Table 1

Comparison of Southampton Women's Survey mother-child pairs with complete data with those lacking either maternal body composition or 6-year follow-up data, but born in the same time period

Participating mother-child pairs (n=940)Mother-child pairs with missing data (n=589)p Value
Maternal characteristics
  Age at child's birth, years (mean (SD))30.3 (3.8)29.7 (3.8)0.007
 Primiparous (n (%))
  No494 (52.6)355 (60.3)0.003
  Yes446 (47.5)234 (39.7)
 Qualifications (n (%))
  None15 (1.6)36 (6.1)<0.001
  GCSE D–G88 (9.4)67 (11.4)
  GCSE A*–C278 (29.6)165 (28.1)
  A level270 (28.8)175 (29.8)
  HND66 (7.0)39 (6.6)
  Degree222 (23.6)106 (18.0)
 Parents’ social class (n (%))
  I100 (10.8)52 (12.3)0.019
  II454 (48.8)178 (42.3)
  IIIN263 (28.5)112 (26.6)
  IIIM72 (7.7)51 (12.1)
  IV39 (4.2)20 (4.8)
  V2 (0.2)8 (1.9)
 Smoked in pregnancy (n (%))
  No768 (84.9)431 (77.2)<0.001
  Yes137 (15.1)127 (22.8)
 Maternal asthma (n (%))
  No733 (78.7)442 (76.2)0.251
  Yes198 (21.3)138 (23.8)
 Maternal childhood eczema (n (%))
  No758 (81.5)476 (82.1)0.783
  Yes172 (18.5)104 (17.9)
 Maternal rhinitis (n (%))
  No539 (57.9)353 (60.9)0.254
  Yes392 (42.1)227 (39.1)
 Maternal atopy (n (%))
  No438 (53.0)236 (57.0)0.185
  Yes388 (47.0)178 (43.0)
 Height, cm (mean (SD))163.5 (6.6)162.7 (6.0)0.020
 BMI, kg/m2 (median, (IQR))24.3 (22.0–27.5)24.1 (21.8–27.4)0.657
 Fat mass, kg (median, (IQR))20.3 (16.3–25.9)19.5 (15.7–25.8)0.116
Child's characteristics
 Gender (n (%))
  Male485 (51.6)313 (53.4)0.489
  Female455 (48.4)273 (46.6)
 Birth weight, kg (mean (SD))3.440 (0.551)3.420 (0.580)0.615
 Gestational age, weeks (median (IQR))40.1 (39.0–41.0)40.0 (39.1–41.0)0.969
 Mother smoked during child's infancy (n (%))
  No768 (84.9)431 (77.2)<0.001
  Yes137 (15.1)125 (22.8)
  • Numbers do not always add to the full column totals due to missing data.

  • Binary outcomes were compared by χ2 test, categorical outcomes by a χ2 test for trend, and continuous variables using t tests, after transformation where appropriate, or a rank-sum test.