Allergy and sensitization during childhood associated with prenatal and lactational exposure to marine pollutants

Association of allergies in children younger than 3 years with levels of maternal intake of n-3 polyunsaturated fatty acids or fish during pregnancy: A nationwide birth cohort study, the Japan Environment and Children's Study

BACKGROUND

N-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory properties and are expected to prevent the onset of allergies. However, epidemiological studies investigating the relationship between child allergies and maternal intake of n-3 PUFAs or fish have yielded inconsistent results.

METHODS

Following exclusions from a dataset comprising 103,057 records from the Japan Environment and Children's Study, 72,105 participants were divided into five groups according to mothers' intake of n-3 PUFAs or fish during pregnancy to assess the risk of their children being diagnosed with allergy by 3 years old. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for child allergies were calculated using multivariable logistic regression analyses with reference to the lowest intake group.

RESULTS

Levels of maternal intake of n-3 PUFAs or fish showed inverted associations (i.e., reduced risk) with the incidence of physician-diagnosed allergic rhinoconjunctivitis or parent-reported symptoms of current rhinitis with eye symptoms at different time points and the cumulative incidence from birth to 3 years of age. Inverted associations were also found for current wheeze at 1-<2 years of age and current eczema at 1-<2 and 0-<3 years of age. However, for food allergies, no significant associations were observed in the incidence in each group compared with the lowest intake group at any age.

CONCLUSIONS

The findings suggest that n-3 PUFA intake during pregnancy may reduce the risk of developing allergic diseases and symptoms in children. In addition, consumption of n-3 PUFAs or fish is very unlikely to increase the risk of allergy given that the results are from a country with high fish consumption.

TRIAL REGISTRATION

UMIN000030786 https://rctportal.niph.go.jp/detail/um?trial_id=UMIN000030786.

Infantile allergic diseases: a cohort study prenatal fish intake and mercury exposure context

BACKGROUND

Allergic diseases (ADs) have been increasingly reported in infants and children over the last decade. Diet, especially the inclusion of fish intake, may help to lower the risk of ADs. However, fish also, can bioaccumulate environmental contaminants such as mercury. Hence, our study aims to determine what effects the type and frequency of fish intake have on ADs in six-month-old infants, independently and jointly with mercury exposure.

METHODS

This study is part of the prospective birth cohort: Mothers and Children's Environmental Health (MOCEH) study in South Korea. Data was collected on prenatal fish intake, prenatal mercury concentration and ADs for infants aged six months for 590 eligible mother-infant pairs. Logistic regression analysis was conducted to evaluate the risk of prenatal fish intake and mercury concentration on ADs in infants. Finally, interaction between fish intake and mercury concentration affecting ADs in infants was evaluated. Hazard ratios of prenatal fish intake on ADs in 6 month old infants were calculated by prenatal mercury exposure.

RESULTS

Logistic regression analysis showed that white fish (OR: 0.53; 95% CI 0.30-0.94; P < 0.05) intake frequency, once a week significantly decreased the risk of ADs in infants. Stratification analysis showed that consuming white fish once a week significantly reduced the hazard of ADs (HR: 0.44; 95% CI 0.21-0.92; P < 0.05) in infants in the high-mercury (≥ 50th percentile) exposure group.

CONCLUSION

The result indicates that prenatal white fish intake at least once a week reduces the risk of ADs in infants, especially in the group with high prenatal mercury exposure.

Associations of exposure to metals with total and allergen-specific IgE: An NHANES analysis (2005-2006)

BACKGROUND

Immunoglobulin E (IgE) is a diagnostic biomarker for allergic diseases. While some metal exposure has been found to be associated with allergic diseases, there are still a lot of knowledge gaps regarding the relationship between metal exposure and allergen-specific IgE antibodies, particularly in adults.

METHODS

We included a total of 1433 adult participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES), all of whom had concentrations of 10 metals (including Barium (Ba), Cadmium (Cd), Cobalt (Co), Cesium (Cs), Molybdenum (Mo), Lead (Pb), Antimony (Sb), Thallium (Tl), Tungsten (Tu), and Uranium (Ur)) in urine, as well as measurements of 19 allergen-specific IgE and total IgE antibodies. Linear regression, logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to estimate associations between metals and total and allergen-specific IgE.

RESULTS

Linear regression models revealed a positive correlation between Pb and Cd levels and the total IgE levels. Furthermore, the WQS and BKMR models suggested a positive association between mixed metals and total IgE levels, with the WQS model highlighting Pb and Cd as the major contributors. Logistic regression models showed positive correlations between Pb and food sensitization, Ur and plant sensitization, negative correlations between Cs and plant sensitization, Co and dust mite and pet sensitization, Mo and dust mite and cockroach sensitization, and Tl and mold sensitization. Moreover, the BKMR results indicated a statistically significant negative correlation between mixed metals and mold sensitization.

CONCLUSION

According to the research findings, exposure to metals is associated with total and allergen-specific IgE in American adults. Further assessment of these relationships is necessary in representative populations of other countries.

Epidemiological evidence for the effect of environmental heavy metal exposure on the immune system in children

Heavy metals exist widely in daily life, and exposure to heavy metals caused by environmental pollution has become a serious public health problem worldwide. Due to children's age-specific behavioral characteristics and imperfect physical function, the adverse health effects of heavy metals on children are much higher than in adults. Studies have found that heavy metal exposure is associated with low immune function in children. Although there are reviews describing the evidence for the adverse effects of heavy metal exposure on the immune system in children, the summary of evidence from epidemiological studies involving the level of immune molecules is not comprehensive. Therefore, this review summarizes the current epidemiological study on the effect of heavy metal exposure on childhood immune function from multiple perspectives, emphasizing its risks to the health of children's immune systems. It focuses on the effects of six heavy metals (lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), nickel (Ni), and manganese (Mn)) on children's innate immune cells, lymphocytes and their subpopulations, cytokines, total and specific immunoglobulins, and explores the immunotoxicological effects of heavy metals. The review finds that exposure to heavy metals, particularly Pb, Cd, As, and Hg, not only reduced lymphocyte numbers and suppressed adaptive immune responses in children, but also altered the innate immune response to impair the body's ability to fight pathogens. Epidemiological evidence suggests that heavy metal exposure alters cytokine levels and is associated with the development of inflammatory responses in children. Pb, As, and Hg exposure was associated with vaccination failure and decreased antibody titers, and increased risk of immune-related diseases in children by altering specific immunoglobulin levels. Cd, Ni and Mn showed activation effects on the immune response to childhood vaccination. Exposure age, sex, nutritional status, and co-exposure may influence the effects of heavy metals on immune function in children.

Exposure to Heavy Metals and Allergic Outcomes in Children: a Systematic Review and Meta-analysis

It has been reported that heavy metals have adverse effects on the immune system. However, the relationship between heavy metal exposure and allergic outcomes remains unclear. This systematic review was conducted to examine whether heavy metal exposure is associated with allergic outcomes during childhood. We performed a systematic search of all relevant articles in Web of Science, EMBASE, and PubMed, from inception through to November 2020. We used odds ratio (OR) and the standard mean differences (SMDs) with 95% confidence intervals (CIs) to present estimates from individual studies. In addition, random-effects meta-analysis was used to pool the data. We also conducted the meta-regression and subgroup analysis to explore potential sources of heterogeneity. After duplicate removal, we finally included 35 articles in the systematic review and meta-analysis from an initial 11,181 articles. The overall results showed that copper (Cu) was associated with asthma (pooled SMD = 1.50, 95% CI = 0.13-2.86); in the subgroup analysis, the results indicated that lead (Pb) was associated with asthma (pooled OR = 6.27, 95% CI = 2.24-17.56), and Cu and Pb were connected with atopic dermatitis (SMD =  - 1.05, 95% CI =  - 1.45 to - 0.65; SMD = 5.68, 95% CI = 5.05-6.32), respectively. Mercury (Hg) was associated with atopic dermatitis (pooled OR = 1.13, 95% CI = 1.04-1.22) and wheeze (OR = 1.20, 95% CI = 1.05-1.37). The meta-analysis results indicate that Cu might be connected with childhood asthma, but not with other allergic diseases; Hg and Pb may have no association with allergic diseases during childhood. Given some limits observed in the current studies, more prospective cohort studies are still needed to verify our findings. Review registration: PROSPERO CRD42020222167.

Breastfeeding, pregnancy, medicines, neurodevelopment, and population databases: the information desert

Background

The pharmacoepidemiology of the long-term benefits and harms of medicines in pregnancy and breastfeeding has received little attention. The impact of maternal medicines on children is increasingly recognised as a source of avoidable harm. The focus of attention has expanded from congenital anomalies to include less visible, but equally important, outcomes, including cognition, neurodevelopmental disorders, educational performance, and childhood ill-health. Breastfeeding, whether as a source of medicine exposure, a mitigator of adverse effects or as an outcome, has been all but ignored in pharmacoepidemiology and pharmacovigilance: a significant ‘blind spot’.

Whole-population data on breastfeeding: why we need them

Optimal child development and maternal health necessitate breastfeeding, yet little information exists to guide families regarding the safety of medicine use during lactation. Breastfeeding initiation or success may be altered by medicine use, and breastfeeding may obscure the true relationship between medicine exposure during pregnancy and developmental outcomes. Absent or poorly standardised recording of breastfeeding in most population databases hampers analysis and understanding of the complex relationships between medicine, pregnancy, breastfeeding and infant and maternal health. The purpose of this paper is to present the arguments for breastfeeding to be included alongside medicine use and neurodevelopmental outcomes in whole-population database investigations of the harms and benefits of medicines during pregnancy, the puerperium and postnatal period. We review: 1) the current situation, 2) how these complexities might be accommodated in pharmacoepidemiological models, using antidepressants and antiepileptics as examples; 3) the challenges in obtaining comprehensive data.

Conclusions

The scarcity of whole-population data and the complexities of the inter-relationships between breastfeeding, medicines, co-exposures and infant outcomes are significant barriers to full characterisation of the benefits and harms of medicines during pregnancy and breastfeeding. This makes it difficult to answer the questions: ‘is it safe to breastfeed whilst taking this medicine’, and ‘will this medicine interfere with breastfeeding and/ or infants’ development’?

Maternal Exposure to Polychlorinated Biphenyls and Asthma, Allergic Rhinitis and Atopic Dermatitis in the Offspring: The Environmental Health Fund Birth Cohort

Background: Polychlorinated biphenyls (PCBs) are persistent organic pollutants banned for use worldwide. Due to their biodegradation resistance, they accumulate along the food chain and in the environment. Maternal exposure to PCBs may affect the fetus and the infant. PCBs are immunotoxic and may damage the developing immune system. PCBs are associated with elevated IgE antibodies in cord blood and are considered to be predictive of atopic reactions. Several studies on the association between prenatal exposure to PCBs and atopic reactions were previously published, albeit with conflicting results.

Objectives: To examine the association between maternal PCBs levels and atopic reactions in their offspring.

Methods: During the years 2013–2015, a prospective birth cohort was recruited at the delivery rooms of Shamir Medical Center (Assaf Harofeh) and “Dana Dwek” Children’s Hospital. Four PCBs congeners were investigated: PCBs 118, 138, 153, and 180. In 2019, when children reached the age of 4–6 years, mothers were interviewed using the ISAAC questionnaire to assess symptoms of atopic reactions, including asthma, allergic rhinitis, and atopic dermatitis.

Results: One hundred and fifty mother-child dyads were analyzed. No significant differences were found in the median serum PCBs concentrations of each studied congener or total PCBs for asthma, allergic rhinitis, atopic dermatitis diagnosis, or parent-reported symptoms. No association was found between exposure to total PCBs and the risk for asthma symptoms or diagnosis, adjusted to maternal age and family member with atopic condition: aOR = 0.94, 95%CI: (0.88; 0.99). No association was observed between each studied PCB congener and asthma symptoms or diagnosis. The same results were found also for other studied outcomes—allergic rhinitis and atopic dermatitis.

Conclusion: Our study joins a series of previous studies that attempt to shed light on environmental exposures in utero as influencing factors for atopic conditions in children. Our results reflect the complexity of the pathophysiology of these phenomena. No relationship between maternal serum PCBs levels was demonstrated for asthma, allergic rhinitis, or atopic dermatitis. However, additional multi-participant studies, with longer, spanning into later pediatric age follow up are needed.

Association between exposure to chemical mixtures in relation to serum total IgE among adults 19-86 years old

There is a scarcity of studies on the effects of mixed chemicals on total IgE. We aim to assess whether there is a link between chemical mixtures (blood and urine of 26 chemicals including lead, mercury, cadmium, t,t-muconic acid, benzylmercapturic acid , 1-hydroxypyrene, 2-naphthol, 2-hydroxyfluorene, 1-hydroxyphenanthrene, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-n-butyl phthalate, mono-benzyl phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, mono-carboxyoctyl phthalate, mono-carboxy-isononly phthalate, mono (3-carboxypropyl) phthalate, bisphenol A, bisphenol F, bisphenol S, triclosan, methylparaben, ethylparaben, propylparaben, 3-phenoxybenzoic acid, and cotinine), and total IgE in 3,642 Korean adults aged ≥ 19. The effects of mixed chemical exposure on total IgE were identified using linear regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The most relevant factors linked with IgE, according to the linear regression models, were blood or urine mercury and urine bisphenol A levels, with significant trends detected for these chemical tertiles (p < 0.01). The WQS index was significantly linked with ln2-transformed levels of serum total IgE (β = 0.30, 95 %CI 0.25-0.32). The qgcomp index also found a significant link between chemicals and ln2-transformed levels of serum total IgE (β = 0.52, 95 %CI 0.21-0.82), and elevated serum total IgE levels (OR = 2.55, 95 %CI 1.14-5.71). In BKMR analysis, the overall effect of the mixture was significantly associated with ln2-transformed levels of serum total IgE. The cutoff levels for exposure levels related to serum total IgE levels/elevated serum total IgE levels were reported. We discovered that whole-body exposure to 26 chemicals was associated with serum total IgE levels after assessing the findings of these four models. More research is needed in the future to gain a better understanding of the impact of mixed chemical exposure on allergic disorders and how to minimize chemical exposure, especially for people under the age of 18.

Sex specific associations between in utero exposure to persistent organic pollutants and allergy-related outcomes in childhood: The Rhea Mother-Child Cohort (Crete, Greece)

Accumulating evidence suggests that in utero exposures can influence the development of the immune system. Few studies have investigated whether prenatal exposure to persistent organic pollutants (POPs) is associated with allergy-related phenotypes in childhood, nor explored sex differences. We examined the association between prenatal exposure to POPs and offspring allergic outcomes in early and mid-childhood. We included 682 mother-child pairs from the prospective birth cohort Rhea. We measured dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and 6 polychlorinated biphenyl (PCB) congeners in maternal first trimester serum. Parents completed the questionnaires adapted from the International Study on Asthma and Allergy in Childhood (ISAAC) for allergy-related phenotypes when their children were 4 and 6 years old. We used Poisson regression models to estimate Risk Ratios. Prenatal HCB was associated with increased risk for rhinoconjunctivitis at 6 years (RR (95% CI): 2.5; (1.3, 4.8) for a doubling in the exposure). Among girls, prenatal DDE was associated with increased risk for current wheeze, current asthma and current rhinoconjunctivitis at 4 years (RR (95%CI): 1.4 (0.8, 2.6), 1.6 (1.1, 2.4) and 1.8 (1.0, 3.3) and p-interaction = 0.035, 0.027 and 0.059, respectively), with increased risk for current rhinoconjunctivitis at 6 years (RR (95%CI): 1.7 (0.7, 3.8) and p-interaction = 0.028) and total PCBs were associated with increased risk for current eczema at 4 years (RR (95%CI): 2.1 (1.1, 4.2) and p-interaction = 0.028). In boys, prenatal DDE was associated with decreased risk for current wheeze and current asthma at 4 years. Our findings suggest that even low levels of exposure to POPs prenatally may affect the development of childhood allergy-related outcomes in a sex and age-specific manner.

Pre and postnatal exposure to mercury and respiratory health in preschool children from the Spanish INMA Birth Cohort Study

Effects of mercury on maturing immune system have been reported, however the association with respiratory and allergy problems during infancy remains unclear. The aim of this study is to evaluate the association between pre and postnatal mercury exposure and respiratory and allergy problems among preschool children and to examine the role of potential modifying factors. Study subjects were children participant in Spanish Childhood and Environment Project (INMA, 2003-2008). We measured total mercury levels in cord blood (n = 1868) and hair at 4 years of age (n = 1347). Respiratory outcomes (wheezing, severe wheezing, chestiness, persistent cough, eczema and otitis) were obtained by questionnaires administered to parents. Associations were investigated by logistic regression adjusted for socio-demographic and lifestyle-related variables in each cohort and subsequent meta-analysis. We tested effect modification by factors related to individual susceptibility, diet and co-exposure with other pollutants. The geometric mean of cord blood and hair total mercury was 8.20 μg/L and 0.97 μg/g, respectively. No statistically significant association between pre or postnatal mercury exposure and respiratory and allergy outcomes was found. Notwithstanding, lower maternal intake of fruits and vegetables increased the risk of some respiratory outcomes due to the prenatal exposure to mercury (p_int < 0.05). Moreover, an inverse association between prenatal mercury exposure and some respiratory outcomes was observed among children with higher maternal exposure to organocholorine compounds or smoking (p_int < 0.05). Also, sex and postnatal smoking exposure modulated mercury postnatal effects on persistent cough (p_int < 0.05). In conclusion, no association between pre and postnatal mercury exposure and respiratory and allergy problems among the whole population at study was found. However, diet and other toxicants could modulate this relation, especially during prenatal period. More research on this topic is warranted due to the limited evidence.

Prenatal heavy metal exposures and atopic dermatitis with gender difference in 6-month-old infants using multipollutant analysis

BACKGROUND

Prenatal exposure to heavy metals during critical developmental phases has been implicated in allergic phenotypes. However, few studies have been conducted on the gender-specific association of prenatal heavy metal exposure with atopic dermatitis (AD) in infants.

OBJECTIVE

To examine the gender-specific association of prenatal exposure to multiple heavy metals with AD incidence in 6-month-old infants using data from the Mothers and Children's Environmental Health (MOCEH).

METHODS

We evaluated 738 mother-child pairs from the MOCEH study, an ongoing prospective birth cohort. The concentrations of three heavy metals (lead, mercury and cadmium) in maternal blood samples were measured during early and late pregnancy. Each quartile of heavy metal concentration was used to consider the possible nonlinear association with AD. For assessing the multi-pollutant model, we constructed the multivariate regression model including all three heavy metals at both early and late pregnancy. Further, the group Lasso model was used to perform the variable selection with categorized exposures and assess the effect of multiple pollutants including their pairwise interactions.

RESULTS

A total of 200 incident cases of AD were diagnosed in 6-month-old infants. In the multivariate regression model of the boy group, adjusted odds ratios comparing the second, third and fourth quartile of lead exposure in boys with the first quartile were 1.83 (95% CI: 1.00, 3.38), 1.04 (0.91, 3.32) and 2.40 (1.18, 4.90), respectively. However, the only second quartile of lead exposure compared to first quartile was significantly associated with AD in girls. In addition, the results of the group Lasso model were similar with the results of multivariate regression model.

CONCLUSION

The results suggest that lead exposure in late pregnancy increases risk of AD in 6-month-old boys although the strength of association is weak. Further studies are needed to confirm the susceptibility window and gender differences in lead-induced AD.

A systematic review of asthma case definitions in 67 birth cohort studies

BACKGROUND

Birth cohort studies are a valuable source of information about potential risk factors for childhood asthma. To better understand similarities and variations in findings between birth cohort studies, the methodologies used to measure asthma require consideration.

OBJECTIVE

To review and appraise the definitions of "asthma" used in birth cohort studies.

METHODS

A literature search, conducted in December 2017 in the MEDLINE database and birth cohort repositories, identified 1721 citations published since 1990. Information extracted included: study name, year of publication, sample size, sample age, prevalence of asthma (%), study region, source of information about asthma, measured outcome, and asthma case definition. A meta-analysis evaluated whether asthma prevalence in cohorts from Europe and North America varied by the studies' definition of asthma and by their data sources.

RESULTS

The final review included 67 birth cohorts, of which 48 (72%) were from Europe, 14 (21%) from North America, 3 (5%) from Oceania, 1 (1%) from Asia and 1 (1%) from South America. We identified three measured outcomes: "asthma ever", "current asthma", and "asthma" without further specification. Definitions of "asthma ever" were primarily based upon an affirmative parental response to the question whether the child had ever been diagnosed with asthma by a physician. The most frequently used definition of "current asthma" was "asthma ever" and either asthma symptoms or asthma medications in the last 12 months. This definition of "current asthma" was used in 16 cohorts. There was no statistically significant difference in the pooled asthma prevalence in European and North American cohorts that used questionnaire alone versus other data sources to classify asthma.

CONCLUSION

There is substantial heterogeneity in childhood asthma definitions in birth cohort studies. Standardisation of asthma case definitions will improve the comparability and utility of future cohort studies and enable meta-analyses.

The Association Between Mercury Exposure and Atopic Dermatitis in Early Childhood: A Mothers and Children's Environmental Health Study

BACKGROUND

Atopic dermatitis is a chronic and relapsing inflammatory skin disease. Although mercury has been suggested as a risk factor, the underlying mechanism and the relationship between mercury and atopic dermatitis remains unclear. The objective of the present study was to investigate the relationship between mercury exposure and the presence of atopic dermatitis in early childhood.

METHODS

This study is part of the prospective Mothers and Children's Environmental Health cohort study. A total of 1,751 pregnant women were enrolled in Mothers and Children's Environmental Health. After delivery, children were followed up. Blood samples were collected and mothers were asked about the presence of atopic dermatitis in their children via a questionnaire at 6, 12, 24, 36, and 60 months of age.

RESULTS

After excluding participants who did not meet the inclusion criteria, a total of 1,061 mother-children pairs were included in the analysis. The geometric mean of mercury concentrations in cord blood was 5.1 µg/L. In adjusted models, cord blood mercury exposure (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 1.0, 1.2 at 12-24 months) and postnatal mercury exposure (OR = 1.2; 95% CI = 1.0, 1.5 at 24-36 months, OR = 1.4; 95% CI = 1.1, 1.8 at 48-60 months) were associated with the presence of atopic dermatitis in children.

CONCLUSIONS

Postnatal mercury exposure at 24 months of age increases the risk of atopic dermatitis in children.

The aryl hydrocarbon receptor as a target of environmental stressors - Implications for pollution mediated stress and inflammatory responses

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor regulating the expression of genes, for instance encoding the monooxygenases cytochrome P450 (CYP) 1A1 and CYP1A2, which are important enzymes in metabolism of xenobiotics. The AHR is activated upon binding of polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), and related ubiquitous environmental chemicals, to mediate their biological and toxic effects. In addition, several endogenous and natural compounds can bind to AHR, thereby modulating a variety of physiological processes. In recent years, ambient particulate matter (PM) associated with traffic related air pollution (TRAP) has been found to contain significant amounts of PAHs. PM containing PAHs are of increasing concern as a class of agonists, which can activate the AHR. Several reports show that PM and AHR-mediated induction of CYP1A1 results in excessive generation of reactive oxygen species (ROS), causing oxidative stress. Furthermore, exposure to PM and PAHs induce inflammatory responses and may lead to chronic inflammatory diseases, including asthma, cardiovascular diseases, and increased cancer risk. In this review, we summarize findings showing the critical role that the AHR plays in mediating effects of environmental pollutants and stressors, which pose a risk of impacting the environment and human health.

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PAHs present on ambient air pollution particles are ligands of the cellular AHR.

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AHR-dependent induction of CYP1, AKR, NOX and COX-2 genes can be a source of ROS generation.

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AHR signaling and NRF2 signaling interact to regulate the expression of antioxidant genes.

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Air pollution and ROS can affect inflammation, which is partially triggered by AHR and associated immune responses.

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Skin, lung, and the cardiovascular system are major target sites for air pollution-induced inflammation.

Associations Between Metal Levels in Whole Blood and IgE Concentrations in Pregnant Women Based on Data From the Japan Environment and Children's Study

Background

Metal exposures could possibly affect allergic responses in pregnant women, although no studies have yet shown a clear relationship between the two, and such exposures might also affect the development of allergic diseases in children.

Methods

We investigated the relationship between metal concentrations in whole blood and immunoglobulin E (IgE; total and specific) in 14,408 pregnant women who participated in the Japan Environment and Children’s Study. The subjects submitted self-administered questionnaires, and blood samples were collected from them twice, specifically, during the first trimester and again during the second/third trimester. Concentrations of the metals Cd, Pb, Hg, Se, and Mn, as well as serum total and allergen-specific IgEs for egg white, house dust-mites (HDM), Japanese cedar pollen (JCP), animal dander, and moth, were measured. Allergen-specific IgE(s) were divided based on concentrations <0.35 or ≥0.35 UA/mL, and the metal levels were divided into quartiles.

Results

Multivariable logistic regression analysis showed that there was a significant negative correlation between HDM- and animal dander-specific IgEs and Hg and Mn concentrations. Conversely, there was a significant positive relationship between JCP-specific IgE and Hg and Se concentrations.

Conclusions

Metal exposures may be related to both increases and decreases in allergen-specific IgEs in pregnant women.

Fish, Shellfish, and Children's Health: An Assessment of Benefits, Risks, and Sustainability

American children eat relatively little fish and shellfish in comparison with other sources of animal protein, despite the health benefits that eating fish and shellfish may confer. At the same time, fish and shellfish may be sources of toxicants. This report serves to inform pediatricians about available research that elucidates health risks and benefits associated with fish and shellfish consumption in childhood as well as the sustainability of fish and shellfish harvests.

[Investigation of the Effects of Exposure to Chemical Substances on Child Health]

There is mounting concern about the effects of early-life exposure to chemical substances on children's health and development. We summarize the past and ongoing birth cohort studies carried out worldwide on the association between environmental exposure and children's health. Our PubMed search with the keywords 'birth cohort' revealed that the number of articles jumped from 200-300 in the 1980s to over 1,000 in the 1990s. Many of these articles reported elevated risks to children's health posed by chemical exposure owing their vulnerability. At the same time, policies implemented to reduce exposure to lead and dioxins were successful in the past few decades. Research also demonstrated that intervention to reduce exposure to certain chemicals whose exposure routes were well documented was also successful. We summarize the effects of early-life exposure to chemical substances on children's health and development. Our findings will hopefully help safeguard the environment in which future generations grow and live.

Prenatal exposure to mercury in relation to infant infections and respiratory symptoms in the New Hampshire Birth Cohort Study

BACKGROUND

Mechanistic studies support the potential for mercury (Hg) to alter immunity, including via in utero exposure. As yet, there are few prospective studies of in utero Hg exposure and subsequent immune-related outcomes, especially in infancy.

OBJECTIVES

We investigated the association of biomarkers of prenatal Hg exposure and maternal silver-mercury dental amalgams with the occurrence of infant allergy, respiratory infection, and respiratory symptoms in the first year of life.

METHODS

The New Hampshire Birth Cohort Study (NHBCS) ascertained information on infant allergies, infections and symptoms through telephone interviews at 4, 8 and 12 months postpartum and measured total Hg in maternal toenails collected at ~28-30 weeks gestation. Information on maternal fish consumption and presence of dental amalgams was obtained from a questionnaire administered at study enrollment at 24-28 weeks. A total of 1321 NHBCS mother-infant pairs had at least one Hg exposure measure (toenail Hg or information on dental amalgams) and information on dietary fish intake. Generalized linear models and generalized estimating equation models with Poisson regression adjusted for potential confounders (maternal age, level of education, parity, smoking, alternative Healthy Eating Index-2010, infant sex, gestational age, feeding mode, and day care attendance) were used to assess the association between infant outcomes and prenatal toenail Hg levels. We subsetted this analysis on mothers who consumed fish (n = 706) as a measure of in utero methylmercury (MeHg) exposure. Associations between infant outcomes and dental amalgams as a measure of in utero inorganic Hg exposure were assessed among mothers who did not consume fish (n = 218).

RESULTS

Among women who ate fish during pregnancy, higher maternal toenail Hg concentrations were associated with an increased risk of lower respiratory infections and respiratory symptoms requiring a doctor visit among infants age 9-12 months (relative risk (RR) 1.4 (95% CI: 1.1, 1.9) and 1.2 (95% CI: 1.0, 1.4) respectively), whereas a reduced risk of lower respiratory infections was observed among infants 0-4 months of age (RR = 0.7 (95% CI: 0.5, 1.0). We found little to no evidence of associations of toenail Hg with upper respiratory infections, allergy or eczema at any age to one year. Among infants of mothers who did not consume fish, we found an elevated risk of upper respiratory infections requiring a doctor visit in relation to having dental amalgams during pregnancy (RR = 1.5 (95% CI: 1.1, 2.1)). Overall, weaker associations were observed with lower respiratory infections, respiratory symptoms, and medically confirmed allergies, and there was no association with eczema.

CONCLUSIONS

Our analyses of a US birth cohort, along with prior mechanistic work, raise the possibility that gestational Hg exposure through fish/seafood consumption and dental amalgams may alter respiratory infections and respiratory symptoms in infants.

Infant milk-feeding practices and food allergies, allergic rhinitis, atopic dermatitis, and asthma throughout the life span: a systematic review

BACKGROUND

During the Pregnancy and Birth to 24 Months Project, the USDA and Department of Health and Human Services initiated a review of evidence on diet and health in these populations.

OBJECTIVES

The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding prior to infant formula introduction, 4) feeding a lower versus higher intensity of human milk to mixed-fed infants, and 5) feeding a higher intensity of human milk by bottle versus breast with food allergies, allergic rhinitis, atopic dermatitis, and asthma.

METHODS

The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published between January 1980 and March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence.

RESULTS

The systematic reviews numbered 1-5 above included 44, 35, 1, 0, and 0 articles, respectively. Moderate, mostly observational, evidence suggests that 1) never versus ever being fed human milk is associated with higher risk of childhood asthma, and 2) among children and adolescents who were fed human milk as infants, shorter versus longer durations of any human milk feeding are associated with higher risk of asthma. Limited evidence does not suggest associations between 1) never versus ever being fed human milk and atopic dermatitis in childhood or 2) the duration of any human milk feeding and allergic rhinitis and atopic dermatitis in childhood.

CONCLUSIONS

Moderate evidence suggests that feeding human milk for short durations or not at all is associated with higher childhood asthma risk. Evidence on food allergies, allergic rhinitis, and atopic dermatitis is limited.

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years

Perfluorinated alkylate substances (PFASs) are highly persistent and may cause immunotoxic effects. PFAS-associated attenuated antibody responses to childhood vaccines may be affected by PFAS exposures during infancy, where breastfeeding adds to PFAS exposures. Of 490 members of a Faroese birth cohort, 275 and 349 participated in clinical examinations and provided blood samples at ages 18 months and 5 years. PFAS concentrations were measured at birth and at the clinical examinations. Using information on duration of breastfeeding, serum-PFAS concentration profiles during infancy were estimated. As outcomes, serum concentrations of antibodies against tetanus and diphtheria vaccines were determined at age 5. Data from a previous cohort born eight years earlier were available for pooled analyses. Pre-natal exposure showed inverse associations with the antibody concentrations five years later, with decreases by up to about 20% for each two-fold higher exposure, while associations for serum concentrations at ages 18 months and 5 years were weaker. Modeling of serum-PFAS concentration showed levels for age 18 months that were similar to those measured. Concentrations estimated for ages 3 and 6 months showed the strongest inverse associations with antibody concentrations at age 5 years, particularly for tetanus. Joint analyses showed statistically significant decreases in tetanus antibody concentrations by 19-29% at age 5 for each doubling of the PFAS exposure in early infancy. These findings support the notion that the developing adaptive immune system is particularly vulnerable to immunotoxicity during infancy. This vulnerability appears to be the greatest during the first 6 months after birth, where PFAS exposures are affected by breast-feeding.

Brief Report: Low-level Mercury Exposure and Risk of Asthma in School-age Children

BACKGROUND

Although mercury exposure has been associated with several adverse health effects, the association with childhood asthma is under investigated. Therefore, we explore the association between mercury and childhood asthma in a population with low mercury levels.

METHODS

Mercury levels were measured in blood and urine in 1,056 children ages 5-14 years. In addition to including questions about asthma diagnosis and wheezing, the study measured bronchial hyperresponsiveness and allergic sensitization to common aeroallergens. Logistic regression analysis adjusted for major potential confounders.

RESULTS

Overall the adjusted odds ratios (aOR) between log blood mercury and the outcomes were 0.8 (95% CI: 0.63, 1.11) for asthma, 0.9 (95% CI: 0.79, 1.14) for wheeze, 1.1 (95% CI: 0.60, 2.03) for bronchial hyperresponsiveness, and 1.0 (95% CI: 0.80, 1.17) for allergic sensitization. Urine mercury adjusted for creatinine was also not associated with any of these allergy-related outcomes.

CONCLUSIONS

While the results did not support an association between mercury exposure and asthma, studies are needed to assess prenatal and lifetime exposure to mercury and asthma.

Prenatal exposure to polychlorinated biphenyls and asthma, eczema/hay fever, and frequent ear infections

OBJECTIVES

The effects of prenatal exposure to Polychlorinated biphenyls (PCBs) on the development of asthma, frequent ear infections, and eczema/hay fever are not well understood. We aim to investigate associations between prenatal PCB exposure and these health outcomes in the offspring of women who worked at the LaSalle Electrical Utilities Company (EUC).

METHODS

A retrospective cohort with at least one live birth and known employment time at EUC was eligible for this analysis. Exposure was defined and categorized by the number of fiscal quarters worked during the PCB era (1952-1981). A total of 288 women with 800 live births were included. A Chi-Square test was used to compare maternal and child characteristics across exposure groups and repeated measures logistic regression, controlling for clustering among siblings, was used to assess the associations between prenatal PCB exposure and these outcomes.

RESULTS

After adjustment for confounding and independent maternal predictors, 1-4 quarters of prenatal exposure to PCBs increased the odds for asthma (OR 3.24[1.30-8.09]), eczema/hay fever (OR 3.29[1.54-7.04]), and frequent ear infections (OR 2.24[1.19-4.22]) when compared with persons unexposed/exposed only to naphthalenes. The significance of the associations varied by exposure period and level of exposure, with the strongest associations in those employed exclusively after 1952 when PCBs were introduced.

CONCLUSIONS

These results support previous findings of associations of prenatal exposure to PCBs with asthma, eczema/hay fever, and frequent ear infections. Additional prospective studies are needed to confirm these findings. Also required are more precise PCB exposures to separate them from other exposures in occupational settings.

Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective data from three Faroese birth cohorts, with a total of 2,152 healthy mother–child dyads recruited between 1986 and 2009. The Faroe Islands is a subarctic fishing community, where pilot whale meat and blubber are part of the traditional marine diet. Exposures were measured in maternal hair, serum or umbilical cord blood. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. A doubling in ΣPCB, p,p’-DDE and mercury concentrations were associated with increased odds by 8% (95% CI = 0–16%), 7% (95% CI = 0–14%) and 9% (95% CI = 2–17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention.

The chemical disruption of human metabolism

BACKGROUND

Recent evidence highlights the reality of unprecedented human exposure to toxic chemical agents found throughout our environment - in our food and water supply, in the air we breathe, in the products we apply to our skin, in the medical and dental materials placed into our bodies, and even within the confines of the womb. With biomonitoring confirming the widespread bioaccumulation of myriad toxicants among population groups, expanding research continues to explore the pathobiological impact of these agents on human metabolism.

METHODS

This review was prepared by assessing available medical and scientific literature from Medline as well as by reviewing several books, toxicology journals, government publications, and conference proceedings. The format of a traditional integrated review was chosen.

RESULTS

Toxicant exposure and accrual has been linked to numerous biochemical and pathophysiological mechanisms of harm. Some toxicants effect metabolic disruption via multiple mechanisms.

CONCLUSIONS

As a primary causative determinant of chronic disease, toxicant exposures induce metabolic disruption in myriad ways, which consequently result in varied clinical manifestations, which are then categorized by health providers into innumerable diagnoses. Chemical disruption of human metabolism has become an etiological determinant of much illness throughout the lifecycle, from neurodevelopmental abnormalities in-utero to dementia in the elderly.

Atopic Eczema: Genetic Associations and Potential Links to Developmental Exposures

Atopic eczema (AE), or atopic dermatitis (AD), is a common inflammatory skin disease with a disrupted epidermal barrier and an allergic immune response. AD/AE is prominently characterized by a symptomatic itch and transient skin lesions. Infants compose a significant percentage affected. Two models have been proposed to explain AD/AE skin pathology: the gut microbiome-focused inside-outside model and the outside-inside model concentrating on the disrupted skin barrier/skin microbiome. Gene disruptions contributing to epidermal structure, as well as those in immune system genes, are implicated. Over 30 genes have been linked to AD/AE with Flg and Tmem79/Matt alterations being common. Other linked disruptions are in the interleukin-1 family of cytokines/receptors and the TH2 gene family of cytokines. Inheritable epigenetic modifications of the genes or associated proteins may also be involved. Skin barrier disruption and the allergic immune response have been the main foci in mechanistic studies of AD/AE, but the role of the environment is becoming more apparent. Thus, an examination of in utero exposures could be very helpful in understanding the heterogeneity of AD/AE. Although research is limited, there is evidence that developmental exposure to environmental tobacco smoke or phthalates may impact disease. Management for AD/AE includes topical corticosteroids and calcineurin inhibitors, which safely facilitate improvements in select individuals. Disease heterogeneity warrants continued research not only into elucidating disease mechanism(s), via identification of contributing genetic alterations, but also research to understand how/when these genetic alterations occur. This may lead to the cure that those affected by AD/AE eagerly await.

Fish intake during pregnancy or infancy and allergic outcomes in children: A systematic review and meta-analysis

It has been suggested that n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) have anti-inflammatory properties and may reduce the risk of allergic disease. Fish is a great source of n-3 LC-PUFAs. However, the effect of fish on allergic disease remains controversial. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) and prospective cohort studies regarding the effect of fish intake during pregnancy or infancy on allergic outcomes in children. The outcomes of interest were atopy, eczema, allergic rhinitis, wheeze, asthma, and food allergy. One RCT and 17 publications from 13 prospective cohort studies were included for maternal fish intake during pregnancy, and eight publications from five prospective cohort studies for fish intake in infancy. Pooled analysis suggested that maternal fish intake during pregnancy was not associated with lower risk of any allergic outcome, both in RCT and observational studies. Consumption of fish during the first year of life reduced the risk of eczema (RR 0.61; 95% CI 0.47, 0.80; p = 0.0003; I²  = 68%) and allergic rhinitis (RR 0.54; 95% CI 0.36, 0.81; p = 0.003; I²  = 74%). Current evidence indicates that fish intake in infancy could reduce the risk of eczema and allergic rhinitis in children, whereas maternal fish intake during pregnancy does not affect any atopic outcome. The intake of fish per se in infancy, not specially n-3 LC-PUFAs, may have an allergy protective effect. High-quality and adequately powered RCTs are warranted to confirm this.

Association between perfluoroalkyl substance exposure and asthma and allergic disease in children as modified by MMR vaccination

Perfluoroalkyl substances (PFASs) are highly persistent chemicals that might be associated with asthma and allergy, but the associations remain unclear. Therefore, this study examined whether pre- and postnatal PFAS exposure was associated with childhood asthma and allergy. Measles, mumps, and rubella (MMR) vaccination in early life may have a protective effect against asthma and allergy, and MMR vaccination is therefore taken into account when evaluating these associations. In a cohort of Faroese children whose mothers were recruited during pregnancy, serum concentrations of five PFASs - Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) - were measured at three timepoints (maternal serum in pregnancy week 34-36 and child serum at ages 5 and 13 years) and their association with immunoglobulin E (IgE) (cord blood and at age 7 years) and asthma/allergic diseases (questionnaires at ages 5 and 13 years and skin prick test at age 13 years) was determined. A total of 559 children were included in the analyses. Interactions with MMR vaccination were evaluated. Among 22 MMR-unvaccinated children, higher levels of the five PFASs at age 5 years were associated with increased odds of asthma at ages 5 and 13. The associations were reversed among MMR-vaccinated children. Prenatal PFAS exposure was not associated with childhood asthma or allergic diseases regardless of MMR vaccination status. In conclusion, PFAS exposure at age 5 was associated with increased risk of asthma among a small subgroup of MMR-unvaccinated children but not among MMR-vaccinated children. While PFAS exposure may impact immune system functions, this study suggests that MMR vaccination might be a potential effect-modifier.

Does Breast-feeding Relate to Development of Atopic Dermatitis in Young Korean Children?: Based on the Fourth and Fifth Korea National Health and Nutrition Examination Survey 2007-2012

Purpose

There have been conflicting reports concerning the relationship between breast-feeding and the development of atopic dermatitis (AD) in early childhood. The objective of this study was to investigate the associations between breast-feeding and the risk of AD in early childhood in Korea.

Methods

We combined the fourth and fifth Korea National Health and Nutrition Examination Survey data collected from 2007 to 2012 and analyzed 2,015 children at 1 to 3 years old. Regression analysis was used to determine the association of the following variables: AD, feeding types, duration of breast-feeding, and others.

Results

The annual prevalence of exclusive breast-feeding and AD decreased. Parents with allergic diseases preferred breast-feeding and extended duration of feeding compared with those without. In multiple logistic regression analyses, exclusive breast-feeding in feeding type I (P=0.070; adjusted odds ratio [OR]=1.990), exclusive breast-feeding in feeding type II (P=0.095; adjusted OR=1.495) and breast-feeding duration (P=0.430; adjusted OR=1.013) were not significantly related to AD.

Conclusions

Breast-feeding was not found to be associated with an occurrence of AD in young children. Rather, parents with histories of allergic diseases tended to prefer breast-feeding and extend its duration. To clarify the role of breast-feeding in the development of AD, a nation-wide prospective study is needed.

Prenatal exposure to persistent organic pollutants and offspring allergic sensitization and lung function at 20 years of age

BACKGROUND

Prenatal exposures to persistent organic pollutants (POPs) have been associated with asthma medication use and self-reported symptoms, but associations with lung function and allergic sensitization have been minimally explored. The aim of the study was to examine the associations between prenatal exposures to POPs and allergic sensitization and lung function in 20-year-old offspring.

METHODS

In a Danish cohort of 965 pregnant women established in 1988-1989, six polychlorinated biphenyl (PCB) congeners, hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p'-DDE) were quantified in archived maternal serum drawn in gestational week 30 (n = 872). Among those with available maternal exposure information, at age 20, 421 offspring attended attended a clinical examination including measurements of allergic sensitization (serum-specific IgE ≥ 0.35 kUA /L) (n = 418) and lung function [forced expiratory volume in one second (FEV1 ) and forced vital capacity (FVC)] (n = 414).

RESULTS

There were no associations between maternal concentrations of POPs and offspring allergic sensitization at 20 years of age. Maternal concentrations of POPs were, however, positively associated with offspring airway obstruction (FEV1 /FVC < 75%). Compared to offspring in the first tertile of exposure, offspring in the third tertile of dioxin-like PCB exposure had an OR of 2.96 (95% CI: 1.14-7.70). Similar associations for non-dioxin-like PCBs, HCB, and p,p'-DDE were 2.68 (1.06-6.81), 2.63 (1.07, 6.46), and 2.87 (1.09, 7.57), respectively. No associations were observed with reduced lung function (FEV1 % of predicted value < 90%).

CONCLUSION AND CLINICAL RELEVANCE

Our data indicate that prenatal exposure to POPs appears to be associated with airway obstruction but not allergic sensitization at 20 years of age. The findings support that chronic obstructive lung diseases may have at least part of their origins in early life.

Air Pollution During Pregnancy and Cord Blood Immune System Biomarkers

OBJECTIVES

We aimed to determine whether average and trimester-specific exposures to ambient measures of nitrogen dioxide (NO2) and particular matter (PM2.5) were associated with elevated cord blood concentrations of immunoglobulin E (IgE) and two epithelial cell produced cytokines: interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP).

METHODS

This study utilized data and biospecimens from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. There were 2001 pregnant women recruited between 2008 and 2011 from 10 Canadian cities. Maternal exposure to NO2 and PM2.5 was estimated using land use regression and satellite-derived models.

RESULTS

We observed statistically significant associations between maternal NO2 exposure and elevated cord blood concentrations of both IL-33 and TSLP among girls but not boys.

CONCLUSIONS

Maternal NO2 exposure may impact the development of the newborn immune system as measured by cord blood concentrations of two cytokines.

Shorter duration of breastfeeding at elevated exposures to perfluoroalkyl substances

The aim of this study was to determine whether maternal exposure to persistent perfluoroalkyl substances (PFASs) affect the capability to breastfeed. In two Faroese birth cohorts (N=1130), concentrations of five PFASs were measured in maternal serum during pregnancy or two weeks after term. Duration of breastfeeding was assessed by questionnaire and clinical interview. In adjusted linear regression models, a doubling of maternal serum PFASs was associated with a reduction in duration of both total and exclusive breastfeeding, most pronounced for perfluorooctane sulfonic acid (PFOS) where a doubling was associated with a reduction in total breastfeeding of 1.4 (95% CI: 0.6; 2.1) months and perfluorooctanoic acid (PFOA) where a doubling was associated with a reduction in exclusive breastfeeding of 0.5 (0.3; 0.7) months. The associations were evident among both primiparous and multiparous women, and thus cannot be explained by confounding from previous breastfeeding.

Preconception Care: A New Standard of Care within Maternal Health Services

Emerging research suggests that much pediatric affliction has origins in the vulnerable phase of fetal development. Prenatal factors including deficiency of various nutrients and exposure to assorted toxicants are major etiological determinants of myriad obstetrical complications, pediatric chronic diseases, and perhaps some genetic mutations. With recent recognition that modifiable environmental determinants, rather than genetic predestination, are the etiological source of most chronic illness, modification of environmental factors prior to conception offers the possibility of precluding various mental and physical health conditions. Environmental and lifestyle modification through informed patient choice is possible but evidence confirms that, with little to no training in clinical nutrition, toxicology, or environmental exposures, most clinicians are ill-equipped to counsel patients about this important area. With the totality of available scientific evidence that now exists on the potential to modify disease-causing gestational determinants, failure to take necessary precautionary action may render members of the medical community collectively and individually culpable for preventable illness in children. We advocate for environmental health education of maternity health professionals and the widespread adoption and implementation of preconception care. This will necessitate the translation of emerging knowledge from recent research literature, to health professionals, to reproductive-aged women, and to society at large.

Maternal and Pediatric Health Outcomes in relation to Gestational Vitamin D Sufficiency

Juxtaposed with monumental improvement in maternal-fetal outcomes over the last century, there has been the recent emergence of rising rates of gestational complications including preterm birth, operative delivery, and gestational diabetes. At the same time, there has been a burgeoning problem with widespread vitamin D deficiency among populations of many developed nations. This paper provides a brief review of potential health outcomes recently linked to gestational vitamin D deficiency, including preterm birth, cesarean delivery, and gestational diabetes. Although immediate costs for obstetric complications related to gestational vitamin D insufficiency may be modest, the short- and long-term costs for pediatric healthcare resulting from such gestational complications may be enormous and present an enduring burden on healthcare systems. With increasing evidence pointing to fetal origins of some later life disease, securing vitamin D sufficiency in pregnancy appears to be a simple, safe, and cost-effective measure that can be incorporated into routine preconception and prenatal care in the offices of primary care clinicians. Education on gestational nutritional requirements should be a fundamental part of medical education and residency training, instruction that has been sorely lacking to date.

Asthma and allergy in children with and without prior measles, mumps, and rubella vaccination

BACKGROUND

The existing literature on the association between measles vaccination and subsequent risk of allergic disease is inconclusive. The aim of this study was, therefore, to determine whether measles, mumps, and rubella (MMR) vaccination administered in early childhood was associated with asthma and allergic diseases at ages 5, 7 and 13 yrs in a birth cohort.

METHODS

In the Faroe Islands, 640 children were followed from birth. Follow-up examinations at ages 5, 7 and 13 yrs included a physical examination and a maternal questionnaire about the child's health. At age 7, total and grass-specific IgE was quantified in the child's serum, and at age 13, the children underwent skin prick tests (SPT). The child's vaccination card was reviewed at examinations.

RESULTS

At age 5, 533 of 555 children had been vaccinated for MMR. After confounder adjustment, we found early life MMR vaccination to be associated with a two-third reduction in the odds of asthma (OR: 0.33, 95% CI: 0.12; 0.90) and hypersensitivity/allergy (OR: 0.32, 95% CI: 0.11; 0.88) at age 5, and the substantially decreased odds of asthma were replicated at age 13 (OR: 0.22, 95% CI: 0.08; 0.56). At age 7, serum total IgE was reduced by 62.8% (CI 95%: -84.3%; -11.9%) in the vaccinated children. MMR vaccination was not significantly associated with allergic rhinoconjuctivitis symptoms, eczema, or SPT reactions at age 13.

CONCLUSIONS

MMR vaccination early in life may have a protective effect against allergy at least up to age 7 and against asthma through age 13 yrs.

Maternal exposure to metals and persistent pollutants and cord blood immune system biomarkers

BACKGROUND

The fetal time period is a critical window of immune system development and resulting heightened susceptibility to the adverse effects of environmental exposures. Epidemiologists and toxicologists have hypothesized that persistent organic pollutants, pesticides and metals have immunotoxic properties. Immunotoxic effects may manifest as an altered immune system profile at birth. Immunoglobulin E, thymic stromal lymphopoietin (TSLP), and interleukin-33 (IL-33) may be implicated in the etiology of childhood allergy and are detectable at birth. The objective of this study was to examine the potential relationship between maternal concentrations of metals, persistent organic pollutants, and pesticides and elevated umbilical cord blood concentrations of IgE, TSLP, and IL-33 in a Canadian birth cohort.

METHODS

This study utilized data collected in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a trans-Canada cohort study of 2,001 pregnant women. Of these women, 1258 had a singleton, term birth and cord blood sample. Logistic regression was used to determine associations between log-transformed continuous variables and immune system biomarkers.

RESULTS

Inverse relationships were observed between lead, DDE, PCB-118, and a summary index of organophosphorous metabolites and jointly elevated concentrations of IL-33 and TSLP. None of the environmental contaminants were associated with increased odds of a high cord blood immune system biomarker concentration.

CONCLUSIONS

In this primarily urban Canadian population of pregnant women and their newborns, maternal blood or urine concentrations of persistent organic pollutants, pesticides, and metals were not associated with immunotoxic effects that manifest as increased odds of elevated concentrations of IgE, TSLP or IL-33.

Association of PCBs and allergies in children

Recently, the incidence rates of childhood allergies have been rising around the world. The presence of persistent chemical pollutants in the environment and exposure to air pollutants are often cited as potential causes of childhood allergies. Accordingly, epidemiological studies of the associations between exposure to low levels of pollutants and adverse health effects are essential. However, at present no useful biomarkers for evaluating such associations have been developed. Thus, using a molecular epidemiological approach we planned to identify candidate biomarkers of pollutant-induced adverse health effects that can be used in children. In asthmatic children, we found that the serum levels of several polychlorinated biphenyl (PCB) congener sub-types were significantly positively correlated with interleukin (IL)-8 mRNA expression, whereas in a sub-group of children who displayed positive immunoglobulin E (IgE) responses to milk or egg proteins IL-22 mRNA expression was demonstrated to be useful for detecting the adverse health effects of environmental pollutants, particularly PCB congeners. In conclusion, the mRNA expression levels of IL-8 and IL-22 can be used to detect children who are at particular risk of adverse health events caused by environmental pollutants, especially PCBs.

The Microbiome and Sustainable Healthcare

Increasing prevalences, morbidity, premature mortality and medical needs associated with non-communicable diseases and conditions (NCDs) have reached epidemic proportions and placed a major drain on healthcare systems and global economies. Added to this are the challenges presented by overuse of antibiotics and increased antibiotic resistance. Solutions are needed that can address the challenges of NCDs and increasing antibiotic resistance, maximize preventative measures, and balance healthcare needs with available services and economic realities. Microbiome management including microbiota seeding, feeding, and rebiosis appears likely to be a core component of a path toward sustainable healthcare. Recent findings indicate that: (1) humans are mostly microbial (in terms of numbers of cells and genes); (2) immune dysfunction and misregulated inflammation are pivotal in the majority of NCDs; (3) microbiome status affects early immune education and risk of NCDs, and (4) microbiome status affects the risk of certain infections. Management of the microbiome to reduce later-life health risk and/or to treat emerging NCDs, to spare antibiotic use and to reduce the risk of recurrent infections may provide a more effective healthcare strategy across the life course particularly when a personalized medicine approach is considered. This review will examine the potential for microbiome management to contribute to sustainable healthcare.

Monitoring chlorinated persistent organic pollutants in adolescents in Flanders (Belgium): concentrations, trends and dose-effect relationships (FLEHS II)

BACKGROUND

In 2007, the second cycle of the Flemish human biomonitoring survey started, with a main focus on 14-15 year-old adolescents.

OBJECTIVES

The main objectives were generating reference values for exposure markers, determining the pollution pressure in industrial hotspots and establishing dose-effect relationships between exposure to pollutants and hormone levels, sexual development, asthma and allergy, genotoxic and hematological markers.

METHODS

Geometric means with 95% confidence intervals (CI) were calculated for a reference population of 200 14-15 year-old adolescents. Stepwise multiple regression analyses with correction for confounders and covariates were performed to establish dose-effect relationships.

RESULTS

Geometric mean concentrations (with 95% CI) of 49.6 (45.7, 53.8), 70.8 (63.6, 78.8) and 8.34 (7.76, 8.97) n gg(-1) lipid for the sum of PCB 138, 153 and 180, p,p'-DDE and HCB were respectively 23%, 26% and 60% lower than those obtained five years earlier. Geometric mean concentrations of 108 (101, 114) and 32.1 (30.1, 34.2) pgCALUX-BEQg(-1) lipid were observed for the PCDD/Fs and dioxin-like PCBs, respectively. Multiple dose-effect relationships were observed between POPs and several effect markers, including positive (boys) and negative (girls) associations with data on sexual development and positive associations with asthma, animal allergy and free thyroxine (boys and girls).

CONCLUSIONS

Our findings suggest that chlorinated POP concentrations are decreasing over time and that even relatively low concentrations are associated with biological effects.

Autoantibodies associated with prenatal and childhood exposure to environmental chemicals in Faroese children

Methylmercury, polychlorinated biphenyls (PCBs), and perfluorinated compounds (PFCs) are ubiquitous and persistent environmental chemicals with known or suspected toxic effects on the nervous system and the immune system. Animal studies have shown that tissue damage can elicit production of autoantibodies. However, it is not known if autoantibodies similarly will be generated and detectable in humans following toxicant exposures. Therefore, we conducted a pilot study to investigate if autoantibodies specific for neural and non-neural antigens could be detected in children at age 7 years who have been exposed to environmental chemicals. Both prenatal and age-7 exposures to mercury, PCBs, and PFCs were measured in 38 children in the Faroe Islands who were exposed to widely different levels of these chemicals due to their seafood-based diet. Concentrations of IgM and IgG autoantibodies specific to both neural (neurofilaments, cholineacetyltransferase, astrocyte glial fibrillary acidic protein, and myelin basic protein) and non-neural (actin, desmin, and keratin) antigens were measured and the associations of these autoantibody concentrations with chemical exposures were assessed using linear regression. Age-7 blood-mercury concentrations were positively associated with titers of multiple neural- and non-neural-specific antibodies, mostly of the IgM isotype. Additionally, prenatal blood-mercury and -PCBs were negatively associated with anti-keratin IgG and prenatal PFOS was negatively associated with anti-actin IgG. These exploratory findings demonstrate that autoantibodies can be detected in the peripheral blood following exposure to environmental chemicals. The unexpected association of exposures with antibodies specific for non-neural antigens suggests that these chemicals may have toxicities that have not yet been recognized.

Does maternal diet during pregnancy and lactation affect outcomes in offspring? A systematic review of food-based approaches

OBJECTIVES

The aim of this study was to investigate the relationship between maternal diet during pregnancy and lactation and development of atopic disorders in childhood.

METHODS

We included studies published up to August 2011 that assessed food-based maternal dietary interventions or that examined associations between maternal dietary intake during pregnancy and/or lactation and allergic outcomes (eczema, asthma, hay fever, and sensitization) in their children.

RESULTS

We included 42 studies (>40 000 children): 11 intervention studies (including 7 randomized control trials), 26 prospective cohort studies, 4 retrospective cohort studies, and 1 case-control study. In the randomized control trials, no significant difference was noted overall in the prevalence of eczema and asthma in the offspring of women on diets free from common food allergens during pregnancy. The prospective cohorts investigated a large number of potential associations, but reported few significant associations between maternal dietary intake and development of allergy. Maternal diets rich in fruits and vegetables, fish, and foods containing vitamin D and Mediterranean dietary patterns were among the few consistent associations with lower risk for allergic disease in their children. Foods associated with higher risk included vegetable oils and margarine, nuts, and fast food.

CONCLUSION

This review did not find widespread or consistent links between mothers' dietary intake and atopic outcomes in their children. However, maternal consumption of Mediterranean dietary patterns, diets rich in fruits and vegetables, fish, and vitamin D-containing foods were suggestive of benefit, requiring further evaluation.

Potential risk of asthma associated with in utero exposure to xenobiotics

The incidence of asthma, a complex disease and significant public health problem, has been increasing over the last 30 years for unknown reasons. Changes in environmental exposures or lifestyle may be involved. In some cases asthma may originate in utero or in early life. Associations have been found between in utero exposures to several xenobiotics and increased risk of asthma. There is convincing evidence that maternal smoking and/or in utero and perinatal exposure to environmental tobacco smoke are associated with increased risk of asthma. Similar effects have been demonstrated in animal models of allergic asthma. Evidence also suggests that in utero and/or early-life exposures to various ambient air pollutants may increase the risk of asthma although supporting animal data are very limited. A few studies have suggested that in utero exposure to acetaminophen is associated with increased risk of asthma; however, animal data are lacking. Various vitamin deficiencies and supplements during pregnancy have been studied. In general, it appears that vitamins A, C, and E have protective effects and vitamins D and B may, in some instances, increase the risk, but the data are not conclusive. Some studies related to in utero exposures to polychlorinated biphenyls and bisphenol A and asthma risk are also reported. The underlying mechanisms for an association between xenobiotic exposures and asthma remain a matter of speculation. Genetic predisposition and epigenetic changes have been explored. The developing immune, respiratory, and nervous systems are potential targets. Oxidative stress and modulation of inflammation are thought to be involved.

Developmental Immunotoxicity, Perinatal Programming, and Noncommunicable Diseases: Focus on Human Studies

Developmental immunotoxicity (DIT) is a term given to encompass the environmentally induced disruption of normal immune development resulting in adverse outcomes. A myriad of chemical, physical, and psychological factors can all contribute to DIT. As a core component of the developmental origins of adult disease, DIT is interlinked with three important concepts surrounding health risks across a lifetime: (1) the Barker Hypothesis, which connects prenatal development to later-life diseases, (2) the hygiene hypothesis, which connects newborns and infants to risk of later-life diseases and, (3) fetal programming and epigenetic alterations, which may exert effects both in later life and across future generations. This review of DIT considers: (1) the history and context of DIT research, (2) the fundamental features of DIT, (3) the emerging role of DIT in risk of noncommunicable diseases (NCDs) and (4) the range of risk factors that have been investigated through human research. The emphasis on the human DIT-related literature is significant since most prior reviews of DIT have largely focused on animal research and considerations of specific categories of risk factors (e.g., heavy metals). Risk factors considered in this review include air pollution, aluminum, antibiotics, arsenic, bisphenol A, ethanol, lead (Pb), maternal smoking and environmental tobacco smoke, paracetamol (acetaminophen), pesticides, polychlorinated biphenyls, and polyfluorinated compounds.

Maternal concentrations of persistent organochlorine pollutants and the risk of asthma in offspring: results from a prospective cohort with 20 years of follow-up

BACKGROUND

Previous findings suggest that developmental exposures to persistent organochlorine pollutants (POPs) may be detrimental for the development of the immune system in the offspring. Whether these suspected immunoregulatory effects persist beyond early childhood remains unclear.

OBJECTIVES

The objective of this study was to evaluate the association between maternal serum concentrations of POPs and the risk of asthma in offspring after 20 years of follow-up.

METHODS

A birth cohort with 965 women was formed in 1988-1989 in Aarhus, Denmark. Concentrations of six polychlorinated biphenyls (PCBs) (congeners 118, 138, 153, 156, 170, 180), hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p´-DDE) were quantified in maternal serum (n=872) collected in gestation week 30. Information about offspring use of asthma medications was obtained from the Danish Registry of Medicinal Product Statistics.

RESULTS

Maternal serum concentrations of HCB and dioxin-like PCB-118 were positively associated with offspring asthma medication use after 20 years of follow-up (p for trend<0.05). Compared with subjects in the first tertile of maternal concentration, those in the third tertile of PCB-118 had an adjusted hazard ratio (HR) of 1.90 (95% CI: 1.12, 3.23). For HCB the HR for the third versus the first tertile of maternal concentration was 1.92 (95% CI: 1.15, 3.21). Weak positive associations were also estimated for PCB-156 and the non-dioxin-like PCBs (PCBs 138, 153, 170, 180). No associations were found for p,p´-DDE.

CONCLUSIONS

Maternal concentrations of PCB-118 and HCB were associated with increased risk of asthma in offspring followed through 20 years of age.

A pilot study for foetal exposure to multiple persistent organic pollutants and the development of infant atopic dermatitis in modern Japanese society

Increasing evidence supports that harmful chemicals accumulating in the human body may pose a significant threat to infant health through foetal exposure. Persistent organic pollutants (POPs) are thought to enhance the risk for later development of allergic disease like atopic dermatitis (AD). However, few studies have evaluated the effect of foetal exposure to various POPs on the development of AD in early infancy. Here, we describe the impact of foetal exposure to a number of POPs on the occurrence of AD in 7-month-old infants. The participants were 81 infants with or without AD who participated in a birth cohort study, where the concentrations of 15 polychlorinated biphenyl (PCBs) congeners, dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethylene (p,p'-DDE), β-hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), cis-nonachlor, trans-nonachlor, mirex, oxychlordane, and 27 polybrominated diphenyl ether (PBDEs) congeners were measured in the umbilical cord tissues collected immediately after birth. At 7 months, 27 of the 81 infants (33.8%) were diagnosed with AD. Of all POPs examined, total concentrations of 27 PBDE congeners were associated with a significantly decreased incidence of AD. Notably, the concentration of 27 PBDEs was significantly lower in AD infants than in non-AD infants (P<0.01), and the risk of AD development decreased with increasing PBDE levels. These results suggest that foetal exposure to PBDEs is a possible contributing factor to reducing AD in early infancy.

Maternal concentrations of persistent organochlorine pollutants and the risk of asthma in offspring: results from a prospective cohort with 20 years of follow-up

BACKGROUND

Previous findings suggest that developmental exposures to persistent organochlorine pollutants (POPs) may be detrimental for the development of the immune system in the offspring. Whether these suspected immunoregulatory effects persist beyond early childhood remains unclear.

OBJECTIVES

The objective of this study was to evaluate the association between maternal serum concentrations of POPs and the risk of asthma in offspring after 20 years of follow-up.

METHODS

A birth cohort with 965 women was formed in 1988-1989 in Aarhus, Denmark. Concentrations of six polychlorinated biphenyls (PCBs) (congeners 118, 138, 153, 156, 170, 180), hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p´-DDE) were quantified in maternal serum (n=872) collected in gestation week 30. Information about offspring use of asthma medications was obtained from the Danish Registry of Medicinal Product Statistics.

RESULTS

Maternal serum concentrations of HCB and dioxin-like PCB-118 were positively associated with offspring asthma medication use after 20 years of follow-up (p for trend<0.05). Compared with subjects in the first tertile of maternal concentration, those in the third tertile of PCB-118 had an adjusted hazard ratio (HR) of 1.90 (95% CI: 1.12, 3.23). For HCB the HR for the third versus the first tertile of maternal concentration was 1.92 (95% CI: 1.15, 3.21). Weak positive associations were also estimated for PCB-156 and the non-dioxin-like PCBs (PCBs 138, 153, 170, 180). No associations were found for p,p´-DDE.

CONCLUSIONS

Maternal concentrations of PCB-118 and HCB were associated with increased risk of asthma in offspring followed through 20 years of age.