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. Author manuscript; available in PMC: 2021 Nov 1.
Published in final edited form as: Environ Int. 2020 Aug 29;144:106062. doi: 10.1016/j.envint.2020.106062

Table 1:

Maternal and child characteristics by in utero and postnatal lead levels (N=146)

Variable Level 2nd Trimester Leada 3rd Trimester Leada Postnatal Leada
N Median
(IQR) or p
p-valueb N Median
(IQR) or p
p-valueb N Median
(IQR) or p
p-valueb
Maternal education dHS diploma 13 0.024 (0.018) 0.26 13 0.026 (0.013) 0.087 13 0.023 (0.026) 0.077
Some college 61 0.027 (0.037) 64 0.033 (0.047) 65 0.030 (0.029)
≥Bachelor’s Degree 62 0.022 (0.026) 65 0.031 (0.034) 65 0.024 (0.030)
Household income <$20,000 9 0.024 (0.011) 0.98 9 0.033 (0.030) 0.89 9 0.027 (0.021) 0.49
$20,000-<$40,000 24 0.026 (0.032) 25 0.032 (0.033) 26 0.028 (0.031)
$40,000-<$80,000 40 0.029 (0.024) 44 0.035 (0.040) 45 0.032 (0.036)
$80,000-<$ 100,000 25 0.021 (0.030) 25 0.027 (0.041) 24 0.022 (0.024)
≥$100,000 23 0.021 (0.028) 24 0.032 (0.034) 24 0.025 (0.028)
Refused to Answer 15 0.020 (0.053) 15 0.028 (0.045) 15 0.022 (0.046)
Married No 36 0.028 (0.051) 0.089 38 0.034 (0.066) 0.14 39 0.034 (0.040) 0.063
Yes 100 0.023 (0.026) 104 0.030 (0.033) 104 0.024 (0.026)
Location of residence Suburban 85 0.021 (0.026) 0.024 88 0.027 (0.030) 0.005 89 0.022 (0.028) 0.003
Urban 51 0.028 (0.039) 54 0.041 (0.056) 54 0.033 (0.027)
Maternal age at birth --- 136 0.056 0.52 142 0.094 0.27 143 0.054 0.52
Maternal BMI at first prenatal visit --- 135 −0.014 0.87 141 0.031 0.72 142 0.064 0.45
Mother Atopic No 62 0.025 (0.037) 0.79 64 0.032 (0.047) 0.69 66 0.024 (0.035) 0.55
Yes 71 0.024 (0.026) 75 0.030 (0.033) 74 0.029 (0.023)
Prenatal antibiotic use No 54 0.023 (0.027) 0.37 57 0.033 (0.040) 0.74 57 0.024 (0.027) 0.16
Yes 77 0.025 (0.032) 78 0.031 (0.044) 79 0.029 (0.032)
Prenatal antifungal use No 108 0.026 (0.029) 0.20 112 0.033 (0.045) 0.18 113 0.029 (0.031) 0.097
Yes 23 0.024 (0.030) 23 0.026 (0.025) 23 0.021 (0.022)
Mother smoked during pregnancy No 127 0.024 (0.028) 0.33 133 0.031 (0.038) 0.41 134 0.027 (0.028) 0.84
Yes 9 0.035 (0.045) 9 0.042 (0.075) 9 0.024 (0.033)
ETS during pregnancy No 107 0.024 (0.026) 0.13 112 0.030 (0.037) 0.18 112 0.027 (0.028) 0.34
Yes 29 0.035 (0.044) 30 0.039 (0.059) 31 0.027 (0.033)
Prenatal indoor pets No 76 0.029 (0.042) 0.058 80 0.038 (0.048) 0.019 82 0.028 (0.030) 0.19
Yes 60 0.021 (0.020) 62 0.026 (0.024) 61 0.024 (0.027)
Year House was Built 1980 or after 26 0.023 (0.030) 0.40 28 0.026 (0.036) 0.16 28 0.022 (0.024) 0.099
Before 1980 104 0.024 (0.028) 108 0.032 (0.038) 109 0.027 (0.031)
First born child No 79 0.025 (0.019) 0.90 83 0.032 (0.032) 0.64 85 0.027 (0.027) 0.81
Yes 57 0.024 (0.033) 59 0.030 (0.051) 58 0.027 (0.031)
Season of birth Winter 29 0.022 (0.022) 0.52 30 0.029 (0.035) 0.65 31 0.029 (0.033) 0.88
Spring 34 0.029 (0.048) 36 0.034 (0.058) 37 0.025 (0.039)
Summer 35 0.021 (0.028) 37 0.030 (0.032) 37 0.024 (0.026)
Fall 38 0.026 (0.032) 39 0.032 (0.045) 38 0.029 (0.021)
Mode of delivery Vaginal 83 0.023 (0.026) 0.31 87 0.029 (0.034) 0.29 88 0.026 (0.026) 0.49
C-Section 52 0.028 (0.033) 54 0.034 (0.045) 54 0.028 (0.030)
Gestational age at birth --- 133 0.013 0.88 142 −0.023 0.79 139 0.01 0.91
Birthweight z-score --- 124 −0.208 129 −0.207 0.019 131 −0.184 0.036
Child race White 50 0.018 (0.018) <0.001 52 0.022 (0.025) <0.001 52 0.020 (0.019) <0.001
Black 56 0.031 (0.050) 58 0.044 (0.061) 59 0.032 (0.033)
Other/Mixed 30 0.024 (0.022) 32 0.031 (0.041) 32 0.031 (0.032)
Child sex Male 66 0.029 (0.026) 0.072 69 0.036 (0.039) 0.065 70 0.029 (0.020) 0.33
Female 70 0.021 (0.026) 73 0.027 (0.035) 73 0.024 (0.036)
Breastfeeding status at 1-month Formula Feeding 25 0.032 (0.030) 0.32 26 0.042 (0.048) 0.58 26 0.028 (0.033) 0.60
Mixed Feeding 81 0.023 (0.028) 85 0.031 (0.049) 87 0.027 (0.029)
Exclusive Breastfeed 30 0.029 (0.025) 31 0.029 (0.023) 30 0.026 (0.031)
Breastfeeding status at 6-months Formula Feeding 25 0.032 (0.030) 0.38 26 0.042 (0.048) 0.58 26 0.028 (0.033) 0.93
Mixed Feeding 95 0.024 (0.027) 99 0.031 (0.042) 100 0.027 (0.026)
Exclusive Breastfeed 16 0.024 (0.023) 17 0.026 (0.029) 17 0.025 (0.033)
a

tooth lead levels shown as metal-to-calcium ratios.

b

Kruskal-Wallis or Spearman correlation p-value.