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Table 2 Linear growth model of Weight-for-Length/BMI z-score from birth to 72 months based on antibiotic exposure during the first year of life (n = 586)

From: The association between antibiotics in the first year of life and child growth trajectory

  Model 1 Model 2 Model 3
Estimate (S.E) P-value Estimate (S.E) P-value Estimate (S.E) P-value
Initial WL/BMI z-score (intercept) − 0.21 (0.05) < 0.0001 − 0.18 (0.05) 0.0006 −0.10 (0.35) 0.77
Linear time (months) 0.06 (0.007) < 0.0001 0.04 (0.009) < 0.0001 0.04 (0.009) < 0.0001
Quadratic time (months2) −0.0007 (0.0001) < 0.0001 − 0.0005 (0.0001) < 0.0001 − 0.0004 (0.0001) < 0.0001
Antibiotic course   0.009   0.09   0.10
 0 0   0   0  
 1–2 0.17 (0.08)   0.10 (0.09)   0.08 (0.09)  
 3+ 0.42 (0.16)   0.37 (0.18)   0.38 (0.18)  
Linear Time x Antibiotic course     0.003   0.002
 0    0   0  
 1–2    0.05 (0.02)   0.05 (0.02)  
 3+    0.04 (0.03)   0.04 (0.03)  
Quadratic Time x Antibiotic course     0.003   0.002
 0    0   0  
 1–2    −0.0007 (0.0002)   −0.0008 (0.0002)  
 3+    −0.0005 (0.0004)   −0.0005 (0.0004)  
  1. The models presented here included a random statement for the individual allowing variation in intercept, time, time2, and antibiotic course with a variance components (VC) covariance structure between the effects using a Maximum Likelihood Estimation method. Model 1 includes the effect of time, time2, and antibiotic dose on weight-for-length/BMI z-score changes from birth to 72 months. In Model 2, we included the variables for time x antibiotic course and time2x antibiotic course. Model 3 controlled for known covariates including maternal age, maternal BMI, race, marital status, income, education, smoking, diabetes, exclusive breastfeeding for 4 months, and infant sex. Entries show parameter estimates and standard errors in parentheses.