Sex-Dependent Impact of Low-Level Lead Exposure during Prenatal Period on Child Psychomotor Functions

Abstract

The impact of exposure to lead on child neurodevelopment has been well established. However, sex differences in vulnerability are still not fully explained. We aimed at evaluating the effect of a low-level lead exposure, as measured between 20 to 24 weeks of pregnancy and in cord blood, on developmental scores up to 24 months of age in 402 children from the Polish Mother and Child Cohort (REPRO_PL). Additionally, sex-dependent susceptibility to lead at this very early stage of psychomotor development was assessed. The blood lead levels were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). In order to estimate the children’s neurodevelopment, the Bayley Scales of Infant and Toddler Development was applied. The geometric mean (GM) for blood lead level during 20–24 weeks of pregnancy was 0.99 ± 0.15 µg/dL and, in the cord blood, it was 0.96 ± 0.16 µg/dL. There was no statistically significant impact of lead exposure during prenatal period on the girls’ psychomotor abilities. Among the boys, we observed lower scores for cognitive functions, along with increasing cord blood lead levels (β = −2.07; p = 0.04), whereas the results for the language and motor abilities were not statistically significant (p > 0.05). Our findings show that fetal exposure to very low lead levels might affect early cognitive domain, with boys being more susceptible than girls. Education on health, higher public awareness, as well as intervention programs, along with relevant regulations, are still needed to reduce risks for the vulnerable population subgroups.

In Utero Exposure to Aluminium and Other Neurotoxic Elements in Urban Coastal South African Women at Delivery: An Emerging Concern

“…For female neonates, some negative associations were evident between Al levels in serum and Hg and As concentrations in whole blood, but these were not significant. In support of the findings of our study showing a sex-dependent association for Pb exposure in neonates, another study showed that foetal exposure to very low Pb levels may affect early cognitive domain, with boys being more susceptible than girls [62]. The latter study investigated the effect of a low-level Pb exposure, as measured between 20 to 24 weeks of pregnancy and in cord blood, on developmental scores up to 24 months of age in a group of children from the Polish Mother and Child Cohort.…”

Sex-Dependent Effects of Developmental Lead Exposure in Wistar Rats: Evidence from Behavioral and Molecular Correlates

“…Concomitant with the USV recording, the spontaneous movements of the pups were also videotaped. In accordance with previous studies focused on neonatal rodent behavior [91], the following behavioral patterns were scored: locomotion (general translocation of the body of at least 1 cm in the glass container), immobility (no visible movement of the animal when placed with all the four paws on the floor), head rising (a single rising of the head up and forward), face washing (forepaws moving back and forth from the ears to the snout and mouth), wall climbing (alternating forelimb placing movements on the wall of the container), pivoting (locomotor activity involving the front limbs alone and resulting in laterally directed movements), and curling (roll, vigorous side-to-side rolling movements while on the back; curl, a convex arching of back while on side or back, bringing head in a closer opposition to hump/hindlimb region).…”

“…Overall, our behavioral and molecular data indicate more pronounced effects in females than males developmentally exposed to Pb, which by interfering with biochemical trajectories linked to the maturation of the excitatory circuits early in life may set the stage for behavioral alterations later in life. Of note, in epidemiological studies where sex effects were examined, adverse outcomes from developmental Pb exposures have been described more frequently in males than in females [35,36,90,91] in contrast to experimental findings. However, it has to be noted that the influence of sex/gender on outcomes may depend on the type of outcomes measured, the age of outcome assessment and, last but not least from the statistical methods applied.…”

Sex-specific associations between co-exposure to multiple metals and visuospatial learning in early adolescence

“…Other studies have also reported associations between higher metal levels and worse cognitive and behavioral outcomes in girls [53][54][55][56][57] . Metal-related neurodevelopmental outcomes have been also reported in boys [58][59][60][61][62][63] . Our results correspond with previous studies, suggesting that male and female neurodevelopment is not equally vulnerable to the effect of metal exposure.…”