Table 2

Characteristics of the study population, by missing data and socioeconomic group

Missing data sample*Final sample†
OverallSocioeconomic position
LowMiddleHigh
Total unweighted (n)59266203159119872625
%%%%%
Socioeconomic position
 Low41.927.5 – –
 Middle34.532.6 – –
 High23.639.9 – –
Sex
 Female45.250.950.651.751.0
Ethnic group 
 White78.286.477.188.2
  Mixed2.72.74.51.62.3
 Indian2.11.91.22.32.1
 Pakistani and Bangladeshi8.45.010.15.01.5
 Black or Black British6.02.75.01.81.7
 Other2.71.32.01.20.9
Firstborn
 Yes43.750.745.652.852.2
Caesarean birth
 Yes16.519.614.220.022.7
Tobacco exposure in utero 
 Yes21.516.130.017.05.8
Tobacco exposure in infancy
  Yes21.414.930.215.34.1
Breast fed (months)
 <169.753.074.758.2033.6
 1–39.414.410.114.017.6
 >321.032.715.227.848.8
Non-allergic asthma
 Yes14.58.411.08.76.7
 Mean (SD)Mean (SD)Mean (SD)Mean (SD)Mean (SD)
Adiposity measures
 BMI z-score0.46 (1.15)0.33 (1.10)0.36 (1.22)0.40 (1.09)0.27 (1.02)
 Waist57.5 (6.4)57.0 (5.8)57.4 (6.6)57.2 (6.0)56.7 (5.1)
 WHtR0.46 (0.04)0.46 (0.04)0.47 (0.04)0.46 (0.04)0.46 (0.04)
  • *Unweighted proportions and mean (SD) presented.

  • †Weighted proportions and mean (SD) presented.

  • BMI, body mass index; WHtR, waist-to-height ratio.