Associations between prenatal exposure to a mixture of lead,

Overview

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Key numbers

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• age = 18.5 years, range = 16.0 to 21.9) from Nunavik, Canada, completed four tasks assessing
• remained statistically significant after controlling for postnatal exposure (β = −0.178, 95 % CI =
• to be a part of the NCBM between 1993 and 1998 (N = 491; Dewailly et al., 1993)
• and in the NIH prospective infancy study between 1995 and 2002 (N = 221; Muckle et
• age, children of these two cohorts were recruited to form the NCDS cohort (N = 294;
• 2013 and 2016 (N = 212) when they were approximately 18 years old to evaluate executive
• health or neurological problems unrelated to exposure (epilepsy n = 2; traumatic brain injury
• n = 1; meningitis n = 1; multiple sclerosis n = 1). Forty-nine additional individuals could
• be contacted (death n = 9; incarcerated or in probation n = 12; moved, hospitalized or could
• 0.98; median r = 0.90; Ayotte et al., 2003). PCB-153 concentrations were expressed on
• limits of detection (LODs) in cord samples were 0.02 μg/dL for Pb and Hg, 0.71 μg/dL for
• Se, and 0.02 μg/L for all PCB congeners. LODs in postnatal blood samples were 0.01 μg/dL
• for Hg, 0.002 μg/dL for Pb, 0.71 μg/dL for Se, and <0.05 μg/L for all PCB congeners except
• PCB 52 (0.15 μg/L). Details on the analytical procedures can be found elsewhere (Dallaire
• were excluded from the analyses: Accuracy on stop trials less than 20 % (n = 6), accuracy on
• go trials less than 80 % (n = 1), SSRT score under 50 ms (n = 1), or other task administration
• problems such as issues with understanding the task, random button pressing, etc. (n = 11).
• was at least 3 standard deviations (SD) over or under the mean (n = 2 for cord DHA
• concentrations, n = 1 for cord Se concentrations, n = 1 for child Hg concentrations, n =
• 1 for child PCB-153 concentrations, n = 2 for adolescent Pb concentrations, n = 1 for
• adolescent Hg concentrations, n = 1 for SSRT). These variables were winsorized at 3 SD,
• 2.4.2. Missing data: All independent variables had under 10 % of their observations
• which was missing for 13 % of the participants (n = 27). For dependent variables, missing
• observations exceed 10 % of the sample for the 2n-back task (n = 64; 32 % of observations)
• et al., 2015, 2018). To do so, we first mean-centered and standardized all continuous
• mean task score with 95 % confidence intervals (CIs) with every z-score increase of natural
• is a successful inhibition on approximately 50 % of the stop trials (Band et al., 2003;
• (SD = 1.10, range = 16.0 to 21.9) at testing and 56 % of participants were women. About
• principal financial support provider was situated in the low end of the scale (mean = 22.00,
• SD = 9.00, range = 11 to 47). Tobacco was the most reported substance consumed by the
• Results from the multiple linear regressions are presented in Table 2. No associations
• were associated with lower cognitive planning scores (β = −0.146, 95 % CI = (−0.285,
• our cohort. For ln(cord blood Pb concentrations), we first computed a 95 % confidence
• near the mean of the Pb exposure distribution, a 2.3174 μg/dL increase in cord blood
• Pb increase required for a 2.336-score drop varies relative to the mean: smaller increases
• adolescent Pb blood levels (β = −0.178, 95 % CI = (−0.337, −0.025), p = 0.021). When
• inhibited between 40 % and 60 % of the stop trials. Cord blood Pb was positively associated
• of statistical significance (β = 0.143, 95 % CI = (−0.025, 0.298), p = 0.078; Table S1). For
• (estimated at 2.3174 μg/dL, see supplementary materials), the mean stop signal reaction time
• for postnatal Pb exposure (β = −0.184, 95 % CI = (−0.340, −0.021), p = 0.024).
• planning model (β = −0.294, 95 % CI = (−0.556, −0.025), p = 0.027). However, PCB-153
• was not significant in either men (β = 0.156, 95 % CI = (−0.096, −0.345), p = 0.165) or

Methods (brief)

• London. Exposure to Pb, Hg and PCB-153 was estimated in cord blood samples at birth, and in
• blood samples at 11 years old and at time of testing. Bayesian Kernel Machine Regression and
• data for all environmental contaminant cord blood samples and 2) missing data for all
• Our main exposure variables (Pb, Hg and PCBs) were collected at three time points. Prenatal
• exposure to Pb, Hg and PCBs were estimated by collecting blood samples (30 mL) from
• Pb, Hg and PCBs exposures were obtained from a venous blood sample (20 mL) during the
• exposures were obtained from venous blood sample (30 mL) the day preceding testing of
• blood samples were estimated using graphite furnace atomic absorption spectroscopy with
• plasma mass spectrometry (ICP-MS) was used for child blood samples (PerkinElmer
• Sciex Elan 6000). Cold vapor atomic absorption spectrometry was used to measure total
• blood samples (Pharmacia Model 120) and ICP-MS was used for the child blood samples
• samples were measured using ICP-MS (PerkinElmer ELAN DRC II). Concentrations of
• docosahexaenoic acid (DHA) were also collected at all time points and estimated from the
• same blood samples as the environmental contaminants. Concentrations of docosahexaenoic
• limits of detection (LODs) in cord samples were 0.02 μg/dL for Pb and Hg, 0.71 μg/dL for
• Se, and 0.02 μg/L for all PCB congeners. LODs in postnatal blood samples were 0.01 μg/dL
• et al., 2014; Muckle et al., 2001). DHA cord and child samples were analyzed at the Lipid
• Analytical Laboratory of Guelph University and DHA adolescent samples were analyzed at

Implications

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Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Mercury
• Mercury
• Cadmium
• Lead

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Update history

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