APPENDIX 2

Distribution of Biological, Socioeconomic, and Psychosocial Factors for the Analysis Sample and Excluded Sample of Infants in the MCS

Analysis Sample,a %Excluded Sample,a %Pb
Mother's age at birth, y.02
    14–197.077.88
    20–2943.4643.51
    30–3947.3945.65
    40+2.092.96
Birth weight, g<.00005
    <25000.0037.79
    2500–299914.1621.19
    3000–349939.3521.27
    3500–399932.6013.31
     >400013.896.43
Gestation, wk<.00005
    <370.0040.94
    37–3819.0521.29
    39–4053.4627.27
    >4027.4910.49
Smoking during pregnancy<.00005
    081.7078.23
    1–10/d13.9115.71
    >10/d4.396.06
Social class<.00005
    Higher professional/managerial16.0514.13
    Lower professional/managerial22.0818.45
    Intermediate occupations7.636.14
    Small employers and self employed1.069.96
    Lower supervisory and technical12.6112.78
    Semiroutine occupations13.7315.74
    Routine occupations13.4515.88
    Unclassifiable3.856.94
Mother's educational qualifications<.00005
    Level 010.3719.16
    Level 18.148.11
    Level 229.9718.18
    Level 314.5312.97
    Level 430.8425.75
    Level 54.022.62
    Other2.133.22
Mother's employment status<.00005
    Full-time work15.1913.51
    Part-time work32.2925.83
    Nonworking52.5260.66
Partnership status.001
    Partnered86.6884.36
    Lone parent13.3215.64
No. of siblings<.00005
    041.7840.49
    137.1333.59
    2 or more21.1025.92
Care while working<.00005
    Parents13.3510.65
    Relative17.1012.74
    Nursery8.285.21
    Other8.146.42
    Not applicable53.1464.98
Cared for by others, h/wk<.00005
    047.5455.40
    1–105.944.28
    11–2018.4814.70
    21–3013.7411.08
    31–4011.5412.01
    41–502.181.99
    >500.590.53
MeanMean
Malaise scale1.561.82<.00005
Postnatal attachment scale51.3050.94.002
Attitude toward stimulating infant1.401.41.26
Attitude toward cuddling infant1.171.19.02
Attitude toward talking to infant1.181.20.007
  • a Percentages and means are adjusted for the clustered survey design and weighted to the UK population.

  • b Pearson χ2 test or test of difference between means, both with correction for clustered survey design.