Dataset Information

Maternal PUFA status but not prenatal methylmercury exposure is associated with children's language functions at age five years in the Seychelles.

ABSTRACT: Evidence from the Seychelles Child Development Nutrition Study suggests that maternal nutritional status can modulate the relationship between prenatal methylmercury (MeHg) exposure and developmental outcomes in children. The aim of this study was to investigate whether maternal PUFA status was a confounding factor in any possible associations between prenatal MeHg exposure and developmental outcomes at 5 y of age in the Republic of Seychelles. Maternal status of (n-3) and (n-6) PUFA were measured in serum collected at 28 wk gestation and delivery. Prenatal MeHg exposure was determined in maternal hair collected at delivery. At 5 y of age, the children completed a comprehensive range of sensitive developmental assessments. Complete data from 225 mothers and their children were available for analysis. Multiple linear regression analyses revealed Preschool Language Scale scores of the children improved with increasing maternal serum DHA [22:6(n-3)] concentrations and decreased with increasing arachidonic acid [20:4(n-6)] concentrations, albeit verbal intelligence improved with increasing (n-6) PUFA concentrations in maternal serum. There were no adverse associations between MeHg exposure and developmental outcomes. These findings suggest that higher fish consumption, resulting in higher maternal (n-3) PUFA status, during pregnancy is associated with beneficial developmental effects rather than detrimental effects resulting from the higher concomitant exposures of the fetus to MeHg. The association of maternal (n-3) PUFA status with improved child language development may partially explain the authors' previous finding of improving language scores, as prenatal MeHg exposure increased in an earlier mother-child cohort in the Seychelles where maternal PUFA status was not measured.

SUBMITTER: Strain JJ

PROVIDER: S-EPMC3498972 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Maternal PUFA status but not prenatal methylmercury exposure is associated with children's language functions at age five years in the Seychelles.

Strain J J JJ Davidson Philip W PW Thurston Sally W SW Harrington Donald D Mulhern Maria S MS McAfee Alison J AJ van Wijngaarden Edwin E Shamlaye Conrad F CF Henderson Juliette J Watson Gene E GE Zareba Grazyna G Cory-Slechta Deborah A DA Lynch Miranda M Wallace Julie M W JM McSorley Emeir M EM Bonham Maxine P MP Stokes-Riner Abbie A Sloane-Reeves Jean J Janciuras Joanne J Wong Rosa R Clarkson Thomas W TW Myers Gary J GJ

The Journal of nutrition 20120926 11

Evidence from the Seychelles Child Development Nutrition Study suggests that maternal nutritional status can modulate the relationship between prenatal methylmercury (MeHg) exposure and developmental outcomes in children. The aim of this study was to investigate whether maternal PUFA status was a confounding factor in any possible associations between prenatal MeHg exposure and developmental outcomes at 5 y of age in the Republic of Seychelles. Maternal status of (n-3) and (n-6) PUFA were measur ...[more]

PMID: 23014496

Similar Datasets

Project description:The aim of this study was to determine if prenatal or recent postnatal methylmercury (MeHg) exposure from consuming ocean fish and seafood is associated with auditory deficits in young adults. Some investigators have reported adverse associations while others have found no associations. Ocean fish is an important nutrient source for billions of people around the world. Consequently, determining if there is an adverse association with objective auditory measures is important in assessing whether a risk is present or not.The peripheral and central auditory function of 534 subjects in the Seychelles Child Development Study (SCDS) Main Cohort was examined at age of 19 years. The auditory test battery included standard pure-tone audiometry, tympanometry, auditory brainstem response (ABR) latencies, and both click-evoked and distortion product otoacoustic emissions (OAE). Associations with MeHg were evaluated with multiple linear regression models, adjusting for sex, recent postnatal MeHg exposure, and hearing loss.Bilateral hearing loss (defined as a mean pure-tone threshold of greater than 25 dB) was present in 1.1%of the subjects and was not associated with prenatal or recent postnatal MeHg exposure. As expected, absolute and interwave ABR latencies were shorter for women as compared to men, as the stimulus presentation rate decreased from 69.9 to 19.9 clicks/s and as the stimulus intensity increased from 60 to 80 dBnHL. Similarly, larger OAE amplitudes were elicited in women as compared to men and in the right ears as compared to the left. There was no association of prenatal MeHg exposure with hearing loss, ABR absolute and interwave latencies or OAE amplitudes. As recent postnatal MeHg increased, some associations were found with a few ABR absolute and interwave latencies and a few OAE amplitudes. However, the direction of these associations was inconsistent. As recent postnatal MeHg levels increased the wave I absolute latencies were shorter at 80 dBnHL for all three click rates, but the interwave I–V latency was longer for males for the 80 dBnHL 19 clicks/s and for the III–V interwave latencies for males and females for the dBnHL 69 clicks/s. Similarly, smaller OAE amplitudes were found at 1500, 2000, and 4000 Hz for males while larger OAE amplitudes were found for females at 1500 and 2000 Hz as the recent postnatal MeHg levels increased.No consistent associations were present in this study between prenatal MeHg exposure from consumption of oceanic fish and seafood during pregnancy and auditory functions at 19 years of age. Given the level of prenatal exposure to MeHg, the number of audiologic measures tested, and the presence of the expected sex, click rate, and level dependent findings, it seems unlikely that an association was present and not detected. As recent postnatal MeHg exposure increased, a few associations with ABR latencies and OAE amplitudes were found. The direction of these associations was inconsistent as some showed improved performance as MeHg exposure levels increased while others showed poorer performance. The presence of the inconsistent postnatal MeHg exposure findings are intriguing and deserve further clarification.

Project description:BackgroundFish is a primary source of protein and n-3 PUFA but also contains methylmercury (MeHg), a naturally occurring neurotoxicant to which, at sufficient exposure levels, the developing fetal brain is particularly sensitive.ObjectivesTo examine the association between prenatal MeHg and maternal status of n-3 and n-6 PUFA with neurodevelopment, and to determine whether PUFA might modify prenatal MeHg associations with neurodevelopment.MethodsWe examined the Seychelles Child Development Study Nutrition Cohort 2 (NC2) at age 7 y. We used a sophisticated and extensive neurodevelopmental test battery that addressed 17 specific outcomes in multiple neurodevelopmental domains: cognition, executive and psychomotor function, language development, behavior, scholastic achievement, and social communication. Analyses were undertaken on 1237 mother-child pairs with complete covariate data (after exclusions) and a measure of at least 1 outcome. We examined the main and interactive associations of prenatal MeHg exposure (measured as maternal hair mercury) and prenatal PUFA status (measured in maternal serum at 28 weeks' gestation) on child neurodevelopmental outcomes using linear regression models. We applied the Bonferroni correction to account for multiple comparisons and considered P values <0.0029 to be statistically significant.ResultsPrenatal MeHg exposure and maternal DHA and arachidonic acid (20:4n-6) (AA) status were not significantly associated with any neurodevelopmental outcomes. Findings for 4 outcomes encompassing executive function, cognition, and linguistic skills suggested better performance with an increasing maternal n-6:n-3 PUFA ratio (P values ranging from 0.004 to 0.05), but none of these associations were significant after adjusting for multiple comparisons. No significant interaction between MeHg exposure and PUFA status was present.ConclusionsOur findings do not support an association between prenatal MeHg exposure or maternal DHA and AA status with neurodevelopmental outcomes at age 7 y. The roles of n-6 and n-3 PUFA in child neurodevelopment need further research.

Project description:Maternal consumption of fish during the gestational period exposes the fetus to both nutrients, especially the long-chain polyunsaturated fatty acids (LCPUFAs), believed to be beneficial for fetal brain development, as well as to the neurotoxicant methylmercury (MeHg). We recently reported that nutrients present in fish may modify MeHg neurotoxicity. Understanding the apparent interaction of MeHg exposure and nutrients present in fish is complicated by the limitations of modeling methods. In this study we fit varying coefficient function models to data from the Seychelles Child Development Nutrition Study (SCDNS) cohort to assess the association of dietary nutrients and children's development. This cohort of mother-child pairs in the Republic of Seychelles had fish consumption averaging 9 meals per week. Maternal nutritional status was assessed for five different nutritional components known to be present in fish (n-3 LCPUFA, n-6 LCPUFA, iron status, iodine status, and choline) and associated with children's neurological development. We also included prenatal MeHg exposure (measured in maternal hair). We examined two child neurodevelopmental outcomes (Bayley Scales Infant Development-II (BSID-II) Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI)), each administered at 9 and at 30 months. The varying coefficient models allow the possible interactions between each nutritional component and MeHg to be modeled as a smoothly varying function of MeHg as an effect modifier. Iron, iodine, choline, and n-6 LCPUFA had little or no observable modulation at different MeHg exposures. In contrast the n-3 LCPUFA docosahexaenoic acid (DHA) had beneficial effects on the BSID-II PDI that were reduced or absent at higher MeHg exposures. This study presents a useful modeling method that can be brought to bear on questions involving interactions between covariates, and illustrates the continuing importance of viewing fish consumption during pregnancy as a case of multiple exposures to nutrients and to MeHg. The results encourage more emphasis on a holistic view of the risks and benefits of fish consumption as it relates to infant development.

Project description:BackgroundMethylmercury (MeHg) is present in fish and is a neurotoxicant at sufficiently high levels. One potential mechanism of MeHg toxicity early in life is epigenetic dysregulation that may affect long-term neurodevelopment. Altered DNA methylation of nervous system-related genes has been associated with adult mental health outcomes.ObjectiveTo assess associations between prenatal MeHg exposure and DNA methylation (at the cytosine of CG dinucleotides, CpGs) in three nervous system-related genes, encoding brain-derived neurotropic factor (BDNF), glutamate receptor subunit NR2B (GRIN2B), and the glucocorticoid receptor (NR3C1), in children who were exposed to MeHg in utero.MethodsWe tested 406 seven-year-old Seychellois children participating in the Seychelles Child Development Study (Nutrition Cohort 2), who were prenatally exposed to MeHg from maternal fish consumption. Total mercury in maternal hair (prenatal MeHg exposure measure) collected during pregnancy was measured using atomic absorption spectroscopy. Methylation in DNA from the children's saliva was measured by pyrosequencing. To assess associations between prenatal MeHg exposure and CpG methylation at seven years of age, we used multivariable linear regression models adjusted for covariates.ResultsWe identified associations with prenatal MeHg exposure for DNA methylation of one GRIN2B CpG and two NR3C1 CpGs out of 12 total CpG sites. Higher prenatal MeHg was associated with higher methylation for each CpG site. For example, NR3C1 CpG3 had an expected increase of 0.03-fold for each additional 1 ppm of prenatal MeHg (B = 0.030, 95% CI 0.001, 0.059; p = 0.047). Several CpG sites associated with MeHg are located in transcription factor binding sites and the observed methylation changes are predicted to lead to lower gene expression.ConclusionsIn a population of people who consume large amounts of fish, we showed that higher prenatal MeHg exposure was associated with differential DNA methylation at seven years of age at specific CpG sites that may influence neurodevelopment and mental health.

Project description:BackgroundTelomere length (TL) and mitochondrial DNA copy number (mtDNAcn) variations are linked to age-related diseases and are associated with environmental exposure and nutritional status. Limited data, however, exist on the associations with mercury exposure, particularly early in life.ObjectiveWe examined the association between prenatal mercury (Hg) exposure and TL and mtDNAcn in 1,145 Seychelles children, characterized by a fish-rich diet.MethodsTotal mercury (THg) was determined in maternal hair at delivery and cord blood. TL and mtDNAcn were determined relative to a single-copy hemoglobin beta gene in the saliva of 7-y-old children. Linear regression models assessed associations between THg and relative TL (rTL) and relative mtDNAcn (rmtDNAcn) while controlling for maternal and cord serum polyunsaturated fatty acid (PUFA) status and sociodemographic factors. Interactions between THg and child sex, PUFA, and telomerase genotypes were evaluated for rTL and rmtDNAcn.ResultsHigher THg concentrations in maternal hair and cord blood were associated with longer rTL [β=0.009; 95% confidence interval (CI): 0.002, 0.016 and β=0.002; 95% CI: 0.001, 0.003, respectively], irrespective of sex, PUFA, or telomerase genotypes. Maternal serum n-6 PUFA and n-6/n-3 ratio were associated with shorter [β=-0.24; 95% CI: -0.33, -0.15 and β=-0.032; 95% CI: -0.048, -0.016, respectively] and n-3 PUFA with longer (β=0.34; 95% CI: 0.032, 0.65) rTL. Cord blood n-6 PUFA was associated with longer (β=0.15; 95% CI: 0.050, 0.26) rTL. Further analyses revealed linoleic acid in maternal blood and arachidonic acid in cord blood as the main drivers of the n-6 PUFA associations. No associations were observed for THg and PUFA with rmtDNAcn.DiscussionOur results indicate that prenatal THg exposure and PUFA status are associated with rTL later in childhood, although not consistently aligned with our initial hypothesis. Subsequent research is needed to confirm this finding, further evaluate the potential confounding of fish intake, and investigate the underlying molecular mechanisms to verify the use of rTL as a true biomarker of THg exposure. https://doi.org/10.1289/EHP14776.

Dataset Information

Maternal PUFA status but not prenatal methylmercury exposure is associated with children's language functions at age five years in the Seychelles.

Publications

Maternal PUFA status but not prenatal methylmercury exposure is associated with children's language functions at age five years in the Seychelles.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets