Table 3

Associations of maternal smoking during pregnancy and maternal early pregnancy overweight (BMI ≥25.0) with offspring BMI z-score trajectories

Sex-adjusted model*
Maternal smoking during pregnancyMaternal early pregnancy BMI (kg/m2)
BMI z-score trajectoriesNo (n=750)Yes (n=213)<25.0 (n=636)≥25.0 (n=327)
Normal (Reference), n (%)550 (73.3)132 (62.0)483 (75.9)199 (60.9)
Early persistent obesity, n (%)27 (3.6)12 (5.6)17 (2.8)22 (6.7)
RR (95% CI)1.001.83 (1.02 to 3.49)1.002.84 (1.54 to 5.25)
p Value0.044<0.001
Delayed overweight, n (%)80 (10.7)34 (16.0)53 (8.3)61 (18.7)
RR (95% CI)1.001.61 (1.13 to 2.28)1.002.32 (1.66 to 3.25)
p Value0.008<0.001
Early transient overweight, n (%)93 (12.4)35 (16.4)83 (13.1)45 (13.8)
RR (95% CI)1.001.41 (0.93 to 2.01)1.001.28 (0.92 to 1.77)
p Value0.0760.144
Adjusted model†
Maternal smoking during pregnancyMaternal early pregnancy BMI (kg/m2)
BMI z-score trajectoriesNo (n=657)Yes (n=164)<25.0 (n=543)≥25.0 (n=278)
Normal (Reference), n (%)474 (72.2)100 (61.0)409 (75.3)165 (59.4)
Early persistent obesity, n (%)19 (2.9)9 (5.5)12 (2.2)16 (5.8)
RR (95% CI)1.002.16 (1.02 to 4.68)1.003.16 (1.52 to 6.58)
p Value0.0410.002
Delayed overweight, n (%)79 (12.0)28 (17.1)49 (9.0)58 (20.8)
RR (95% CI)1.001.69 (1.15 to 2.49)1.002.45 (1.73 to 3.46)
p Value0.008<0.001
Early transient overweight, n (%)85 (12.9)27 (16.4)73 (13.5)39 (14.0)
RR (95% CI)1.001.35 (0.90 to 2.00)1.001.25 (0.88 to 1.77)
p Value0.1440.215
  • *Model included the flowing variables: maternal smoking during pregnancy, maternal early pregnancy BMI, and sex.

  • †Model included the following variables: maternal smoking during pregnancy, maternal early pregnancy BMI, sex, birth weight, gestational age at birth, maternal age at delivery, duration of breastfeeding, maternal education and socioeconomic status.

  • BMI, Body Mass Index; n, number; RR, Risk ratio.