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Table 3 GLM results for associations between prenatal lead and infant ABR C-P ratioa and grating VA

From: Low-level prenatal lead exposure and infant sensory function

  Crude Semi-adjustedb Fully-adjustedc
N β (95 % CI)d N β (95 % CI)d N β (95 % CI)d
ABR C-P ratio
 Mid-pregnancy lead 304   292   292  
  High (>3.8 μg/dL)   0.02 (−0.00–0.05)   0.02 (−0.01–0.05)   0.02 (−0.01–0.05)
  Med. (2–3.8 μg/dL)   0.02 (−0.01–0.05)   0.02 (−0.01–0.05)   0.02 (−0.01–0.05)
  Low (<2 μg/dL); Reference   p-trend = 0.09   p-trend = 0.12   p-trend = 0.13
 Late-pregnancy lead 315   304   304  
  High (>3.8 μg/dL)   0.04 (0.02–0.07)**   0.05 (0.02–0.08)***   0.05 (0.02–0.07)**
  Med. (2–3.8 μg/dL)   0.03 (0.00–0.05)   0.03 (0.01–0.06)*   0.03 (0.00–0.06)**
  Low (<2 μg/dL); Reference   p-trend = 0.002**   p-trend < 0.001***   p-trend = 0.002**
 Cord lead 277   267   267  
  High (>3.2 μg/dL)   0.00 (−0.03–0.03)   0.00 (−0.02–0.03)   0.00 (−0.03–0.03)
  Med. (2–3.2 μg/dL)   −0.00 (−0.03–0.02)   −0.00 (−0.03–0.03)   −0.00 (−0.03–0.03)
  Low (<2 μg/dL); Reference   p-trend = 0.99   p-trend = 0.81   p-trend = 0.88
Grating VA
 Mid-pregnancy lead 1000   990   961  
  High (>3.8 μg/dL)   0.00 (−0.06–0.08)   −0.03 (−0.09–0.03)   −0.02 (−0.08–0.04)
  Med. (2–3.8 μg/dL)   0.02 (−0.05–0.09)   0.02 (−0.04–0.08)   0.03 (−0.03–0.09)
  Low (<2 μg/dL); Reference   p-trend = 0.90   p-trend = 0.36   p-trend = 0.52
 Late-pregnancy lead 1019   1016   985  
  High (>3.8 μg/dL)   −0.12 (−0.19--0.05)**   −0.08 (−0.14--0.02)*   −0.09 (−0.15--0.02)**
  Med. (2–3.8 μg/dL)   −0.08 (−0.16--0.01)*   −0.07 (−0.13--0.01)*   −0.07 (−0.13--0.01)*
  Low (<2 μg/dL); Reference   p-trend = 0.002**   p-trend = 0.01*   p-trend = 0.009**
 Cord lead 916   916   888  
  High (>3.2 μg/dL)   −0.02 (−0.10–0.05)   −0.03 (−0.09–0.03)   −0.03 (−0.10–0.03)
  Med. (2–3.2 μg/dL)   −0.05 (−0.12–0.02)   −0.05 (−0.11–0.01)   −0.05 (−0.11–0.01)
  Low (<2 μg/dL); Reference   p-trend = 0.45   p-trend = 0.25   p-trend = 0.22
  1. a32 ms masking condition
  2. bAdjusted for sex, age at testing, cord blood iron status
  3. cAdjusted for sex, age at testing, cord blood iron status, gestational age, birth weight, head circumference
  4. dEffect estimates are reported in cycles/degree for VA; ABR C-P ratio has no units (ms/ms)
  5. p < 0.10; * p < 0.05; ** p < 0.01; *** p < 0.001