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Table 4 The effects of iodine intake and other covariates on natural logarithm of placental weight in univariate and multivariate models

From: Estimated dietary iodine intake as a predictor of placental size: evidence from the ELSPAC study

  Univariate models Multivariate model
β estimate 95% CI for β estimate p-value β estimate 95% CI for β estimate p-value
Iodine intake [100 μg/day] −0.032 (−0.050; −0.013) <0.001 −0.025 (−0.044; −0.006) 0.011
Gestational diabetes
 No (ref)    (ref)   
 Yes −0.088 (−0.149; −0.027) 0.005 −0.080 (−0.140; −0.020) 0.009
Pre-eclampsia
 No (ref)    (ref)   
 Yes −0.105 (−0.208; −0.002) 0.046 −0.133 (−0.234; −0.031) 0.011
Gestational hypertension
 No (ref)    (ref)   
 Yes 0.062 (0.010; 0.113) 0.019 0.053 (0.001; 0.104) 0.046
Gestational age [w] 0.015 (0.010; 0.019) <0.001 0.013 (0.009; 0.018) <0.001
Stillborn
 No (ref)    (ref)   
 Yes −0.064 (−0.149; 0.022) 0.143 −0.056 (−0.140; 0.028) 0.193
IVF pregnancy
 No (ref)    (ref)   
 Yes 0.131 (0.041; 0.220) 0.004 0.141 (0.051; 0.230) 0.002
Congenital malformations
 No (ref)    (ref)   
 Yes 0.016 (−0.025; 0.057) 0.453 0.016 (−0.025; 0.056) 0.443
Smoking
 Never (ref)    (ref)   
 Past smoker 0.012 (−0.005; 0.029) 0.152 0.008 (−0.009; 0.025) 0.353
 Current smoker −0.024 (−0.052; 0.005) 0.100 −0.019 (−0.049; 0.011) 0.206
Substance abuse
 No (ref)    (ref)   
 Yes −0.050 (−0.134; 0.034) 0.239 −0.033 (−0.116; 0.051) 0.443
Alcohol
 No (ref)    (ref)   
 Yes −0.018 (−0.048; 0.013) 0.261 −0.020 (−0.050; 0.011) 0.213
Nutritional supplements
 No (ref)    (ref)   
 Yes 0.050 (0.035; 0.066) <0.001 0.047 (0.031; 0.063) <0.001
ISCO skill level - mother
 Skill level 1 (ref)    (ref)   
 Skill level 2 0.005 (−0.031; 0.040) 0.805 0.001 (−0.036; 0.037) 0.978
 Skill level 3 −0.009 (−0.048; 0.030) 0.639 −0.015 (−0.056; 0.027) 0.493
 Skill level 4 −0.006 (−0.043; 0.031) 0.741 −0.014 (−0.055; 0.027) 0.506
 Skill level unassigned −0.051 (−0.176; 0.075) 0.428 −0.056 (−0.179; 0.068) 0.377
ISCO skill level - father
 Skill level 1 (ref)    (ref)   
 Skill level 2 −0.006 (−0.059; 0.046) 0.814 −0.007 (−0.059; 0.044) 0.783
 Skill level 3 −0.026 (−0.083; 0.031) 0.369 −0.019 (−0.076; 0.038) 0.508
 Skill level 4 −0.013 (−0.066; 0.041) 0.641 0.010 (−0.046; 0.065) 0.734
 Skill level unassigned 0.004 (−0.056; 0.064) 0.894 0.026 (−0.033; 0.085) 0.386
Education – mother
 Basic (ref)    (ref)   
 Secondary 0.005 (−0.012; 0.023) 0.529 0.022 (0.002; 0.043) 0.035
 University and higher 0.000 (−0.021; 0.022) 0.977 0.033 (0.001; 0.065) 0.043
Education – father
 Basic (ref)    (ref)   
 Secondary −0.001 (−0.021; 0.018) 0.880 −0.001 (−0.023; 0.021) 0.936
 University and higher −0.016 (−0.035; 0.003) 0.090 −0.025 (−0.054; 0.004) 0.091
Equalized family intake [1000 CZK/month] −0.002 (−0.011; 0.008) 0.698 −0.002 (−0.012; 0.009) 0.732
Age - mother [y] 0.001 (−0.001; 0.002) 0.377 0.000 (−0.001; 0.002) 0.669
Height - mother [cm] 0.002 (0.000; 0.003) 0.012 0.002 (0.000; 0.003) 0.014
Height - father [cm] 0.000 (−0.001; 0.001) 0.973 0.000 (−0.002; 0.001) 0.501
Maternal preconceptional BMI [kg/m2] 0.008 (0.006; 0.010) <0.001 0.007 (0.005; 0.010) <0.001
Ethnicity – mother
 European (ref)    (ref)   
 Others −0.029 (−0.100; 0.042) 0.429 0.020 (−0.063; 0.104) 0.632
Ethnicity – father
 European (ref)    (ref)   
 Others −0.039 (−0.094; 0.016) 0.168 −0.018 (−0.083; 0.047) 0.591
Sex of the child
 Girl (ref)    (ref)   
 Boy 0.029 (0.014; 0.045) <0.001 0.029 (0.014; 0.045) <0.001