Marie Vahter

• PhD
• Karolinska Institutet

Background: There are indications that fluoride exposure considered to be beneficial for dental health may not be safe from a neurodevelopmental perspective. Objectives: To assess the impact of prenatal and childhood fluoride exposure on cognitive abilities at 5 and 10 years of age. Methods: We studied 500 mother-child pairs from the MINIMat (...

Toxic metal contaminants present in food and water have widespread effects on health and disease. Chalcophiles, such as arsenic, cadmium, and mercury, show a high affinity to selenium and exposure to these metals could have a modulating effect on enzymes dependent on selenocysteine in their active sites. The aim of this study was to assess the infl...

Introduction: Elevated phosphate (P) in urine may reflect a high intake of inorganic P salts from food additives. Elevated P in plasma is linked to vascular dysfunction and calcification. Objective: To explore associations between P in urine as well as in plasma and questionnaire-estimated P intake, and incidence of cardiovascular disease (CVD)....

Studies have indicated that early-life exposure to toxic metals and fluoride affects the immune system, but evidence regarding their role in allergic disease development is scarce. We aimed to evaluate the relations of exposure to such compounds in 482 pregnant women and their infants (4 months of age) with food allergy and atopic eczema diagnosed...

Our previous studies have linked gestational methylmercury exposure, originating from seafood, to changes in maternal thyroid hormones and infant birth size in a Swedish birth cohort. Herein we aimed to determine associations between maternal thyroid hormones and infant birth size and elucidate if maternal hormones could mediate the relationship be...

Intake of fish and seafood during pregnancy may have certain beneficial effects on fetal development, but measurement of intake using questionnaires is unreliable. Here, we assessed several candidate biomarkers of seafood intake, including long-chain omega 3 fatty acids (n-3 LCPUFA), selenium, iodine, methylmercury, and different arsenic compounds,...

Background: Several metals act as endocrine disruptors, but there are few large longitudinal studies about associations with puberty onset. Objectives: We evaluated whether early life cadmium, lead, and arsenic exposure was associated with timing of menarche. Methods: In a mother-child cohort in rural Bangladesh (n=935), the exposure was asses...

Background Observational studies have indicated that elevated maternal fluoride exposure during pregnancy may impair child neurodevelopment but a potential impact on birth outcomes is understudied. Objectives To evaluate the impact of gestational fluoride exposure on birth outcomes (birth size and gestational age at birth) and to assess the potent...

Background Severe iodine deficiency adversely affects neurodevelopment; however, evidence regarding the association of non-severe deficiency and child cognitive functioning is inconclusive. Methods This prospective mother-child cohort study was nested in a population-based nutritional supplementation trial in Bangladesh (Maternal and Infant Nutrit...

Background Cadmium (Cd) exposure during gestation has been associated with altered DNA methylation at birth, but it is not known if the changes in methylation persist into childhood. Objectives To evaluate whether gestational Cd-related changes of DNA methylation persist from birth to 9 years of age. Methods We studied mother–child dyads in a lon...

Humans living in the Andes Mountains have been historically exposed to arsenic from natural sources, including drinking water. Enzymatic methylation of arsenic allows it to be excreted more efficiently by the human body. Adaptation to high-arsenic environments via enhanced methylation and excretion of arsenic was first reported in indigenous women...

Background Iodine is essential for synthesizing thyroid hormones, but other micronutrients are also required for optimal thyroid function. However, there is a lack of data on combined micronutrient status in relation to thyroid hormones in pregnancy. Objective To assess the joint associations of iodine, selenium, and zinc status on plasma concentr...

Background Cadmium (Cd) is a toxic metal, which the non-smoking population is mainly exposed to through diet. Current health-based guidance values are based on renal toxicity; however, emerging evidence suggests that bone and the cardiovascular system might be more sensitive to Cd exposure. Objective To assess the association of urinary Cd (U-Cd)...

Background Food and water are common exposure sources of arsenic and lead among children. Whereas dietary sources of these toxicants are fairly well-studied, the contribution of drinking water to toxicant exposures is not well characterized in many populations, particularly in the Global South. Objective To assess the extent to which consumption o...

Iodine and selenium are essential trace elements. Recent studies indicate that pregnant and lactating women often have insufficient intake of iodine and selenium, but the impact on fetal and infant status is unclear. Here, we assessed iodine and selenium status of infants in relation to maternal intake and status of these trace elements in the birt...

Background Early-life exposure to arsenic (As), cadmium (Cd), and lead (Pb) has been linked to smaller birth and early childhood anthropometry, but little is known beyond the first years in life. Objectives To evaluate the impact of gestational and childhood exposures to As, Cd, and Pb on growth up to 10 years of age. Methods We studied 1530 moth...

Background: Several endocrine-disrupting metals may affect thyroid function, but the few available studies of exposure during pregnancy and thyroid hormones are inconclusive. Objective: To explore if environmental exposure to cadmium (Cd), lead (Pb), and methylmercury (MeHg) impacts thyroid function in pregnancy, and interacts with iodine and se...

Child growth depends on complex factors including diet, nutritional status, socioeconomic, and sanitary conditions, and exposure to environmental chemicals. Lead exposure is known to impair growth in young children but effects in school-age children are less clear. The effects of co-exposure to low-level lead and other toxic metals on child growth...

There is growing interest in understanding the contribution of environmental toxicant exposure in early life to development of cardiometabolic diseases (CMD) in adulthood. We aimed to assess associations of early life exposure to arsenic and cadmium with biomarkers of CMD in children in rural Bangladesh. From a longitudinal mother-child cohort in M...

Objective Arsenic is a known childhood neurotoxicant, but its neurotoxicity at low exposure levels is still not well established. The aim of our cross-sectional study was to test the association between low-level arsenic exposure and executive functions (EF) among children in Montevideo. We also assessed effect modification by arsenic methylation c...

Background: The uterine environment may be important for the chromosomal telomere length (TL) at birth, which, in turn, influences disease susceptibility throughout life. However, little is known about the importance of specific nutritional factors. Objectives: We assessed the impact of multiple maternal nutritional factors on TL in placenta and...

Background In the human body, inorganic arsenic (iAs) is methylated via the one-carbon cycle to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of iAs and MMA, and higher proportions of DMA in urine indicate efficient methylation; formation of DMA is thought to detoxify iAs and MMA. Studies on folate, vitamin B-1...

Background: Our studies of children in a rural Bangladeshi area, with varying concentrations of arsenic in well-water, indicated modest impact on child verbal cognitive function at 5 years of age. Objectives: Follow-up of arsenic exposure and children's cognitive abilities at school-age. Methods: In a nested sub-cohort of the MINIMat supplemen...

Observational studies have indicated that low-to-moderate exposure to cadmium (Cd), lead (Pb), and mercury (Hg) adversely affects birth anthropometry, but results are inconclusive. The aim of this study was to elucidate potential impact on birth anthropometry of exposure to Cd, Pb, and Hg in pregnant women, and to identify the main dietary sources....

Background: Detoxification of inorganic arsenic (iAs) occurs when it methylates to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of urinary iAs and MMA, and higher proportions of DMA indicate efficient methylation. The role of B-vitamins in iAs methylation in children with low-level arsenic exposure is underst...

Objectives: Millions of children globally, including the U.S., are exposed to low levels of arsenic from water and food. Arsenic is a known neurotoxicant at high levels but its effects at lower exposure levels are understudied. Arsenic methylation capacity, influenced by B-vitamin intake and status, potentially influences arsenic toxicity. In a cr...

There is limited knowledge of association between arsenic exposure and telomere length (TL) and signal joint T-cell receptor excision circle (sjTREC) that are potential biomarkers of immune senescence and disease susceptibility. We aimed to clarify whether long-term inorganic arsenic exposure influences TL and sjTRECs in childhood. Children born in...

Background The uterine environment may influence telomere length at birth, which is essential for cellular function, aging, and disease susceptibility over the lifespan. However, little is known about the impact of toxic chemicals on early-life telomeres. Therefore, we assessed the potential impact of multiple toxic metals on relative telomere leng...

Background: Experimental studies show developmental toxicity of boron and we recently found impaired weight and length in newborns of mothers exposed to boron through drinking water during pregnancy. Objectives: To evaluate potential impact of pre- and postnatal boron exposure on infant anthropometry. Methods: In our mother-child cohort (n = 1...

Background: Chronic cadmium exposure has been associated with osteotoxicity in adults, but little is known concerning its effects on early growth, which has been shown to be impaired by cadmium. Objectives: Our objective was to assess the impact of early-life cadmium exposure on bone-related biomarkers and anthropometry at 9 y of age. Methods:...

Background Biomarker selenium concentrations vary greatly between studies. Concentrations in erythrocytes, urine, and hair vary even at similar plasma concentrations, suggesting that unknown factors influence the distribution of selenium between body compartments. Objective To assess predictors of the different selenium biomarkers in children. De...

Elevated concentrations of inorganic arsenic, one of the most potent environmental toxicants and carcinogens, have been detected in well water around Lake Poopó Bolivia. This study aimed to assess human exposure to arsenic in villages around Lake Poopó and also to elucidate whether the metabolism and detoxification of arsenic in this population is...

Background: Cadmium (Cd) exposure has adverse health effects in children. Diet contributes to Cd exposure, but dietary components could affect body Cd levels. Objective: To examine associations between diet and urinary Cd (U-Cd) in children. Methods: In this cross-sectional study conducted in Montevideo, Uruguay, Cd exposure of 5-8 year old ch...

Children are concurrently exposed to low levels of multiple toxic metals but it is unclear how these exposures affect molecular processes like oxidative stress (OS), or the extent to which dietary components may reduce OS from these pro‐oxidants. In a cross‐sectional study of 6–8 y olds from Montevideo, Uruguay, we examined: 1) association of lead...

Introduction Prenatal and neonatal environmental factors, such as nutrition, microbes and toxicants, may affect health throughout life. Many diseases, such as allergy and impaired child development, may be programmed already in utero or during early infancy. Birth cohorts are important tools to study associations between early life exposure and dis...

Exposure to inorganic arsenic (As), a carcinogen and epigenetic toxicant, has been associated with lower circulating levels of insulin-like growth factor 1 (IGF1) and impaired growth in children of pre-school age. The aim of this study was to assess the potential impact of exposure to As on IGF1 and insulin-like growth factor-binding protein 3 (IGF...

Oxidative stress (OS) is an important consequence of exposure to toxic metals but it is unclear to what extent low-level metal exposures contribute to OS in children. We examined the cross-sectional association between urinary concentrations of arsenic (As), cadmium (Cd), and lead (Pb) and urinary markers of OS: F2-8α isoprostane and 8-hydroxy-2-de...

There is limited knowledge of association between arsenic exposure and telomere length (TL) and signal joint T-cell receptor excision circle (sjTREC) that are potential biomarkers of immune senescence and disease susceptibility. We aimed to clarify whether long-term inorganic arsenic exposure influences TL and sjTRECs in childhood. Children born in...

Boron is a naturally occurring metalloid, widely distributed in nature. Boron is not essential for humans. People are exposed to boron mainly via drinking water, including bottled water, and food, but also occupationally. Little is known about potential health effects of boron exposure. In experimental animal studies, boron exposure has been shown...

Background: Few studies have evaluated the association between low-level arsenic (As) exposure and cognitive performance among children. Objectives: In this cross-sectional study, we assessed the association between low-level As exposure and cognitive performance among 5-8 year-old children in Montevideo, and tested effect modification by As met...

Background: We have previously reported inverse associations of prenatal and childhood cadmium exposure with cognition in 5-year-old Bangladeshi children. Objectives: To assess if cadmium exposure affected cognition and behavior in the Bangladeshi children at 10 years. Methods: Cadmium exposure was assessed by urinary concentrations at 10 (n =...

Background: It has been proposed that interactions between selenium and arsenic in the body may affect their kinetics and toxicity. However, it is unknown how the elements influence each other in humans. Objectives: We aimed to investigate potential interactions in the methylation of selenium and arsenic. Methods: Urinary selenium (U-Se) and a...

Lead exposure remains an important public health problem. Contaminated foods may act as a source of lead exposure, while certain nutrients may reduce lead absorption. We examined the cross-sectional associations of dietary patterns and the intake of several nutrients and foods with blood (Pb-B) and urinary (Pb-U) lead concentrations in children (5-...

Background: In older adults, selenium status has been positively associated with cognitive function. We recently reported a positive association between maternal selenium status in pregnancy and children's cognitive function at 1.5 y. Objective: We followed up the children to assess if prenatal and childhood selenium status was associated with c...

Background: Hair is a commonly used exposure biomarker for metals and other trace elements, but concern has been raised regarding its appropriateness for assessing the internal dose. Objectives: The aim of the present study was to evaluate children's hair as biomarker of internal dose for toxic (As, Mn, Cd, Pb) and essential elements (Mg, Ca, Fe...

Background: Early-life arsenic exposure has been associated with reduced cell-mediated immunity, but little is known about its effects on humoral immunity. Objective: We evaluated whether prenatal and childhood arsenic exposure was associated with humoral immune function in school-aged children. Methods: Children born in a prospective mother–c...

Organisms have evolved the ability to tolerate toxic substances in their environments, often by producing metabolic enzymes that efficiently detoxify the toxicant. Inorganic arsenic is one of the most toxic and carcinogenic substances in the environment, but many organisms, including humans, metabolise inorganic arsenic to less toxic metabolites. T...

Analysis of AS3MT genomic sequences. (PDF)

Phylogenetic analysis of AS3MT proteins from animal, fungal, green and red algal, and other eukaryotic lineages, as well as bacterial and archaeal lineages, demonstrates the presence of AS3MT in different kingdoms. The tree with the highest log likelihood (-27427.9158) inferred from a maximum likelihood analysis using MEGA, as described in the Meth...

Phylogenetic analysis of the AS3MT central domain (defined in ref. [34]) shows similar clustering as for the whole AS3MT protein in Fig 2, main text. (PDF)

AS3MT gene and AS3MT protein sequences for selected species with data on arsenic methylation capacity. (PDF)

Sequence similarities between the human AS3MT protein in whole and methyltransferase domains only, and other species with data on arsenic methylation capacity. (PDF)

Phylogenetic analysis of AS3MT including only species in A) group I, and B) group II (as grouped in the AS3MT tree in Fig 2, main text) shows similar clustering of species within each group as within the tree containing both groups in Fig 2. AS3MT is widespread in different kingdoms, and in group I a close origin of AS3MT is found in animals, SAR (...

Alignment of AS3MT protein sequences for primates. The alignment contains species that can methylate arsenic: human (Homo sapiens) and rhesus monkey (Macaca mulatta), as well as two species that have been shown not to methylate arsenic (marked in red text), namely chimpanzee (Pan troglodytes, three isoforms) and marmoset monkey (Callithrix jacchus)...

Inventory of AS3MT homologs in organisms that can methylate arsenic. (PDF)

Phylogenetic analysis of the AS3MT N-terminal domain (defined in ref. [34]) shows similar clustering as for the whole AS3MT protein in Fig 2, main text. (PDF)

Phylogenetic analysis of the calcium transporter SERCA2 for the same species as those evaluated for AS3MT in Fig 2 (main text). SERCA2 is widespread in different kingdoms, but is absent in archaea. The tree with the highest log likelihood (-45266.0271), inferred from a maximum likelihood analysis as described in Experimental Procedures, is shown. T...

Phylogenetic analysis of the copper transporter ATP7A for the same species as those evaluated for AS3MT in Fig 2 (main text). ATP7A is widespread in different kingdoms. The tree with the highest log likelihood (-73039.0893), inferred from a maximum likelihood analysis as described in Experimental Procedures, is shown. The tree is drawn to scale, wi...

Species subjected to phylogenetic analysis and gene accession numbers. (PDF)

Analysis of constrained versus unconstrained trees by RAxML followed by a Kishino-Hasegawa test. In constrained trees, fungi and animal proteins were forced to cluster monophyletically. Statistics of constrained and unconstrained trees were subsequently scored. (PDF)

Background: Exposure to inorganic arsenic increases the risk of cancer and non-malignant diseases. Inefficient arsenic metabolism is a marker for susceptibility to arsenic toxicity. Arsenic may alter gene expression, possibly by altering DNA methylation. Objectives: To elucidate the associations between arsenic exposure, gene expression, and DNA...

Exposure to arsenic has been associated with increased risk of reduced lung function in adults, but the adverse impacts in early life are unclear. We aim to examine whether prenatal and childhood arsenic exposure is associated with reduced lung function and increased airway inflammation in school-aged children. Children born in the MINIMat cohort i...

Background: Methylmercury (MeHg) is a known developmental neurotoxicant present in fish, yet the impact of childhood exposure is uncertain, especially in children with poor nutrition. Objectives: To evaluate associations of MeHg exposure with cognitive abilities and behavior in children from a poor rural area in Bangladesh. Methods: The MeHg e...

The evidence regarding a potential link of low-to-moderate iodine deficiency, selenium status, and cadmium exposure during pregnancy with neurodevelopment is either contradicting or limited. We aimed to assess the prenatal impact of cadmium, selenium, and iodine on children’s neurodevelopment at 4 years of age. The study included 575 mother–child p...

Background: Exposure to lead, a common environmental pollutant, is known to cause cardiovascular and nephrotoxic effects in adults. Potential effects of early-life lead exposure on these functions are, however, less well characterized. Objectives: To assess blood pressure and kidney function in preschool-aged children in relation to prenatal lea...

Background: Exposure to inorganic arsenic (iAs) through drinking water causes cancer. Alterations in mitochondrial DNA copy number (mtDNAcn) and telomere length in blood have been associated with cancer risk. We elucidated if arsenic exposure alters mtDNAcn and telomere length in individuals with different arsenic metabolizing capacity. Methods: We...

Arsenic, an established carcinogen and toxicant, occurs in drinking water and food and affects millions of people worldwide. Arsenic appears to interfere with gene expression through epigenetic processes, such as DNA methylation and post-translational histone modifications. We investigated the effects of arsenic on histone residues in vivo as well...

Background: Boron is a metalloid found at highly varying concentrations in soil and water. Experimental data indicate that boron is a developmental toxicant, but the few human toxicity data available concern mostly male reproduction. Objectives: To evaluate potential effects of boron exposure through drinking water on pregnancy outcomes. Method...

Background: Cross-sectional studies have indicated impaired neurodevelopment with elevated drinking water manganese concentrations (W-Mn), but potential susceptible exposure windows are unknown. Objectives: We prospectively evaluated the effects of W-Mn, from fetal life to school age, on children's cognitive abilities and behavior. Methods: We...