | 17.7% | 17.8% | 17.6% | |||
| Parental social class b | ||||||
| I Professional occupations | 16.3% | 16.5% | 16.2% | |||
| II Managerial and technical occupations | 45.9% | 45.5% | 46.3% | |||
| III(NM) Skilled non-manual occupations | 24.4% | 24.8% | 24.0% | |||
| III(M) Skilled manual occupations | 9.6% | 9.9% | 9.4% | |||
| IV Partly skilled occupations | 3.3% | 2.9% | 3.6% | |||
| V Unskilled occupations | 0.5% | 0.5% | 0.5% | |||
| Stage of puberty c | ||||||
| Stage 1 | 47.7% | 66.7% | 33.2% | |||
| Stage 2 | 35.0% | 28.8% | 39.8% | |||
| Stage 3 | 13.7% | 4.2% | 21.0% | |||
| Stage 4 | 3.1% | 0.4% | 5.2% | |||
| Stage 5 | 0.5% | 0% | 0.8% | |||
Total sample sizes range from 3,121 to 4,098 depending on the availability of the data.
a
Median and interquartile ranges are displayed for this variable because it is skewed.
b
Based on parent with highest social class, as defined by the 1991 British Office of Population Censuses and Surveys classification.
c
Based on highest Tanner scale developmental stage of breasts and pubic hair for females and pubic hair for males.
DXA, dual energy X-ray absorptiometry.