Risk of birth defects in a population exposed to environmental lead pollution

A Systematic Literature Review on the Association Between Toxic and Essential Trace Elements and the Risk of Orofacial Clefts in Infants

Orofacial clefts (OFCs) have been linked to various toxic and essential trace elements (TETEs) worldwide. However, review estimation is absent. Therefore, addressing the hypothesis that TETEs are associated with OFCs is the main area of this review. A systematic literature search was conducted using electronic databases through PubMed, Web of Science, Scopus, Science Direct, and Google Scholar between 2004 and August 2022. The "AND" and "OR" operators were used to make our search results inclusive and restrictive as follows: ("Toxic element*" OR "Heavy metal*") AND ("Toxic element*" OR "Lead OR Arsenic OR Mercury*")) AND ("Essential trace element*" OR "Zinc OR Selenium OR Copper*")) AND ("Orofacial cleft*" OR "Cleft lip*" OR "Cleft palate*") AND ("Infant*" OR "Newborn*" OR "Neonate*")). The presence of toxic elements was linked to the development of OFCs. The results showed that higher levels of toxic elements in various biological sample types were related to increased risks for OFCs. Increased concentrations of essential trace elements (ETEs) lowered the risk of OFCs. Maternal consumption of diets rich in ETEs, including zinc (Zn), selenium (Se), copper (Cu), cobalt (Co), and molybdenum (Mo), was linked to a more pronounced reduction in the risk of OFCs. Based on the findings, it is acceptable to infer that maternal exposure to toxic elements, whether through environmental contaminants or dietary sources, was associated with an elevated risk of OFCs. Furthermore, the study revealed that ETEs exhibited a potential protective role in reducing the incidence of OFCs. This observation highlights the importance of reducing exposure to toxic elements during pregnancy and suggests that optimizing maternal intake of ETEs could be an effective preventive strategy.

Associations Between the Lead Level in Maternal Blood and Umbilical Cord Blood and Congenital Heart Diseases in Offspring

The incidence of congenital heart diseases (CHDs) shows an increasing trend and results in large health burdens in China. However, there have been inconsistent results of the relationship between lead (Pb) level and risk of CHDs. We performed a pair-matched case-control study and included 97 cases and 194 controls to investigate the association between pregnancy Pb exposure and the risk of CHDs in a birth cohort study conducted in Lanzhou, China. The results showed that compared to the lowest Pb tertile, both highest tertile levels of maternal blood and umbilical cord blood Pb were associated with an increased risk of CHDs. The similar significant results were found in cases with isolated CHDs. Compared to both lowest tertiles of Pb level in maternal blood and umbilical cord blood, the highest tertile was associated with an increased risk of CHDs, especially for isolated CHDs. Overall, our study suggests a significant association between pregnancy Pb exposure and risk of CHDs, especially for isolated CHDs. Future studies are needed to elucidate the underlying mechanism.

Social cost of mining-related lead (Pb) pollution in Kabwe, Zambia, and potential remediation measures

Lead (Pb) pollution has been one of the major environmental problems of worldwide significance. It is a latent factor for several fatal illnesses, whereas the exposure to lead in early childhood causes a lifetime IQ loss. The social cost is the concept to aggregate various adverse effects in a single monetary unit, which is useful in describing the pollution problem and provides foundation for the design of interventions. However, the assessment of the social cost is scarce for developing countries. In this study, we focus on the lead pollution problem of a former mining town, Kabwe, Zambia, where mining wastes abandoned near residential areas has caused a critical pollution problem. We first investigated the social cost of lead pollution that future generations born in 2025-2049 would incur in their lifetime. As the channels of the social cost, we considered the lost income from the IQ loss and the lost lives from lead-related mortality. The results showed that the social cost would amount to 224-593 million USD (discounted to the present value). Our results can be considered conservative, lower bound estimates because we focused only on well-identified effects of lead, but the social cost was still substantial. Then we examined several engineering remediation measures. The results showed that the social cost can be reduced (the benefits of remediations) more than the costs of implementing remediation measures. This study is the first to investigate the social cost of mining-related lead pollution problem in developing countries. Our interdisciplinary approach utilises the micro-level economic, health and pollution data and integrates the techniques in economics, toxicology and engineering.

Syringol, a wildfire residual methoxyphenol causes cytotoxicity and teratogenicity in zebrafish model

Natural toxicants, particularly methoxy phenols (MPs) generated by wildfire lignin, can accumulate in the environment, and cause serious health hazards in living organisms. Although the toxicity of MPs such as guaiacol and catechol has recently been described, there is minimal evidence of ecotoxicological effects of syringol. As a result, this study focuses on determining the toxicity by evaluating the cytotoxic and teratogenic effects of syringol in vitro and in vivo in human embryonic kidney (HEK-293) cells and zebrafish embryos, respectively. The ecotoxicity of syringol was predicted to be 63.8 mg/L using the ECOSAR (ECOlogical Structure Activity Relationship) prediction tool, and molecular docking analysis was used to determine the interaction and binding affinities of syringol with human apoptotic proteins in silico. In HEK-293 cells, exposure of syringol (0.5-2 mg/L) has induced cytotoxicity in a concentration-dependent manner. In zebrafish larvae, exposure of syringol (0.5-2 mg/L) has induced dose-dependent embryo toxic effects (or growth abnormalities such as yolk sac edema, pericardial edema, skeletal abnormality, and hyperemia), and changes in growth morphometrics (head height, eye, yolk sac, and pericardial area, heart rate) in particular, the heart rate of larvae was found to be significantly decreased (p<0.001). After a 4-day experimental trial, the accumulated concentration of syringol in zebrafish larvae was confirmed both qualitatively (HPLC-MS - High Performance Liquid Chromatography-Mass spectrometry) and quantitatively (LC-QTOF-HRMS - Liquid Chromatography-Quadrupolar Time of Flight-High Resolution Mass spectrometry). The craniofacial abnormalities induced by syringol exposure (0.5-2 mg/L) were detected as anomalies in cartilaginous development and locomotor deficits using alcian blue staining and locomotor analyses, respectively. Significant increase in oxidative stress parameters (including reactive oxygen species generation, lipid peroxidation, superoxide dismutase, catalase, lactate dehydrogenase and nitric oxide production) (p<0.001) and substantial decrease in glutathione levels were observed (p<0.05) in syringol exposed zebrafish larvae through enzymatic analysis. Additionally, through acridine orange staining and gene expression analyses, syringol (2 mg/L) was found to activate apoptosis in zebrafish larvae. Considering the cytotoxic, embryotoxic (teratogenicity), and oxidative stress-related apoptotic effects of syringol in the zebrafish model, syringol has the potential to emerge as a potent environmental toxicant posing serious health hazards in many living systems; however, further research on its toxicological effects on the actual ecosystem and in higher animal models is required to confirm its consequences.

Maternal proximity to mountain-top removal mining and birth defects in Appalachian Kentucky, 1997–2003

Extraction of coal through mountaintop removal mining (MTR) alters many dimensions of the landscape. Explosive blasts, exposed rock, and coal washing have the potential to pollute air and water. Previous research suggests that infants born to mothers living in areas with MTR have a higher prevalence of birth defects. In this cross-sectional study, we further examine the relationship between MTR activity and several types of birth defects. Maternal exposure to MTR was assessed using remote sensing data from Skytruth, which captures MTR activity in the Central Appalachian region of the United States. Active MTR area was quantified within a five-kilometer buffer surrounding geocoded maternal address captured on birth records for live births to Appalachian Kentucky mothers between 1997 and 2003 (N = 95,581). We assigned high, medium, and low exposure based on the tertile of total MTR area within 5-km, and births with no MTR within this buffer were assigned zero exposure. The presence or absence of a birth defect grouped into six major organ systems was identified using birth records alone. Finally, we applied conditional multiple imputation for variables with missing values before conducting separate multivariable log-binomial regression models for each birth defect group. Prevalence ratio (PR) estimates were adjusted for individual level covariates from birth records. The prevalence of gastro-intestinal defects was significantly higher in birth records with high and low active MTR exposure compared to records with no exposure. (High exposure: PR = 1.99, 95% CI = 1.14–3.47; low exposure PR = 1.88, 95% CI = 1.06–3.31). This study supports some of the existing findings of previous ecological studies. Research addressing the relationship between gastro-intestinal birth defects and MTR coal mining is warranted but should carefully consider temporal dimensions of exposure.

Relationship between maternal heavy metal exposure and congenital heart defects: a systematic review and meta-analysis

Congenital heart defects (CHDs) are one of the major causes of death in infants and young children, and heavy metal exposure during pregnancy is one of the possible risk factors. However, the effect of heavy metal exposure on CHDs is still controversial. We searched English (PubMed, Web of Science) and Chinese (CNKI and WanFang database) databases for relevant articles. The summarized effect sizes and 95% confidence intervals (CIs) were calculated by pooling estimates using the random-effects model. Egger's test was used to estimate publication bias. Heterogeneity among studies was indicated by p-values and I². Finally, we conducted subgroup analyses to elucidate the causes of heterogeneity. Thirteen studies were included in this meta-analysis. A positive association between maternal exposure to heavy metals and CHDs was found. Pooling odds ratios (ORs) for arsenic, cadmium, mercury, and lead were 2.12, 1.30, 1.22, and 2.30, respectively for total CHDs. Regarding CHD subtypes, arsenic was associated with an increased risk of septal defects (OR: 1.82), barium with left ventricular outflow tract obstruction (LVOTO) (OR: 1.15) and septal defects (OR: 1.21), and lead with conotruncal defects (OR: 2.34) and LVOTO (OR: 1.93). A heterogeneous relationship was found between studies using different methods of measurement, which were mainly due to differences in actual exposure levels to heavy metals. This meta-analysis suggests significant associations between arsenic, cadmium, mercury, and lead exposure during pregnancy and an increased risk of specific CHDs in offspring. These findings underscore the importance of heavy metal exposure during pregnancy in the risk of CHDs in offspring.

Attention deficit among preschool and school-aged children living near former metal-processing plants in Romania

Industrial areas affected by high and long-term heavy metal pollution have a great impact on health of the resident population. Children represent a group at high-risk with an increased susceptibility to chronic heavy metal intoxication. Our work included the assessment of attention particularities through a case-control study in pre-school and school-aged children (4-6 years and 8-11 years) from two study areas, Copşa Mică and Zlatna, compared to a non-polluted locality with no history of heavy metal pollution. Copşa Mică and Zlatna are two of the most polluted heavy metals regions in Romania due to non-ferrous metallurgy for a long period of time. Recruitment of participants was made by a random selection of an entire class for each age within the schools and kindergartens from the study areas (Copşa Mică and Zlatna) and from the non-polluted region. Interpretation of data was performed using statistical analysis (ANOVA and Student's t-test). Preschool children (4-6 years) were tested using Wechsler Preschool and Primary Scale of Intelligence (WPPSI) tests, Animal House and labyrinth samples. The results of the attention tests applied to pre-school children were lower in the study areas compared to the control group, but no statistical differences were found. The results of the attention tests applied to children aged between 8 and 11 years (Toulouse-Pieron test and Traffic light test) indicate lower average scores within the study groups from polluted areas, compared to the control group. Differences with statistically significance were registered for the 8 years age group (p = 0.037). In these areas efficient strategies and precise intervention measures are needed in order to limit or remove the heavy metal exposure and protect the human health, especially the groups exposed to a high level of risk.

A cross-sectional study of brownfields and birth defects

BACKGROUND

Brownfields are a multitude of abandoned and disused sites, spanning many former purposes. Brownfields represent a heterogenous yet ubiquitous exposure for many Americans, which may contain hazardous wastes and represent urban blight. Neonates and pregnant individuals are often sensitive to subtle environmental exposures. We evaluate whether residential brownfield exposure is associated with birth defects.

METHODS

Using North Carolina birth records from 2003 to 2015, we sampled 753,195 births with 39,495 defects identified. We examined defect groups and 30 distinct phenotypes. Number of brownfields within 2,000 m of the residential address at birth was summed. We utilized mixed effects multivariable logistic regression models adjusted for demographic and environmental covariates available from birth records, 2010 Census, and EPA's Environmental Quality Index to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

We observed positive associations between cardiovascular and external defect groups (OR [95% CI]: 1.07 [1.02-1.13] and 1.17 [1.01-1.35], respectively) and any brownfield exposure. We also observed positive associations with atrial septal and ventricular septal defects (1.08 [1.01-1.16] and 1.15 [1.03-1.28], respectively), congenital cataracts (1.38 [0.98-1.96]), and an inverse association with gastroschisis (0.74 [0.58-0.94]). Effect estimates for several additional defects were positive, though we observed null associations for most group and individual defects. Additional analyses indicated an exposure-response relationship for several defects across levels of brownfield exposure.

CONCLUSIONS

Our results indicate that residential proximity to brownfields is associated with birth defects, especially cardiovascular and external defects. In-depth analyses of individual defects and specific contaminants or brownfield sites may reveal additional novel associations.

Multidisciplinary Approach for Reestablishing Function and Aesthetic of Unilateral Cleft Lip Defect: A Case Report

Cleft lip and/or cleft palate defects often result in a functional deficiency in the patient's chewing, speech ability, and aesthetic appearance, usually demanding multidisciplinary effort for addressing the aesthetic and functional patient's requirements. This clinical report describes the planned oral rehabilitation of a 46-year-old woman with unilateral cleft lip defect based on the patient's peculiarities and age. Due to limitations concerning bone grafts and implant procedures, as well as orthodontic treatment, the prosthodontic rehabilitation using the metal-ceramic fixed partial denture was chosen. The treatment adequately reestablished the aesthetic and functional activities, positively impacting the patient's quality of life.

Lead exposure in an Italian population: Food content, dietary intake and risk assessment

BACKGROUND AND AIM

Lead is a highly toxic heavy metal released into the environment after natural and anthropogenic activities. Excluding populations in occupations where there is possible lead contamination, food is the major source of human exposure. In this study, we determined lead contamination in food and beverages consumed in a Northern Italy community and performed a health risk assessment.

METHODS

We collected a total of 908 food samples and measured lead levels using inductively coupled plasma mass spectrometry. Using a validated food frequency questionnaire, we assessed the dietary habits and estimated daily lead dietary intakes in a sample of 719 adult individuals. We performed risk assessment using a benchmark dose and margin of exposure approach, based on exposure levels for both adverse effect of systolic blood pressure and chronic kidney disease.

RESULTS

Foods with the highest lead levels include non-chocolate confectionery (48.7 µg/kg), leafy (39.0 µg/kg) and other vegetables (42.2 µg/kg), and crustaceans and molluscs (39.0 µg/kg). The estimated mean lead intake was 0.155 µg/kg bw-day in all subjects, with little lower intakes in men (0.151 µg/kg bw-day) compared to women (0.157 µg/kg bw-day). Top food contributors were vegetables, cereals, and beverages, particularly wine. In relation to risk assessment, the estimated dietary intake was lower than levels associated with cardiovascular risk and nephrotoxicity.

CONCLUSIONS

Our study provides an updated assessment of lead food contamination and dietary exposure in a Northern Italian community. The margin of exposure risk assessment approach suggests that risk of detrimental effects due to dietary lead intake is low in the investigated population. Nonetheless, these exposure levels for adverse effects are not reference health standards, and no safety threshold value can be established for lead. As a consequence, other and more subtle adverse effects may still occur in vulnerable and occupationally exposed individuals, particularly in relation to the nervous system.

Birth defects in Tarnaveni area, Romania - preliminary study results

Background and aims

In the development of any human body, defects may occur, resulting in the occurrence of congenital malformations, also referred to as birth defects. The aim of this preliminary study was to assess the prevalence of birth defects registered during a period of 5 years in Tarnaveni area. As Tarnaveni is located in close proximity to a former chemical plant, a recognized hazardous waste site, we conducted this pilot study to assess the prevalence of birth defects, in order to evaluate the need for a more comprehensive investigation of a potential relation between the exposure to toxic metals contaminating the environmental media as a result of the past industrial activities, and the prevalence of the birth defects in this area.

Methods

We abstracted birth information (gestational age at delivery (GA), birth weight (BW), birth length (BL), head circumference (HC), and major structural birth defects), from medical records at “Dr. Gheorghe Marinescu“ Tarnaveni Municipal Hospital, of the 2010–2014 period. We expressed BW as Z-scores relative to expected mean values at each gestational age for a reference population, calculated the ponderal index, and determined the 5 years birth defects prevalence among live births during the study interval.

Results

The 5 years (2010–2014) prevalence of birth defects, was 3.3% (95% confidence interval (CI): 2.47, 4.09). There were n = 163 (8.7%) preterm deliveries (less than 37 weeks of gestation at delivery), mean birth weight was 3108.3 g (standard deviation (SD) = 517.1), ranging from 450–4600 g, and n = 187 (10%) were low birth weight (LBW) (less than 2500 g). The ponderal index was 2.2 g/cm³ on average (SD = 0.5), with range 1.2–20.7 g/cm³.

Conclusions

While preliminary, our data show a 5 years (2010–2014) prevalence of major structural birth defects among newborns from Tarnaveni area of 3.3%. These pilot results indicate the need for a more comprehensive investigation of a potential relation between the exposure to toxic metals contaminating the environmental media as a result of the past industrial activities and the prevalence of the birth defects in Tarnaveni area.

Association between concentrations of barium and aluminum in placental tissues and risk for orofacial clefts

Natural exposure to and increasing use of barium and aluminum in various products, such as plastics, rubber, and food additives, raise concerns for their potential health impacts on pregnant women and vulnerable fetuses. We investigated whether there are associations between barium and aluminum concentrations in placental tissues and the risk for orofacial clefts (OFCs) in offspring. In this case-control study, we recruited 103 women with OFC-affected pregnancies and 206 women who delivered healthy newborns. Concentrations of barium and aluminum in placental tissues were measured using inductively coupled plasma-mass spectrometry. Information on maternal sociodemographic characteristics and diet was collected via face-to-face interviews using a structured questionnaire. Aluminum concentrations in placental tissues were not associated with OFC risk. However, a higher concentration of barium in placental tissues was associated with an increased risk for OFCs, with an adjusted odds ratio (OR) of 2.42 (95% confidence interval [95% CI] 1.34-4.40) for total cleft lip with or without cleft palate (CL ± P), and 1.90 (95% CI 1.03-3.50) for isolated CL ± P. There was a positive dose-response relationship between placental barium concentrations and OFC risk. Maternal exposure to barium may increase the risk for OFCs in offspring.

Environmental Contaminants and Congenital Heart Defects: A Re-Evaluation of the Evidence

Congenital heart defects (CHDs) are a common birth defect of largely unknown etiology, with high fetal and neonatal mortality. A review of CHDs and environmental contaminant exposure found that meta-analyses showed only modest associations for smoking, vehicle exhaust components, disinfectant by-products and proximity to incinerators, with stronger results from the newer, larger and better quality studies masked by the typical absence of effect in older studies. Recent studies of exposure to agricultural pesticides, solvents, metals and landfill sites also showed associations. Certain contaminants have been associated with certain CHDs, with septal defects being the most common. Frequent methodological problems include failure to account for potential confounders or maternal/paternal preconception exposure, differences in diagnosing, defining and classifying CHDs, grouping of defects to increase power, grouping of contaminants with dissimilar mechanisms, exclusion of pregnancies that result in death or later life diagnosis, and the assumption that maternal residence at birth is the same as at conception. Furthermore, most studies use measurement estimates of one exposure, ignoring the many additional contaminant exposures in daily life. All these problems can distort and underestimate the true associations. Impaired methylation is a common mechanism, suggesting that supplementary folate may be protective for any birth defect.

The effects of lead and aluminum exposure on congenital heart disease and the mechanism of oxidative stress

OBJECTIVES

This study aimed to analyze the association between fetal lead or aluminum exposure and congenital heart disease (CHD) occurrence as well as to explore the mechanism of oxidative stress in heart development.

METHODS

Lead and aluminum concentrations were measured by ICP-MS in umbilical serum. The oxidative stress statuses were analyzed by measuring SOD, GPx and MDA with colorimetric assays.

RESULTS

Higher concentrations of Al were seen in the CHD groups compared to the controls. The risk of CHD occurrence increased markedly in the highly elevated Al group (aOR 2.08, 95%CI 1.11-3.88). With increasing Al and Pb levels, the activity of SOD decreased, and the level of MDA increased. Significantly decreased activity of SOD and GPx were found in the CHD groups (P < 0.05).

CONCLUSION

Fetal aluminum exposure may contribute to CHD occurrence. Oxidative stress was related to the concentration of Pb and Al, which may be involved in the occurrence of CHD.

Prevalence of Congenital Heart Disease among Infants from 2012 to 2014 in Langfang, China

Background:

Congenital heart disease (CHD) is the most common congenital malformations with high mortality and morbidity. The prevalence of CHD reported previously ranged from 4 per 1000 live births to 50 per 1000 live births. In this cross-sectional study, we aimed to document the prevalence of CHD in Langfang district of Hebei Province, China by analyzing data collected by hospitals located in 11 the counties of the district, as supported by a public health campaign.

Methods:

A total of 67,718 consecutive 3-month-old infants were included from July 19, 2012 to July 18, 2014. Structural abnormalities were diagnosed based on echocardiography findings, including two-dimensional and color Doppler echocardiography results.

Results:

Of the 67,718 infants, 1554 were found to have cardiac structural abnormalities. The total prevalence of CHD was 22.9 per 1000 live births, a value significantly higher than the previously reported prevalence of 8 cases per 1000 live births. The top five most common cardiac abnormalities were as follows: atrial septal defect (ASD, 605 cases, 8.93‰); ventricular septal defect (550 cases, 8.12‰); patent ductus arteriosus (228 cases, 3.37‰); pulmonary stenosis (66 cases, 0.97‰); and tetralogy of Fallot (32 cases, 0.47‰). The CHD prevalence differed by gender in this study (χ² = 23.498, P < 0.001), and the majority of ASD cases were females. Regional differences in prevalence were also found (χ² = 24.602, P < 0.001); a higher prevalence was found in urban areas (32.2 cases per 1000 live births) than in rural areas (21.1 cases per 1000 live births). There was a significant difference in the prevalence of CHD in preterm versus full-term infants (χ² = 133.443, P < 0.001). Prevalence of CHD in infants of maternal aged 35 years or over was significantly higher (χ² = 86.917, P < 0.001).

Conclusions:

The prevalence of CHD in Langfang district was within the range reported using echocardiography. Echocardiography can be used to early diagnose the CHD.

Birth defects in infants born to employees of a microelectronics and business machine manufacturing facility

BACKGROUND

Concerns about solvent releases from a microelectronics/business machine manufacturing facility in upstate New York led to interest in the health of former workers, including this investigation of birth defects in children of male and female employees.

METHODS

Children born 1983 to 2001 to facility employees were enumerated and matched to New York State's Congenital Malformations Registry. Reported structural birth defects were compared with numbers expected from state rates (excluding New York City), generating standardized prevalence ratios (SPRs). Exposure assessors classified employees as ever/never potentially exposed at the facility to metals, chlorinated hydrocarbons, and other hydrocarbons during windows critical to organogenesis (female workers) or spermatogenesis (male workers). Among workers, adjusted prevalence ratios were generated to evaluate associations between potential exposures and specific birth defects.

RESULTS

External comparisons for structural defects were at expectation for infants of male workers (SPR = 1.01; 95% confidence interval [CI], 0.77-1.29; n = 60) and lower for births to female workers (SPR = 0.84; 95% CI, 0.50-1.33; n = 18). Among full-term infants of male workers, ventricular septal defects (VSDs) were somewhat elevated compared with the general population (SPR = 1.58; 95% CI, 0.99-2.39; n = 22). Within the cohort, potential paternal metal exposure was associated with increased VSD risk (adjusted prevalence ratio = 2.70; 95% CI, = 1.09-6.67; n = 7).

CONCLUSION

While overall SPRs were near expectation, paternal exposure to metals (primarily lead) appeared to be associated with increased VSD risk in infants. Take-home of occupational exposures, nonoccupational exposures, and chance could not be ruled out as causes. Case numbers for many defects were small, limiting assessment of the role of occupational exposures. Birth Defects Research (Part A) 106:696-707, 2016. © 2016 Wiley Periodicals, Inc.

Maternal lead exposure and risk of congenital heart defects occurrence in offspring

Maternal lead exposure may be harmful to fetal development. However, sufficient evidence was lacked about the risk on cardiac development in offspring. To explore the association between maternal lead exposure and risks of congenital heart defects (CHDs) occurrence in fetuses, a case-control study was adopted during pregnant women making antenatal examinations. The maternal hair lead levels were measured by using inductively coupled plasma mass spectrometry (ICP-MS), and logistic regression analysis was used to calculate the odds ratio (OR). Three hundred and sixteen cases and 348 controls were eligible to the study. The median level of lead in maternal hair of case (0.670ng/mg) was significantly higher (AOR 3.07, 95% CI 2.00-4.72) than that of the control (0.461ng/mg), including the CHD cases with or without extracardiac malformations (AOR 3.55, 2.94, respectively). Maternal lead exposure is associated with the risk of some subtypes of CHDs occurrence in offspring. The potential dose-response relationship is also presented.

Preconception care: caffeine, smoking, alcohol, drugs and other environmental chemical/radiation exposure

INTRODUCTION

As providing health education, optimizing nutrition, and managing risk factors can be effective for ensuring a healthy outcome for women and her yet un-conceived baby, external influences play a significant role as well. Alcohol, smoking, caffeine use and other similar lifestyle factors, have now become an integral part of the daily life of most men and women, who use/misuse one or more of these harmful substances regularly despite knowledge of their detrimental effects. The adverse health outcomes of these voluntary and involuntary exposures are of even greater concern in women of child bearing age where the exposure has the potential of inflicting harm to two generations. This paper is examining the available literature for the possible effects of caffeine consumption, smoking, alcohol or exposure to chemicals may have on the maternal, newborn and child health (MNCH).

METHODS

A systematic review and meta-analysis of the evidence was conducted to ascertain the possible impact of preconception usage of caffeine, tobacco, alcohol and other illicit drugs; and exposure to environmental chemicals and radiant on MNCH outcomes. A comprehensive strategy was used to search electronic reference libraries, and both observational and clinical controlled trials were included. Cross-referencing and a separate search strategy for each preconception risk and intervention ensured wider study capture.

RESULTS

Heavy maternal preconception caffeine intake of >300 mg/d significantly increase the risk of a subsequent fetal loss by 31% (95% CI: 8-58%). On the other hand, preconception alcohol consumption leads to non-significant 30% increase in spontaneous abortion (RR 1.30; 95% CI: 0.85-1.97). Preconception counselling can lead to a significant decrease in the consumption of alcohol during the first trimester (OR 1.79; 95% CI: 1.08-2.97). Periconception smoking, on the other hand, was found to be associated with an almost 3 times increased risk of congenital heart defects (OR 2.80; 95% CI 1.76-4.47). While the review found limited evidence of preconception environmental exposure on maternal, newborn and child health outcomes, occupational exposure in female radiation workers before conception showed an increased impact in risk of early miscarriages.

CONCLUSION

Identification of substance abuse and environmental history during preconception period provides an opportunity to assist women in reducing major health risks and identify key determinants of healthy pregnancy. Studies have shown that the aversion and prevention of exposure feasibility can play an important role in improving the health of women and their families, however, the results should be interpreted with great caution as there were few studies in each section. Therefore, there is a need for more rigorous studies to test the hypotheses.

Association between risk of birth defects occurring level and arsenic concentrations in soils of Lvliang, Shanxi province of China

The risk of birth defects is generally accredited with genetic factors, environmental causes, but the contribution of environmental factors to birth defects is still inconclusive. With the hypothesis of associations of geochemical features distribution and birth defects risk, we collected birth records and measured the chemical components in soil samples from a high prevalence area of birth defects in Shanxi province, China. The relative risk levels among villages were estimated with conditional spatial autoregressive model and the relationships between the risk levels of the villages and the 15 types of chemical elements concentration in the cropland and woodland soils were explored. The results revealed that the arsenic levels in cropland soil showed a significant association with birth defects occurring risk in this area, which is consistent with existing evidences of arsenic as a teratogen and warrants further investigation on arsenic exposure routine to birth defect occurring risk.

Use of toxicogenomics to predict the potential toxic effect of Benzo(a)pyrene on zebrafish embryos: ocular developmental toxicity

Benzo(a)pyrene (BaP) is a representative polycyclic aromatic hydrocarbon (PAH), which is ubiquitous in the environment. The toxic effects of BaP on fish embryos have been described in detail, but some potentially toxic effects of BaP might have been neglected owing to the limitations of traditional techniques. In the present research, global transcriptional patterns were used to study the potentially toxic effects of BaP, as well as its underlying toxicological mechanisms. The expression levels of multiple genes were significantly changed by BaP exposure. The results of ontology assignments and cluster analysis showed that BaP could affect the processes of photoreceptor maintenance and phototransduction. We also conducted an experiment on phototactic response and found that larvae exposed to BaP displayed a decreasing response to light. In addition, BaP exposure decreased the cellular density of the ganglion cell layer (GCL) significantly. These results suggested that BaP exposure induced visual system developmental defects and dysfunction by perturbation of photoreceptor development related genes. Our results were helpful for an understanding of the toxicity of BaP. This study also indicated that microarray analysis was effective for predicting the potential toxicity of chemicals with high sensitivity and accuracy.

Newborns and low to moderate prenatal environmental lead exposure: might fathers be the key?

This study is part of the BioMadrid Project, a bio-monitoring study designed to assess pollutants in the environment surrounding children born in the Madrid region. Our aim in this report is to evaluate the association between prenatal lead exposure and fetal development using three biological samples (maternal and paternal blood lead at around 34 weeks of gestation as well as cord blood lead levels), three biomarkers of effect in cord blood peripheral lymphocytes (micronucleus in binucleated cells, nucleoplasmic bridges, and nuclear buds), and different anthropometrical characteristics at birth. Maternal and cord blood lead were not associated with newborn measurements or genotoxicity biomarkers. In contrast, increases in father blood lead were coupled with lower weight (mean difference (MD), -110.8 g; 95% confidence intervals (95%CI), -235.6 to 6.00; p < 0.10) and shorter abdominal (MD, -0.81 cm; 95%CI, -1.64 to 0.00; p < 0.05) and cephalic (MD, -0.32 cm; 95%CI, -0.65 to 0.00; p < 0.05) circumferences at birth as well as with the presence of nucleoplasmic bridges (odds ratio, 1.03; 95%CI, 1.00 to 1.06; p < 0.05) and nuclear buds (odds ratio, 1.02; 95%CI, 0.99 to 1.04; p < 0.10). These associations were mainly confined to female babies, in whom paternal lead was also inversely associated with length. Our results support the hypothesis that paternal lead exposure may be affecting the development of newborns.

Prosthetic rehabilitation of a patient with a unilateral cleft palate: a clinical report

Cleft palate is a congenital disorder characterized by maxillary growth defect and dental anomalies. Its correction requires an interdisciplinary approach, which includes surgical, orthodontic, and prosthetic treatments. This clinical report describes the prosthetic management of a 19-year-old woman with a unilateral cleft palate defect that had not been closed completely with surgical repair. The deficient maxillary residual anterior ridge was restored with a tooth-supported overdenture that improved her facial appearance, speech, and masticatory functions.

Congenital anomalies among live births in a high environmental risk area--a case-control study in Brindisi (southern Italy)

Maternal exposure to ambient pollution has been increasingly linked to the risk of congenital anomalies (CAs) in the fetus and newborns. Recently, a descriptive study in the high environmental risk city of Brindisi (Italy) revealed an increased prevalence of total CAs, especially congenital heart disease (CHD) and ventricular septal defects (VSDs), both at the local level and in comparison with the pool of EUROCAT registries. This paper concerns a population-based case control study to investigate the association between maternal exposure to air pollutants - sulfur dioxide (SO2) and total suspended particulate (TSP) matter - and the risk of CA. Cases were newborns up to 28 days of age, born to mothers resident in Brindisi between 2001 and 2010, and discharged with a diagnosis of CA. Cases and controls were individually matched according to sex, socio-economic status of the census area of residence of the mother, and year of beginning of pregnancy. Up to four controls were extracted for each case. Concentration data from monitoring stations were used to estimate air pollution exposure. Each case and control was assigned pollutant concentration values as mean and 90th percentile of the daily average values during weeks 3-8 of pregnancy. Exposure as both continuous and categorical variables was considered and a conditional logistic regression model was constructed to quantify the odds ratios of exposure to air pollutants and the occurrence of total CAs, CHDs and VSDs. We found exposure to the 90th percentile of SO2 to be associated with CHDs (p for trend =0.01) and VSDs (p for trend <0.05). Findings for TSP were less consistent. In conclusion, in the studied area, maternal exposure to sulfur dioxide increased risk of CHD.

Phenanthrene causes ocular developmental toxicity in zebrafish embryos and the possible mechanisms involved

Recent studies show that polycyclic aromatic hydrocarbons (PAHs) may be a candidate cause of developmental defects of the retina, but the mechanism is still unclear. We evaluated the mechanism(s) underlying PAH-induced retinal development defects due to exposure to environmental concentrations of Phenanthrene (Phe) in zebrafish. We found that exposure to environmental concentrations of Phe caused obvious morphological changes, developmental retardation, apoptosis, and reduction of cell proliferation in the retina. Our results indicated that Phe could cause visual system developmental defects. Phe exposure up-regulated aryl hydrocarbon receptor (AhR) and microphthalmia-associated transcription factor (Mtif) expression, and down-regulated zinc finger E-box binding homeobox 1 (Zeb1) and paired box 6 (Pax6). Moreover, we demonstrated that AhR was a repressor of Zeb1. We propose that Phe's ocular toxicity is mediated by up-regulating AhR, which then down-regulates Zeb1, in turn inducing Mitf expression while inhibiting Pax6 expression.

Residential proximity to environmental hazards and adverse health outcomes

How living near environmental hazards contributes to poorer health and disproportionate health outcomes is an ongoing concern. We conducted a substantive review and critique of the literature regarding residential proximity to environmental hazards and adverse pregnancy outcomes, childhood cancer, cardiovascular and respiratory illnesses, end-stage renal disease, and diabetes. Several studies have found that living near hazardous wastes sites, industrial sites, cropland with pesticide applications, highly trafficked roads, nuclear power plants, and gas stations or repair shops is related to an increased risk of adverse health outcomes. Government agencies should consider these findings in establishing rules and permitting and enforcement procedures to reduce pollution from environmentally burdensome facilities and land uses.

Paternal occupational exposures and the risk of congenital malformations--a case-control study

OBJECTIVES

This study examined the association between certain paternal occupational exposures during the periconceptional period and the risk of congenital malformations.

MATERIALS AND METHODS

A case-control study was carried out from December 2009 to April 2010; on 242 congenital malformation cases and 270 controls. Paternal occupational exposure to certain workplace hazards was assessed by a detailed questionnaire to evaluate the occupational exposure for both fathers and mothers including pesticides, solvents, welding fumes, lead, working with video display terminals (VDTs) and computer monitors. In addition, the questionnaire assessed the presence of other risk factors such as consanguinity, smoking and history of any maternal diseases during the pregnancy with the child.

RESULTS

The results revealed that the odds of having a child with congenital malformation was higher (P < 0.01) if the father was occupationally exposed to pesticides (OR: 3.42, 95% CI: 1.97-5.92), solvents (OR: 5.63, 95% CI: 2.77-11.42), or welding fumes (OR: 2.98, 0.99-8.54) during the periconceptional period. However, consanguinity (OR: 1.91, 95% CI: 1.25-2.92) was a risk factor of developing congenital malformations among offspring.

CONCLUSION

Control of workplace exposures and adherence to threshold limit values of those hazards should be adopted to minimize the risk of developing congenital malformations among offspring.

Links between environmental geochemistry and rate of birth defects: Shanxi Province, China

The rate of birth defects in Shanxi Province is among the highest worldwide. In order to identify the impacts of geochemical and environmental factors on birth defect risk, samples of soil, water and food were collected from an area with an unusually high rate of birth defects (study area) and an area with a low rate of birth defects (control area) in Shanxi Province, China. Element contents were determined by ICP-OES, and the results were analyzed using a non-parametric test and stepwise regression. Differences in the level and distribution of 14 geochemical elements, namely arsenic (As), selenium (Se), molybdenum (Mo), zinc (Zn), strontium (Sr), iron (Fe), tin (Sn), magnesium (Mg), vanadium (V), calcium (Ca), copper (Cu), aluminum (Al), potassium (K) and sulfur (S) were thus compared between the study and control areas. The results reveal that the geochemical element contents in soil, water and food show a significant difference between the study area and control area, and suggest that the study area was characterized by higher S and lower Sr and Al contents. These findings, based on statistical analysis, may be useful in directing further epidemiological investigations identifying the leading causes of birth defects.

Spatial analysis of neural tube defects in a rural coal mining area

Shanxi province in northern China has one of the highest reported prevalence rates of neural tube defects (NTDs) in the world. The current study selected Heshun, the county with the highest rate of NTDs in Shanxi, as a study area and tested whether residence in a coal mining area was a contributing factor. A NTD cluster was detected in an area within 6 km of the coal mines for almost every year during 1998-2005. Poisson regression analysis revealed that there may be an association between production in coal mines and prevalence of NTDs in coal mine areas. Future work identifying factors independently correlated with NTDs in coal mining regions may provide further insights into the health effects of coal mines on NTDs.

Oral cleft defects and maternal exposure to ambient air pollutants in New Jersey

BACKGROUND

Evidence links exposure to ambient air pollution during pregnancy, particularly gaseous pollutants and particulate matter, to an increased risk of adverse reproductive outcomes though the results for birth defects have been inconsistent.

METHODS

We compared estimated exposure to ambient air pollutants during early pregnancy among mothers of children with oral cleft defects (cases) to that among mothers of controls, adjusting for available risk factors from birth certificates. We obtained ambient air pollutant data from air monitoring sites in New Jersey for carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO(2)), particulate matter <10 microm in aerodynamic diameter (PM10) and particulate matter <2.5 microm in aerodynamic diameter (PM2.5). We used values from the nearest monitor (within 40 km of the residence at birth) for controls, cleft lip with or without cleft palate (CLP) and cleft palate only (CPO).

RESULTS

Based on logistic regression analyses for each contaminant and all contaminants together, there were no consistent elevated associations between selected air pollutants and cleft malformations. Quartile of CO concentration showed a consistent protective association with CPO (p < 0.01). For other contaminants, confidence intervals (95%) of the odds ratios for some quartiles excluded one. CLP showed limited evidence of an association with increasing SO(2) exposure while CPO showed weak associations with increasing O3 exposure.

CONCLUSION

There was little consistent evidence associating cleft malformations with maternal exposure to ambient air pollutants. Evaluating particular pollutants or disease subgroups would require more detailed measurement of exposure and classification of cleft defects.

Maternal residential proximity to waste sites and industrial facilities and conotruncal heart defects in offspring

Most studies of the relationship between maternal residential proximity to sources of environmental pollution and congenital cardiovascular malformations have combined heart defects into one group or broad subgroups. The current case-control study examined whether risk of conotruncal heart defects, including subsets of specific defects, was associated with maternal residential proximity to hazardous waste sites and industrial facilities with recorded air emissions. Texas Birth Defects Registry cases were linked to their birth or fetal death certificate. Controls without birth defects were randomly selected from birth certificates. Distances from maternal addresses at delivery to National Priority List (NPL) waste sites, state superfund waste sites, and Toxic Release Inventory (TRI) facilities were determined for 1244 cases (89.5% of those eligible) and 4368 controls (88.0%). Living within 1 mile of a hazardous waste site was not associated with risk of conotruncal heart defects [adjusted odds ratio (aOR) = 0.83, 95% confidence interval (CI) = 0.54, 1.27]. This was true whether looking at most types of defects or waste sites. Only truncus arteriosus showed statistically elevated ORs with any waste site (crude OR: 2.80, 95% CI 1.19, 6.54) and with NPL sites (crude OR: 4.63, 95% CI 1.18, 13.15; aOR 4.99, 95% CI 1.26, 14.51), but the latter was based on only four exposed cases. There was minimal association between conotruncal heart defects and proximity to TRI facilities (aOR = 1.10, 95% CI = 0.91, 1.33). Stratification by maternal age or race/ethnic group made little difference in effect estimates for waste sites or industrial facilities. In this study population, maternal residential proximity to waste sites or industries with reported air emissions was not associated with conotruncal heart defects or its subtypes in offspring, with the exception of truncus arteriosus.

Oral clefts: a retrospective study of prevalence and predisposal factors in the State of Mexico

The purpose of this study was to up-date the records concerning oral clefts (OCs) encountered at the Child Hospital of the Maternal Infantile Institute of the State of México, and to examine the association of predisposing factors. A retrospective study of the medical records of patients generated over a 5-year period was carried out. A total of 835 files were reviewed, representing 504 boys and 331 girls. The studied variables were the type of oral clefts and predisposing factors. Kendal correlations at P < or = 0.05 and chi-squared at P < or = 0.05 were used to find any associations between variables. The distribution of oral cleft was: cleft lip and palate (CLP) 70%, cleft palate (CP) 21%, cleft lip (CL) 8%, separate cleft lip and cleft palate 1%. The sex ratios were 1.7 for CLP, 1.7 for CL, and 1 for CP. Municipalities with ethnic groups as well as industrial, agricultural and pottery activities showed a high rate of prevalence. Although there was no significant association with birth weight, familial history of clefting, consanguinity, medication usage during pregnancy, or paternal occupational risk, the results suggested that the most severe clefts were proportionally related to these factors. A significant association with maternal and paternal age, abortion rate, and parity was found. Additionally, maternal agricultural activities suggested that pesticide exposure might be a factor.

Development and validation of an infant morbidity index using latent variable models

Birth defect, abnormal condition of the newborn, developmental delay or disability and low birth weight are four major infant morbidity outcomes. Most studies have focused on assessment of the effects of risk factors on each of these outcomes or of the relationship among these outcomes or both. Little attention has been paid to the development of a composite index, which is a summary construct of infant morbidity outcomes. In this paper, we develop extended latent variable (LV) models and modified Gauss-Newton algorithms for multiple multinomial morbidity outcomes with complete responses. By assuming the marginal distribution of the LV to be log-normal, we model the conditional probability of each outcome as a nonlinear function of the LV, which has properties similar to the logistic function. The estimated generalized nonlinear least-square method is used to solve equations for parameters of interest. The models are applied to an infant morbidity data set. A new single variable, called infant morbidity index (IMI) that functions as a summary of four infant morbidity outcomes and represents propensity for infant morbidity, is developed. The validity of this index is then assessed in detail. It is shown that the IMI is correlated with each of the individual outcomes, with infant mortality and with a face-valid index of morbidity outcomes, and can be used in future research as a measure of propensity for infant morbidity.

Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants

This review summarizes the level of epidemiologic evidence for relationships between prenatal and/or early life exposure to environmental chemical contaminants and fetal, child, and adult health. Discussion focuses on fetal loss, intrauterine growth restriction, preterm birth, birth defects, respiratory and other childhood diseases, neuropsychological deficits, premature or delayed sexual maturation, and certain adult cancers linked to fetal or childhood exposures. Environmental exposures considered here include chemical toxicants in air, water, soil/house dust and foods (including human breast milk), and consumer products. Reports reviewed here included original epidemiologic studies (with at least basic descriptions of methods and results), literature reviews, expert group reports, meta-analyses, and pooled analyses. Levels of evidence for causal relationships were categorized as sufficient, limited, or inadequate according to predefined criteria. There was sufficient epidemiological evidence for causal relationships between several adverse pregnancy or child health outcomes and prenatal or childhood exposure to environmental chemical contaminants. These included prenatal high-level methylmercury (CH(3)Hg) exposure (delayed developmental milestones and cognitive, motor, auditory, and visual deficits), high-level prenatal exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related toxicants (neonatal tooth abnormalities, cognitive and motor deficits), maternal active smoking (delayed conception, preterm birth, fetal growth deficit [FGD] and sudden infant death syndrome [SIDS]) and prenatal environmental tobacco smoke (ETS) exposure (preterm birth), low-level childhood lead exposure (cognitive deficits and renal tubular damage), high-level childhood CH(3)Hg exposure (visual deficits), high-level childhood exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (chloracne), childhood ETS exposure (SIDS, new-onset asthma, increased asthma severity, lung and middle ear infections, and adult breast and lung cancer), childhood exposure to biomass smoke (lung infections), and childhood exposure to outdoor air pollutants (increased asthma severity). Evidence for some proven relationships came from investigation of relatively small numbers of children with high-dose prenatal or early childhood exposures, e.g., CH(3)Hg poisoning episodes in Japan and Iraq. In contrast, consensus on a causal relationship between incident asthma and ETS exposure came only recently after many studies and prolonged debate. There were many relationships supported by limited epidemiologic evidence, ranging from several studies with fairly consistent findings and evidence of dose-response relationships to those where 20 or more studies provided inconsistent or otherwise less than convincing evidence of an association. The latter included childhood cancer and parental or childhood exposures to pesticides. In most cases, relationships supported by inadequate epidemiologic evidence reflect scarcity of evidence as opposed to strong evidence of no effect. This summary points to three main needs: (1) Where relationships between child health and environmental exposures are supported by sufficient evidence of causal relationships, there is a need for (a) policies and programs to minimize population exposures and (b) population-based biomonitoring to track exposure levels, i.e., through ongoing or periodic surveys with measurements of contaminant levels in blood, urine and other samples. (2) For relationships supported by limited evidence, there is a need for targeted research and policy options ranging from ongoing evaluation of evidence to proactive actions. (3) There is a great need for population-based, multidisciplinary and collaborative research on the many relationships supported by inadequate evidence, as these represent major knowledge gaps. Expert groups faced with evaluating epidemiologic evidence of potential causal relationships repeatedly encounter problems in summarizing the available data. A major driver for undertaking such summaries is the need to compensate for the limited sample sizes of individual epidemiologic studies. Sample size limitations are major obstacles to exploration of prenatal, paternal, and childhood exposures during specific time windows, exposure intensity, exposure-exposure or exposure-gene interactions, and relatively rare health outcomes such as childhood cancer. Such research needs call for investments in research infrastructure, including human resources and methods development (standardized protocols, biomarker research, validated exposure metrics, reference analytic laboratories). These are needed to generate research findings that can be compared and subjected to pooled analyses aimed at knowledge synthesis.

Major congenital malformations and residential proximity to a regional industrial park including a national toxic waste site: an ecological study

BACKGROUND

Public concern about exposure to emissions from the regional industrial park (IP), including 17 chemical plants and the national industrial toxic waste site, initiated this study of the possible association between major congenital malformations (MCM) and residence near the IP in Israel's Southern District.

METHODS

The study was conducted during the period 1995-2000 and included 63,850 deliveries. Data on deliveries and MCM detected at births were obtained from the regional medical center, and stratified by ethnicity and type of locality. As exposure indicator we used distance categories (proximal and distant) and predominant wind direction from the IP. Distance stratification was based on the geographical distribution of the localities and complaints about the odor related to IP emissions. Based on these complaints, localities up to 20 km from the IP were considered proximal to the IP.

RESULTS

Average rates of MCM were 5.0% and 4.1% for Bedouin and Jewish newborns, respectively. The rate of MCM for Bedouin from proximal localities was significantly greater compared with distant localities (5.6% vs. 4.8%; RR = 1.17 with 95% CI: 1.04-1.29). In the proximal Bedouin permanent localities, the MCM rate reached 8.2 %, which was significantly higher than in distant areas (RR = 1.63, 95% CI: 1.39-1.80). Significant risk increase of central nervous system MCM was found in these localities, compared to distant ones (RR = 2.27, 95% CI: 1.44-3.60). Among newborns from the traditional tribal settlements, proximity to the IP was associated with increased rates of the following MCM: 1) all combined, 2) those associated with chromosomal abnormalities, and 3) those defined as "others unclassified MCM." Comparison of autosomal recessive disease rates by proximity to the IP in Bedouin newborns indicates that the observed increased risk of MCM is not explained by consanguineous marriages. The rates of MCM in the Jewish population were similar among "exposed" and "unexposed" inhabitants.

CONCLUSION

Residential proximity to the IP is associated with increased rates of MCM among Arab-Beduin but not in Jewish populations. These observations indicate the need for public health protection of a vulnerable society in transition, although the relative importance of chemical exposure and health care utilization requires further study.

Parental lead exposure and total anomalous pulmonary venous return

BACKGROUND

Investigators from the Baltimore-Washington Infant Study (BWIS) reported an association between self-reported maternal lead exposure and total anomalous pulmonary venous return (TAPVR) in their offspring. This association was further evaluated in the BWIS population using a more sensitive exposure estimate.

METHODS

Cases included 54 live-born infants with TAPVR; controls were a stratified random sample of 522 live-born infants from the BWIS control group. Parental lead exposure was based on three assessment methods, including: an industrial hygiene assessment, an a priori job exposure matrix, and self-reported exposures. A parent was classified as exposed to lead if he/she was classified as exposed by any one of the assessment methods.

RESULTS

Approximately 17% of case mothers and 11% of control mothers were classified as exposed to lead during the three months prior to conception through the first trimester (odds ratio [OR], 1.57; 95% confidence interval [CI], 0.64-3.47). Among fathers, 61% of case fathers and 46% of control fathers were classified as exposed to lead during the six months prior to conception (paternal critical period) (OR, 1.83; 95% CI, 1.00-3.42). During the paternal critical period, when only the father was exposed compared to neither parent exposed, the OR for any lead exposure and TAPVR was 1.65 (95% CI, 0.84-3.25).

CONCLUSIONS

This study supports a possible association between paternal lead exposure and TAPVR. Further studies are warranted using validated assessment methods for occupational and nonoccupational lead exposures to corroborate this association and to elucidate the possible biological mechanism. Birth Defects Research (Part A), 2004.

The impact of environmental pollution on congenital anomalies

Major congenital anomalies are diagnosed in 2-4% of births. In this paper we review epidemiological studies that have specifically looked at congenital anomalies as a possible outcome of community exposure to chemical exposures associated with environmental pollution. These include studies of drinking water contaminants (heavy metals and nitrates, chlorinated and aromatic solvents, and chlorination by-products), residence near waste disposal sites and contaminated land, pesticide exposure in agricultural areas, air pollution and industrial pollution sources, food contamination, and disasters involving accidental, negligent or deliberate chemical releases of great magnitude. We conclude that there are relatively few environmental pollution exposures for which we can draw strong conclusions about the potential to cause congenital anomalies and, if so, the chemical constituents implicated, to provide an evidence base for public health and clinical practice. A precautionary approach should be adopted at both community and individual level. In order to prevent congenital anomalies, one must reduce exposure to potential teratogens before pregnancy is recognized (i.e. preconceptionally and in the first few weeks of pregnancy). It is a challenge to develop effective strategies for preconceptional care within the primary care framework. Prenatal service providers and counsellors need to be aware of the uncertainties regarding environmental pollution when addressing parental concerns.