Toxics (Pb, Cd) and trace elements (Zn, Cu, Mn) in women during pregnancy and at delivery, South Benin, 2014-2015

The Relationship Between Heavy Metals and Missed Abortion: Using Mediation of Serum Hormones

Accumulating evidence suggests that heavy metal exposure may have adverse effects on the fetal development. Furthermore, disruption of serum hormone homeostasis can result in the adverse pregnancy outcomes. Therefore, this study aimed to investigate the potential association between heavy metals and missed abortion, with a focus on whether serum hormones mediate this relationship. The concentrations of heavy metals and hormones in serum were measured in this case-control study. Statistical models including, logistic regression model, principal component analysis (PCA), and weighted quantile sum (WQS) regression model were employed to examine the relationship between heavy metals, serum hormones, and missed abortion. Furthermore, the mediation analysis was performed to assess the role of serum hormones as potential mediators in this relationship. This study revealed significant associations between heavy metal exposure and missed abortion. Notable, the WQS index weight, which was mainly influenced by copper (Cu) and zine (Zn), is associated with missed abortion. Moreover, heavy metals including manganese (Mn), nickel (Ni), Zn, arsenic (As), Cu, cadmium (Cd), and lead (Pb) were found to be associated with serum levels of β-human chorionic gonadotropin (β-hCG), progesterone (P), estradiol (E2), and lactogen (HPL). In addition, the mediation analysis indicated that β-hCG explained a portion of the association (ranging from 18.77 to 43.51%) of between Mn, Ni, Zn, and As exposure and missed abortion. Serum P levels explained 17.93 to 51.70% of the association between Ni, Cu, and As exposure and missed abortion. Serum E2 levels played a significant mediating role, explaining a portion of the association (ranging from 22.14 to 73.60%) between Mn, Ni, Cu, As, Cd, and Pb exposure and missed abortion. Our results suggested that β-hCG, P, and E2 are one of the potential mediators in the complex relationship between heavy metals exposure and missed abortion. These results highlight the importance of considering both heavy metal exposure and serum hormone levels in understanding the etiology of missed abortion.

Role of mineral nutrients other than iron in pregnancy: under recognized opportunities to improve maternal/fetal outcomes: a literature review

BACKGROUND

Anemia during pregnancy is an important global health concern, affecting 40% of women worldwide, and iron deficiency shares a significant proportion of the burden. From conception to birth, pregnancy is a period when women undergo metabolic and physiological changes. The nutritional needs are higher during pregnancy; thus, adequate nutrition is essential to maintain fetal growth and development. However, adverse effects due to deficiency in nutrition during pregnancy can result in maternal, fetal and neonatal complications. Despite the multifactorial etiology of anemia, iron deficiency is assumed as the primary cause of anemia during pregnancy and hence, mitigation strategy pivots around it for anemia management. Therefore, excluding other contributors, a single-micronutrient approach with iron supplements remains a myopic approach and this can exacerbate iron deficiency anemia. Micronutrient deficiencies are of particular concern as they may pose a silent threat to the survival and well-being of reproductive-age women and their infants.

AIM

Micronutrients, especially trace minerals, play a myriad of roles in pregnancy, and the lack of each one causes adverse complications to both the mother and the fetus. In this review paper, we attempt to piece together available information regarding the adverse effects of abnormal trace mineral levels along with iron deficiency on the mother and the fetus.

METHOD

A non-systematic literature search in PubMed, Google Scholar, and the Cochrane databases, for publications on minerals and vitamins during pregnancy and the possible influence of supplements on pregnancy outcomes.

CONCLUSION

Micronutrient deficiency exacerbates the pregnancy-induced anemia and other adverse birth outcomes. Micronutrient supplementation during pregnancy can combat anemia as well as reduce a number of adverse pregnancy outcomes in a comprehensive manner.

Recent advances and future perspective on lignocellulose-based materials as adsorbents in diverse water treatment applications

The growing shortage of non-renewable resources and the burden of toxic pollutants in water have gradually become stumbling blocks in the path of sustainable human development. To this end, there has been great interest in finding renewable and environmentally friendly materials to promote environmental sustainability and combat harmful pollutants in wastewater. Of the many options, lignocellulose, as an abundant, biocompatible and renewable material, is the most attractive candidate for water remediation due to the unique physical and chemical properties of its constituents. Herein, we review the latest research advances in lignocellulose-based adsorbents, focusing on lignocellulosic composition, material modification, application of adsorbents. The modification and preparation methods of lignin, cellulose and hemicellulose and their applications in the treatment of diverse contaminated water are systematically and comprehensively presented. Also, the detailed description of the adsorption model, the adsorption mechanism and the adsorbent regeneration technique provides an excellent reference for understanding the underlying adsorption mechanism and the adsorbent recycling. Finally, the challenges and limitations of lignocellulosic adsorbents are evaluated from a practical application perspective, and future developments in the related field are discussed. In summary, this review offers rational insights to develop lignocellulose-based environmentally-friendly reactive materials for the removal of hazardous aquatic contaminants.

Early-life manganese exposure during multiple developmental periods and adolescent verbal learning and memory

BACKGROUND

Manganese (Mn) is both an essential and toxic metal, and associations with neurodevelopment depend on exposure timing. Prospective data examining early life Mn with adolescent cognition are sparse.

METHODS

We enrolled 140 Italian adolescents (10-14 years old) from the Public Health Impact of Metals Exposure study. Mn in deciduous teeth was measured using laser ablation-mass spectrometry to represent prenatal, postnatal and early childhood exposure. The California Verbal Learning Test for Children (CVLT-C) was administered to assess adolescent verbal learning and memory. Multivariable regression models estimated changes in CVLT-C scores and the odds of making an error per doubling in dentine Mn in each exposure period. Multiple informant models tested for differences in associations across exposure periods.

RESULTS

A doubling in prenatal dentine Mn levels was associated with lower odds of making an intrusion error (OR = 0.23 [95% CI: 0.09, 0.61]). This beneficial association was not observed in other exposure periods. A doubling in childhood Mn was beneficially associated with short delay free recall: (ß = 0.47 [95% CI: -0.02, 0.97]), which was stronger in males (ß = 0.94 [95% CI: 0.05, 1.82]). Associations were null in the postnatal period.

CONCLUSION

Exposure timing is critical for understanding Mn-associated changes in cognitive function.

Determinants of Exposure to Potentially Toxic Metals in Pregnant Women of the DSAN-12M Cohort in the Recôncavo Baiano, Brazil

Exposure to potentially toxic metals (PTM) threatens maternal and child health. We investigated the determinants of exposure to lead (Pb), cadmium (Cd), arsenic (As), and manganese (Mn) in 163 pregnant women from the Recôncavo Baiano, Brazil, enrolled in the DSAN-12M cohort. We measured these metals in biological samples (blood, toenails, and hair) and the Pb dust loading rates (RtPb) at their homes by graphite furnace atomic absorption spectrophotometry (GFAAS). Questionnaires were applied to collect sociodemographic and general habits data. Only 2.91% (n = 4) of the pregnant women had As levels above the detection limit. Few participants had levels above the recommended reference values for blood Pb (5.1; 95% CI: 2.1-10.1%), and Mn in hair or toenails (4.3; 95% CI: 2.3-10.1%). On the other hand, 61.1 (95% CI: 52.4-69.3%) had elevated blood Cd levels. After binary logistic regression, low socioeconomic status, domestic waste burning, being a passive smoker, multiparity, and renovating the house significantly increased the chances of having high levels of Mn, Pb, and Cd. We detected a worrying situation related to exposure to Cd, showing the urgency of implementing human biomonitoring in the general population, especially in situations of social vulnerability.

The versatility of nanocellulose, modification strategies, and its current progress in wastewater treatment and environmental remediation

Deterioration in the environmental ecosystems through the depletion of nonrenewable resources and the burden of deleterious contaminants is considered a global concern. To this end, great interest has been shown in the use of renewable and environmentally-friendly reactive materials dually to promote environmental sustainability and cope with harmful contaminants. Among the different available options, the use of nanocellulose (NC) as an environmentally benign and renewable natural nanomaterial is an attractive candidate for environmental remediation owing to its miraculous physicochemical characteristics. This review discusses the intrinsic properties and the structural aspects of different types of NC, including cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs), and bacterial cellulose (BC) or bacterial nanocellulose (BNC). Also, the different modification strategies involving the functionalization or hybridization of NC by using different functional and reactive materials aimed at wastewater remediation have been elaborated. The modified or hybridized NC has been explored for its applications in the removal or degradation of aquatic contaminants through adsorption, filtration, coagulation, catalysis, photocatalysis, and pollutant sensing. This review highlights the role of NC in the modified composites and describes the underlying mechanisms involved in the removal of contaminants. The life-cycle assessment (LCA) of NC is discussed to unveil the hidden risks associated with its production to the final disposal. Moreover, the contribution of NC in the promotion of waste management at different stages has been described in the form of the five-Rs strategy. In summary, this review provides rational insights to develop NC-based environmentally-friendly reactive materials for the removal and degradation of hazardous aquatic contaminants.

Plasma Manganese Levels and Risk of Gestational Diabetes Mellitus: A Prospective Cohort Study

Manganese (Mn) intake has been found to be linked with risk of type 2 diabetes. However, the role of Mn in the development of gestational diabetes mellitus (GDM) remains to be investigated. This prospective study included pregnant women from the Tongji Maternal and Child Health Cohort. A total of 2327 participants with plasma specimens before 20 weeks were included. Among the pregnant women, 9.7% (225/2327) were diagnosed with GDM. After adjustment, pregnant women with the third and highest quartile of plasma Mn levels had 1.31-fold (RR, 2.31 [1.48, 3.61]) and 2.35-fold (RR, 3.35 [2.17, 5.17]) increased risk of GDM compared with those with the lowest quartile. A 1 standard deviation increment of ln-transformed plasma Mn levels (0.53 μg/L) was related to elevated risks of GDM with RRs of 1.28 [1.17, 1.40]. The positive associations between Mn and GDM remained consistent in all the subgroups. The weighted quantile sum index was significantly related to GDM (RR, 1.60 [1.37, 1.86]). The contribution of Mn (58.69%) to the metal mixture index was the highest related to GDM. Higher plasma Mn levels were found to be linked with elevated fasting and 2 h post-load blood glucose. This study revealed relationships of higher plasma Mn levels in early pregnancy and increased risk of GDM, suggesting that though essential, excess Mn in the body might be a potential important risk factor for GDM.

Maternal and fetal exposure to metal (loid)s, maternal nutrition status, and impact on prenatal growth in an energy rich zone and an urban area along the Persian Gulf

The main purposes of the study were to determine whether maternal and cord blood (MB and CB) levels of metal (loid)s (MLs) are different between industrial and urban areas. Subjects were derived from the petrochemical and gas area (PGA) of Asaluyeh County and the urban area (UA) of Bushehr County in Iran. Adjusted models revealed significant differences between the PGA and UA for maternal Fe, Cu, Mg, Cd, Zn, Ni, V and Pb levels, likewise cord Cu, V, Pb and Ni levels, which were higher in the PGA. Unadjusted models revealed there were decreases in neonatal weight and head circumference by 16.550 g and 0.059 cm, respectively for each Ln unit increase in maternal Cr levels. The mean blood levels of MLs significantly associated with food consumption frequency. The MLs were detected at higher levels in the body's fetuses and their mothers who resided in the PGA than those from the UA. So, the fetuses of mothers living in an industrial areas may be at higher risk from anthropometric measures. The impact of prenatal exposure to MLs on prenatal growth should be considered for better understanding in the further studies.

Gender differences in trace element exposures with cognitive abilities of school-aged children: a cohort study in Wujiang city, China

Trace elements persist in the environment, and their early exposure may adversely affect children's intellectual development. To clarify the influence of blood trace element levels in newborns and school-aged children, we used Wechsler Intelligence Scale for children (WISC-CR) to explore intellectual development level of 148 school-aged children based on a population cohort study. Lead (Pb), selenium (Se), arsenic (As), copper (Cu), manganese (Mn) and chromium (Cr) in cord blood and Pb, As, Cu in venous blood were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometer (AAS). Our analysis of the correlation between children's mental development and trace element content found children's cognitive abilities negatively correlate with Pb (PIQ: β=-0.109, P=0.03737) and Cu (PIQ: β=-0.031, P=0.04431; FISQ: β=-0.031, P=0.02137) levels in cord blood. Prenatal low-level As exposure may negatively affect girls' performance intelligence quotient (PIQ) and verbal intelligence quotient (VIQ). There were differences in Se levels in cord blood and venous blood between boys and girls (P=0.010; P=0.073). High Se levels were associated with a lower VIQ in boys and a higher VIQ in girls. Prenatal exposure to Pb, As and Cu may weaken children's cognitive abilities at school age. Se exposure may have opposite effects on cognitive abilities affected by dose and gender.

Maternal Blood Levels of Toxic and Essential Elements and Birth Outcomes in Argentina: The EMASAR Study

Pregnant women’s levels of toxic and essential minerals have been linked to birth outcomes yet have not been adequately investigated in South America. In Argentina, n = 696 maternal whole blood samples from Ushuaia (n = 198) and Salta (n = 498) were collected in 2011–2012 among singleton women at 36 ± 12 h postpartum and analyzed for blood concentrations of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), manganese (Mn), selenium (Se) and zinc (Zn). This study examined the associations between maternal elements levels and birth outcomes, and sociodemographic factors contributing to elements levels. Maternal age, parity, body mass index, smoking, and education were linked to concentrations of some but not all elements. In adjusted models, one ln-unit increase in Pb levels was associated with increased gestational age (0.2 weeks, 95% CI = 0.01–0.48) and decreased birth weight (−88.90 g, 95% CI = −173.69 to −4.11) and birth length (−0.46 cm, 95% CI = −0.85 to −0.08) in the Salta sample. Toxic elements concentrations were not associated with birth outcomes in Ushuaia participants. Birth outcomes are multifactorial problems, and these findings provide a foundation for understanding how the body burden of toxic and essential elements, within the socioeconomic context, may influence birth outcomes.

The associations of serum metals concentrations with the intermediate and pregnancy outcomes in women undergoing in vitro fertilization (IVF)

BACKGROUND

Toxic and essential trace elements are reported to have impact on female fertility. However, studies on the potential synergistic or antagonistic effects of metal mixtures on IVF outcomes remain limited.

OBJECTIVE

To evaluate whether serum concentrations of metals, individually and as mixtures, are associated with pregnancy outcomes in women undergoing IVF.

METHODS

In a prospective birth cohort study about IVF from the First Affiliated Hospital of Anhui Medical University (n = 1184), we measured the concentrations of serum metals by ICP-MS according to a previously established method. Oocyte/embryo development indicators and follow-up results were also collected. The individual and joint effects of metals were estimated using logistic regressions and Bayesian kernel machine regressions (BKMR).

RESULTS

At embryonic stage, we found negative associations between the serum lead (Pb) (β = -0.14, 95%CI: -0.32, -0.04) and cadmium (Cd) (β = -0.24, 95%CI: -0.39, -0.09) concentrations and the high-quality embryos rate; and positive associations between the serum cobalt (Co) (β = 0.18, 95%CI: 0.05, 0.31) and selenium (Se) (β = 0.17, 95%CI: 0.06, 0.41) concentrations and the MII rate. Regarding to the pregnancy outcomes, the serum Pb was negatively related with successful implantation (OR=0.85, 95%CI: 0.77, 0.94) and clinical pregnancy (OR=0.95, 95%CI: 0.91, 0.99); and positively associated with spontaneous abortion (OR=1.39, 95% CI: 1.02, 1.91). The BKMR analysis showed linear or parabolic associations between the metal mixtures and pregnancy outcomes, with Pb showing the highest posterior inclusion probabilities.

CONCLUSIONS

The toxic (Pb, Cd) and essential (Co, Se) metals could be incorporated as simultaneous predictors of IVF outcomes including potential antagonistic effects, in which Pb exhibits major contributions.

Recent advances on nanocellulose biomaterials for environmental health photoremediation: An overview

As one of the potential bionanomaterials, nanocellulose has appeared as a favorable candidate for photoremediation of the environment because of its abundance in nature, inexpensive, eco-friendly, decomposable, high surface area, and outstanding mechanical properties. The current review carefully summarized the diverse type of nanocellulose, their preparation approaches, and several previous works on the use of nanocellulose for photoremediation. These include the role of nanocellulose for the increased surface active site of the hybrid photocatalysts by providing a large surface area for enhanced adsorption of photons and pollutant molecules, as a dispersing agent to increase distribution of metal/non-metal dopants photocatalysts, as well as for controlled size and morphology of the dopants photocatalysts. Furthermore, the recommendations for upcoming research provided in this review are anticipated to ignite an idea for the development of other nanocellulose-based photocatalysts. Other than delivering beneficial information on the present growth of the nanocellulose biomaterials photocatalysts, this review is expected will attract more interest to the utilization of nanocellulose photocatalyst and distribute additional knowledge in this exciting area of environmental photoremediation. This could be attained by considering that a review on nanocellulose biomaterials for environmental health photoremediation has not been described elsewhere, notwithstanding intensive research works have been dedicated to this topic.

Pre-conception serum ferritin concentrations are associated with metal concentrations in blood during pregnancy: A cohort study in Benin

BACKGROUND

Iron deficiency is a common nutritional deficiency that impacts maternal health and fetal development and is also associated with increased uptake of toxic metals. Women in sub-Saharan Africa are highly exposed to both iron deficiency and metals in the environment. As research on the developmental origins of health and disease increasingly shows impacts of pre-conception maternal health on pregnancy and fetal health, these environmental exposures are of concern.

OBJECTIVES

This study investigated the association between iron status pre-pregnancy and blood metal concentrations in the first trimester of pregnancy with potential implications for iron supplementation.

METHODS

Pre-conception and first trimester blood samples taken from 262 Beninese women were tested for serum ferritin, inflammation markers, manganese (Mn), cadmium (Cd), lead (Pb), copper, zinc, selenium, mercury and arsenic. Associations between serum ferritin adjusted for inflammation and metal concentrations were analyzed using multivariate linear regression.

RESULTS

Women with iron deficiency before conception (13%) were more likely to remain iron deficient in the first trimester (4%) (adjusted OR = 41.2, 95%CI 6.2; 275.0) even within the context of routine iron supplementation during pregnancy. Lower pre-pregnancy serum ferritin concentrations were significantly related to higher concentrations of Mn, Cd and Pb in the first trimester. Every 1% increase in serum ferritin concentration was associated with a 0.13% decrease in Mn (adjusted β = -0.13, 95%CI -0.18; -0.07), a 0.22% decrease in Cd (adjusted β = -0.22, 95%CI -0.28; -0.15) and a 0.06% decrease in Pb concentration (adjusted β = -0.06, 95%CI -0.12; -0.006).

DISCUSSION

These results suggest that increasing iron stores prior to pregnancy may prevent excessive uptake of toxic concentrations of the metals Mn, Cd and Pb and argue in favour of testing the effects of iron supplementation prior to pregnancy on metal concentrations.

Associations between prenatal exposure to cadmium and lead with neural tube defect risks are modified by single-nucleotide polymorphisms of fetal MTHFR and SOD2: a case-control study

BACKGROUND

Prenatal exposure to heavy metals is implicated in the etiology of birth defects. We investigated whether concentrations of cadmium (Cd) and lead (Pb) in umbilical cord tissue are associated with risk for neural tube defects (NTDs) and whether selected genetic variants of the fetus modify their associations.

METHODS

This study included 166 cases of NTD fetuses/newborns and 166 newborns without congenital malformations. Umbilical cord tissue was collected at birth or elective pregnancy termination. Cd and Pb concentrations were assessed by inductively coupled plasma-mass spectrometry, and 20 single-nucleotide polymorphisms (SNPs) in 9 genes were genotyped. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the risk for NTDs in association with metal concentrations or genotype using logistic regression. Multiplicative-scale interactions between the metals and genotypes on NTD risk were assessed with logistic regression, and additive-scale interactions were estimated with a non-linear mixed effects model.

RESULTS

Higher concentrations of Cd were observed in the NTD group than in the control group, but no difference was found for Pb. Concentrations of Cd above the median level showed a risk effect, while the association between Pb and NTD risk was not significant in univariate analyses. The association of Cd was attenuated after adjusting for periconceptional folic acid supplementation. Fetuses with the AG and GG genotypes of rs4880 in SOD2 (superoxide dismutase 2) tended to have a lower risk, but fetuses with the CT and TT genotypes of rs1801133 in MTHFR (5,10-methylenetetrahydrofolatereductase) have a higher risk for NTDs when compared to their respective wild-type. rs4880 and Cd exhibited a multiplicative-scale interaction on NTD risk: the association between higher Cd and the risk for NTDs was increased by over fourfold in fetuses carrying the G allele [OR 4.43 (1.30-15.07)] compared to fetuses with the wild-type genotype. rs1801133 and Cd exposure showed an additive interaction, with a significant relative excess risk of interaction [RERI 0.64 (0.02-1.25)].

CONCLUSIONS

Prenatal exposure to Cd may be a risk factor for NTDs, and the risk effect may be enhanced in fetuses who carry the G allele of rs4880 in SOD2 and T allele of rs1801133 in MTHFR.

Assessment of 12 Essential and Toxic Elements in Whole Blood of Pregnant and Non-pregnant Women Living in Wuhan of China

Exposures to toxic trace elements and deficiencies of essential elements during pregnancy are associated to various birth complications. Assessment of the trace elements in pregnant women living in specific areas is important for biomonitoring. A total of 196 healthy pregnant women absent of pregnancy complications living in Wuhan of China and 210 healthy non-pregnant women were enrolled. The whole blood were collected. The toxic element chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), thallium (Tl), and lead (Pb) and essential elements magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) were determined by using a inductively coupled plasma mass spectrometry (ICP-MS)-based method. All the metal(loid)s, except for Cd, Hg, and Tl, showed different levels in whole blood of the pregnant women compared with the non-pregnant women (p < 0.05), among which Mg, Fe, As, and Pb were lower while Ca, Cr, Mn, Cu, and Zn were higher. Moreover, whole blood levels of Mg, Mn, Fe, Cu, and Zn showed significant variations among different gestational ages, while As and Cd showed significant variations among different maternal ages. In addition, Fe-Mg, Fe-Zn, Cu-Ca, and Hg-As were found to be correlated positively in whole blood of the pregnant women, while Fe-Ca, Zn-Ca, and Fe-Cu were correlated negatively. The systematic information of toxic and essential elements in whole blood of pregnant women living in Wuhan of China can provide important guidance for the supplementation of essential elements during pregnancy and for biomonitoring of environmental overexposure.

Follow-Up of Elevated Blood Lead Levels and Sources in a Cohort of Children in Benin

Lead exposure is associated with poor cognitive development in children. Very few studies in sub-Saharan Africa (SSA) have studied blood lead levels (BLLs) and non-gasoline sources of exposure in children. Data from a birth cohort in Benin (2011-2013) suggested that 58% of 1-year-old children had BLLs > 50 ug/L. We aimed to investigate the prevalence of elevated BLLs (>50 µg/L and >100 µg /L) among 425 of these children at 6 years of age in 2016-2018 and to compare BLLs between age 1 and 6 years, and study sources of lead at age 6 years. BLLs were analysed by inductively coupled plasma mass spectrometry. Multiple linear regression and quantile regressions were used to study potential sources of lead. The prevalence of BLLs > 50 µg/L in children was 59.5% (Geometric Mean (GM) 56.4 µg/L, 95% CI: 54.1-58.7) at 6 years of age compared to 54.8% (GM 56.5 µg/L, 95% CI: 53.4-59.6) at 1 year of age. The prevalence of children with BLLs > 100 µg/L decreased from 14.4% at 1 year of age to 8.2% at 6 years of age. After adjustment for all other covariates, consumption of peanuts more than once per month was significantly associated with a 22.0% (95% CI: 4.6, 42.5) increment in BLLs at age 6 years compared with no consumption. Consumption of bushmeat killed by lead bullets at age 6 years was associated with an increase in the higher percentiles of BLLs (P75) compared with the absence of this source. Other potential sources of lead associated with BLLs with marginal significance were consumption of rice, paternal occupational exposure, and the presence of activity with the potential use of lead. This prospective cohort confirms the persistently high prevalence of elevated BLLs in children residing in a rural region in the south of Benin, as well as the presence of multiple and continuous sources of lead. These results highlight the need for prevention programs to reduce and eliminate lead exposure in children.

Blood manganese levels during pregnancy and postpartum depression: A cohort study among women in Mexico

BACKGROUND

Occupational studies have shown an association between elevated Mn exposure and depressive symptoms. Blood Mn (BMn) naturally rises during pregnancy due to mobilization from tissues, suggesting it could contribute to pregnancy and postpartum depressive symptoms.

OBJECTIVES

To assess the association between BMn levels during pregnancy and postpartum depression (PPD), creating opportunities for possible future interventions.

METHODS

We studied 561 women from the reproductive longitudinal Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) cohort in Mexico City. BMn was measured at the 2nd and 3rd trimesters, as well as delivery. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess PPD symptoms at 12-months postpartum. We used a generalized linear model assuming a Poisson distribution to assess the association between BMn levels and PPD, with adjustments for age, stress and depressive symptoms during pregnancy, education, socioeconomic status, and contemporaneous blood lead levels.

RESULTS

The mean ± standard deviation (SD) EPDS score at 12-months postpartum was 6.51 ± 5.65, and 17.11% of women met the criteria for possible PPD (score ≥ 13). In adjusted models, BMn during the 3rd trimester (β: 0.13, 95% CI: 0.04-0.21) and BMn levels averaged at the 2nd and 3rd trimester (β: 0.14, 95% CI: 0.02-0.26) had a positive association with EPDS scores at 12 months postpartum. BMn at the 2nd trimester (β: 0.07, 95% CI: -0.09-0.22) and delivery (β: 0.03, 95% CI: -0.04-0.10) had a non-significant positive association with EPDS scores at 12-months postpartum. Stress and depressive symptoms during pregnancy was associated with higher EPDS scores at 12-months postpartum in all of the adjusted models but were only significant when either BMn during 3rd trimester or BMn averaged across 2nd and 3rd trimester was assessed as the exposure.

DISCUSSION

Our results demonstrate that elevated BMn levels during pregnancy predict PPD symptoms and could be a potential pathway for intervention and prevention of PPD.