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. Author manuscript; available in PMC: 2020 Jan 19.
Published in final edited form as: Nicotine Tob Res. 2018 Jul 19:10.1093/ntr/nty148. doi: 10.1093/ntr/nty148

Table 2.

Linear mixed regression analysis: Association between prenatal tobacco exposure and (A) average length/height z-score over 60 months (B) relative length/height growth rate of offspring

(A) Average length/height z-score (B) Relative growth rate (SDs/year) b
birth to 60 monthsa birth to 60 months 0-12 months 12-36 months 36-60 months
Maternal plasma cotinine
(ng/mL) and ETS status
      <0.17, ETS (-) Reference  Reference    Reference    Reference   Reference
      <0.17, ETS (+) -0.08 (-0.21 ,0.05) 0.03 (<0.01 ,0.06)*   0.08 (-0.11 ,0.27)   0.03 (-0.03 ,0.09) 0.01 (-0.02 ,0.04)
      0.17-13.99 -0.01 (-0.17 ,0.16) 0.02 (-0.02 ,0.05) -0.05 (-0.29 ,0.19)   0.05 (-0.02 ,0.12) 0.02 (-0.02 ,0.05)
      14 and Above -0.35 (-0.64 ,-0.06)* 0.06 (-0.01 ,0.14)   0.43 (-0.02 ,0.87) -0.05 (-0.20 ,0.09) 0.03 (-0.04 ,0.11)
*

p value <0.05

a

Models adjusted for prenatal tobacco exposure grouping (Groups 1 to 4 based on maternal plasma cotinine and ETS status), ethnicity, maternal age at delivery, maternal education level, parity, 1st trimester maternal BMI, maternal height, gestational age at birth and age of visit, with random intercept and random slope model.

b

Models adjusted for prenatal tobacco exposure grouping (Groups 1 to 4 based on maternal plasma cotinine and ETS status), ethnicity, maternal age at delivery, maternal education level, parity, 1st trimester maternal BMI, maternal height and gestational age at birth, age of visit and interaction of ETS*age of visit with random intercept and random slope model.

ETS: Environmental tobacco smoke exposure