Reduction of in utero lead exposures in South African populations: Positive impact of unleaded petrol

PLoS ONE, Volume 12, No. 10, Year 2017

Interprétation

Background: Prenatal exposure to lead (Pb) has been shown to have negative and irreversible health impacts on foetal and early childhood development, affecting morbidity and mortality in adulthood. This study aimed to assess in utero Pb exposure, examine birth outcomes, and identify confounding factors in the large cohort of South African population, following the legislated removal of Pb from petrol. Methods: Lead was measured in the maternal blood, urine and cord blood using Inductive Coupled Plasma Mass spectrometry (ICP-MS). The statistical analyses included Spearman’s correlation, Wilcoxon rank sum (Mann Whitney), Kruskal-Wallis rank tests and multivariate linear regression. Results: Overall, the geometric mean (GM) of Pb in maternal blood (PbB) was 1.32 μg/dL (n = 640; 95% CI, 1.24–1.40). In the subset cohort, the GM of paired maternal PbB and cord blood (PbC) was 1.73 μg/dL (n = 350; 95% CI, 1.60–1.86) and 1.26 μg/dL (n = 317; 95% CI, 1.18–1.35), respectively with a positive correlation between the log PbB and the log PbC (rho = 0.65, p = <0.001). Birth outcomes showed geographical differences in the gestational age (p<0.001), birth length (p = 0.028) and head circumference (p<0.001), Apgar score at 5 min (p<0.001) and parity (p<0.002). In female neonates, a positive association was found between PbC and head circumference (rho = 0.243; p<0.016). The maternal PbB levels were positively correlated with race, educational status, water sources, cooking fuels and use of pesticides at home. Conclusions: This study has demonstrated not only the positive impact that the introduction of unleaded petrol and lead-free paint has had on in utero exposure to Pb in South Africa, but has also contributed new data on the topic, in a region where such data and scientific investigations in this field are lacking. Future research should evaluate if similar effects can be detected in young children and the adult population. Five sites were included in the study: three sites (Sites 1 to 3) were situated in the KwaZulu Natal Province along the Indian Ocean coast (sample collection took place in 2008), and two sites (Sites 4 and 5) were situated in the Western Cape Province along the Atlantic Ocean coast (sample collection took place in 2012 and 2013, respectively (Fig 1). All study sites were rural, except for the urban site of the city of Cape Town (Site 4). The potential candidates recruited for the study were women who were admitted for delivery at the local maternity sections at public hospitals. Women who agreed to participate in the study signed an informed consent form and agreed to donate blood and urine samples before delivery, and to the collection of cord blood samples after delivery. Participants agreed to answer a socio-demographic questionnaire which also included the topics of diet, lifestyle, and self-reported health status. The dietary part of the questionnaire recorded the frequency of intake of various basic foods during pregnancy. Participants also consented to access and use of hospital birth outcome data (including maternal and neonate characteristics such as weight, length and head circumference, gestational age, Apgar score, as well as birth complications, if any) for research purposes. In total, 650 women answered the questionnaire and 640 donated pre-partum blood samples. In a subset cohort of 350 women (from the Indian Ocean site), urine and cord blood samples (n = 317) were also collected. Figure is identical but sites locations were added, and is therefore for representative purposes only. (https://www.cia.gov/library/publications/resources/cia-maps-publications/map-downloads/South%20Africa_Physiography). Ten mL of venous blood was collected before delivery into a BD Vacutainer tube (containing EDTA) and 10 mL of paired cord blood post-partum. Urine (30 mL) was collected before delivery. All samples were stored at -20°C and transported to the South African National Institute for Occupational Health (NIOH) laboratory for analysis. The NIOH participates in the Wadsworth Center–New York State Department of Health Proficiency testing scheme for whole blood and urine. The results obtained are consistently accepted with no indication of bias. The analyses for Pb in the paired maternal and cord whole blood and maternal urine were performed using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) instrument (Agilent 7500ce ICP-MS with an Octopole Reaction System). Contamination-free vessels and procedures were used throughout, and validation of results was accomplished by including certified standards, as well as certified reference quality controls, in the analyses. Digested blood samples were analysed for Pb (208) using the no gas acquisition mode and Tl (205) was used as an internal standard. For quality assurance, two certified blood reference controls, viz. Seronorm TM Trace Elements (Sero LTD., Billingstad, Norway) (Levels 1 and 2) were analysed with every analytical run, at intervals between every 10 samples. The detection limit (three times the standard deviation of all blank samples) for Pb in whole blood was 0.04 μg/dL. Acidified urine samples were analysed using the no gas acquisition mode and Au (197) as an internal standard. For urine, five certified reference controls were analysed with every analytical run in intervals of 12 samples (SeronormTM Trace Elements in urine (urine blank), Lot: OK4636; SeronormTM Trace Elements in urine, Lot: 0511545; UTAK Urine control, Lot: 1170; Lyphochek Urine Metals Control level 1, Lot: 69121; Lyphochek Urine Metals Control level 2, Lot: 69122). The detection limit (three times the standard deviation of all blank samples) for Pb in urine was 0.52 μg/L. Covariate information was obtained during the questionnaire-based interview and from medical records. Maternal weight and height were recorded at the hospital on admission. From the medical records, the following neonate characteristics were retrieved: birth weight (grams), birth length (cm), head circumference (cm) and gestational age (weeks). Pre-term labour was defined as mothers giving birth at less than 37 weeks gestational age. Education was categorised as no education to completed primary school, completed secondary school and any level of tertiary education reached. Maternal tobacco smoking during pregnancy was defined as yes or no. Exposure to environmental tobacco smoke (ETS) was defined as exposure to tobacco smoke from smoking by others in the household. A binary classification was used for exposure to indoor smoke from the burning of fossil fuel (wood and coal) for the purpose of heating or cooking, separating study participants into those exposed to fossil fuel and those not exposed (for example, those using electricity). Dietary questions relating to the intake of proteins, carbohydrates, dairy products, tea, coffee, bottled water, fruits, as well as vine, root and leafy vegetables, were assessed and classified as daily, at least once a week and seldom (both for pre-pregnancy and during pregnancy). The statistical analyses were performed using STATA (StataCorp, 2013. Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Pb was detected in all blood and urine samples. Bivariate analyses between maternal PbB exposure and covariates were evaluated by Spearman’s correlation coefficient, Wilcoxon rank sum (Mann Whitney), Kruskal-Wallis rank tests and linear regression as appropriate. The distribution of Pb levels in maternal blood and in cord blood, were skewed and were log transformed. Multivariate linear regression was carried out using a backward deletion approach, starting with a full model of factors significantly associated with natural logarithm-transformed maternal Pb levels in the bivariate analysis. All statistical tests were two tailed and statistical significance was set at p < 0.05. Ethics approval for the study was obtained from the Human Research Ethics Committee of the University of Witwatersrand in Johannesburg (Protocol no. {"type":"entrez-nucleotide","attrs":{"text":"M10742","term_id":"147973","term_text":"M10742"}}M10742), and from the relevant provincial Departments of Health: the Provincial Department of Health of KwaZulu Natal and the Western Cape Provincial Department of Health. In addition, CEOs of the respective hospitals had to confirm that he/she allowed the research work to proceed. Identical procedures were followed in terms of obtaining consent from participants. Confidentiality was maintained by assigning identification numbers to all study participants. During the informed consent process, it was emphasised that participation was voluntary and could be withdrawn at any time.

Résumé de l’IA

Study Justification:

– Prenatal exposure to lead (Pb) has been shown to have negative and irreversible health impacts on fetal and early childhood development.
– This study aimed to assess in utero Pb exposure, examine birth outcomes, and identify confounding factors in a large cohort of South African population.
– The study focused on the impact of unleaded petrol on reducing in utero Pb exposure.

Study Highlights:

– The introduction of unleaded petrol and lead-free paint has had a positive impact on in utero exposure to Pb in South Africa.
– The study found a positive correlation between maternal blood Pb levels and cord blood Pb levels.
– Geographical differences in birth outcomes were observed, including gestational age, birth length, head circumference, Apgar score, and parity.
– In female neonates, a positive association was found between cord blood Pb levels and head circumference.
– Maternal Pb levels were positively correlated with race, educational status, water sources, cooking fuels, and use of pesticides at home.

Study Recommendations:

– Future research should evaluate if similar effects can be detected in young children and the adult population.
– Further investigation is needed to understand the specific mechanisms through which unleaded petrol reduces in utero Pb exposure.
– Policies should be implemented to further reduce environmental sources of Pb exposure, such as contaminated water sources and the use of pesticides.

Key Role Players:

– Researchers and scientists specializing in environmental health and toxicology.
– Public health officials and policymakers responsible for implementing and enforcing regulations related to lead exposure.
– Healthcare professionals and organizations involved in prenatal care and child development.
– Environmental agencies responsible for monitoring and mitigating environmental sources of lead exposure.

Cost Items for Planning Recommendations:

– Research funding for conducting further studies on the effects of lead exposure and the effectiveness of interventions.
– Resources for monitoring and testing lead levels in various environmental sources, such as water and soil.
– Public education and awareness campaigns to inform the public about the risks of lead exposure and ways to reduce it.
– Implementation and enforcement of regulations related to lead-free petrol, lead-free paint, and other sources of lead contamination.
– Training and capacity building for healthcare professionals to identify and address lead exposure in pregnant women and children.

Force de la preuve

The strength of evidence for this abstract is 8 out of 10.
The evidence in the abstract is strong, but there are some areas for improvement. The study design includes a large cohort of South African population and uses rigorous statistical analyses. The results show a positive impact of unleaded petrol on in utero lead exposure. However, the abstract could be improved by providing more specific details about the sample size, the statistical methods used, and the magnitude of the effects observed. Additionally, the abstract could benefit from a clearer statement of the implications and potential next steps for future research.

Abstrait

Five sites were included in the study: three sites (Sites 1 to 3) were situated in the KwaZulu Natal Province along the Indian Ocean coast (sample collection took place in 2008), and two sites (Sites 4 and 5) were situated in the Western Cape Province along the Atlantic Ocean coast (sample collection took place in 2012 and 2013, respectively (Fig 1). All study sites were rural, except for the urban site of the city of Cape Town (Site 4). The potential candidates recruited for the study were women who were admitted for delivery at the local maternity sections at public hospitals. Women who agreed to participate in the study signed an informed consent form and agreed to donate blood and urine samples before delivery, and to the collection of cord blood samples after delivery. Participants agreed to answer a socio-demographic questionnaire which also included the topics of diet, lifestyle, and self-reported health status. The dietary part of the questionnaire recorded the frequency of intake of various basic foods during pregnancy. Participants also consented to access and use of hospital birth outcome data (including maternal and neonate characteristics such as weight, length and head circumference, gestational age, Apgar score, as well as birth complications, if any) for research purposes. In total, 650 women answered the questionnaire and 640 donated pre-partum blood samples. In a subset cohort of 350 women (from the Indian Ocean site), urine and cord blood samples (n = 317) were also collected. Figure is identical but sites locations were added, and is therefore for representative purposes only. (https://www.cia.gov/library/publications/resources/cia-maps-publications/map-downloads/South%20Africa_Physiography). Ten mL of venous blood was collected before delivery into a BD Vacutainer tube (containing EDTA) and 10 mL of paired cord blood post-partum. Urine (30 mL) was collected before delivery. All samples were stored at -20°C and transported to the South African National Institute for Occupational Health (NIOH) laboratory for analysis. The NIOH participates in the Wadsworth Center–New York State Department of Health Proficiency testing scheme for whole blood and urine. The results obtained are consistently accepted with no indication of bias. The analyses for Pb in the paired maternal and cord whole blood and maternal urine were performed using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) instrument (Agilent 7500ce ICP-MS with an Octopole Reaction System). Contamination-free vessels and procedures were used throughout, and validation of results was accomplished by including certified standards, as well as certified reference quality controls, in the analyses. Digested blood samples were analysed for Pb (208) using the no gas acquisition mode and Tl (205) was used as an internal standard. For quality assurance, two certified blood reference controls, viz. Seronorm TM Trace Elements (Sero LTD., Billingstad, Norway) (Levels 1 and 2) were analysed with every analytical run, at intervals between every 10 samples. The detection limit (three times the standard deviation of all blank samples) for Pb in whole blood was 0.04 μg/dL. Acidified urine samples were analysed using the no gas acquisition mode and Au (197) as an internal standard. For urine, five certified reference controls were analysed with every analytical run in intervals of 12 samples (SeronormTM Trace Elements in urine (urine blank), Lot: OK4636; SeronormTM Trace Elements in urine, Lot: 0511545; UTAK Urine control, Lot: 1170; Lyphochek Urine Metals Control level 1, Lot: 69121; Lyphochek Urine Metals Control level 2, Lot: 69122). The detection limit (three times the standard deviation of all blank samples) for Pb in urine was 0.52 μg/L. Covariate information was obtained during the questionnaire-based interview and from medical records. Maternal weight and height were recorded at the hospital on admission. From the medical records, the following neonate characteristics were retrieved: birth weight (grams), birth length (cm), head circumference (cm) and gestational age (weeks). Pre-term labour was defined as mothers giving birth at less than 37 weeks gestational age. Education was categorised as no education to completed primary school, completed secondary school and any level of tertiary education reached. Maternal tobacco smoking during pregnancy was defined as yes or no. Exposure to environmental tobacco smoke (ETS) was defined as exposure to tobacco smoke from smoking by others in the household. A binary classification was used for exposure to indoor smoke from the burning of fossil fuel (wood and coal) for the purpose of heating or cooking, separating study participants into those exposed to fossil fuel and those not exposed (for example, those using electricity). Dietary questions relating to the intake of proteins, carbohydrates, dairy products, tea, coffee, bottled water, fruits, as well as vine, root and leafy vegetables, were assessed and classified as daily, at least once a week and seldom (both for pre-pregnancy and during pregnancy). The statistical analyses were performed using STATA (StataCorp, 2013. Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Pb was detected in all blood and urine samples. Bivariate analyses between maternal PbB exposure and covariates were evaluated by Spearman’s correlation coefficient, Wilcoxon rank sum (Mann Whitney), Kruskal-Wallis rank tests and linear regression as appropriate. The distribution of Pb levels in maternal blood and in cord blood, were skewed and were log transformed. Multivariate linear regression was carried out using a backward deletion approach, starting with a full model of factors significantly associated with natural logarithm-transformed maternal Pb levels in the bivariate analysis. All statistical tests were two tailed and statistical significance was set at p < 0.05. Ethics approval for the study was obtained from the Human Research Ethics Committee of the University of Witwatersrand in Johannesburg (Protocol no. {"type":"entrez-nucleotide","attrs":{"text":"M10742","term_id":"147973","term_text":"M10742"}}M10742), and from the relevant provincial Departments of Health: the Provincial Department of Health of KwaZulu Natal and the Western Cape Provincial Department of Health. In addition, CEOs of the respective hospitals had to confirm that he/she allowed the research work to proceed. Identical procedures were followed in terms of obtaining consent from participants. Confidentiality was maintained by assigning identification numbers to all study participants. During the informed consent process, it was emphasised that participation was voluntary and could be withdrawn at any time.

Matériaux

https://efashare.b-cdn.net/materials/5444bf6a66650a323fbeb704dc45ea370b72942a9a368e1257363c31ce3be030/pone.0186445.s001.docx

Innovations

Based on the provided information, here are some potential innovations that can be used to improve access to maternal health:

1. Implementation of lead-free petrol: The study highlights the positive impact of unleaded petrol on reducing in utero lead exposure. Expanding the use of lead-free petrol in other regions can help improve maternal health outcomes by reducing the risk of negative health impacts on fetal and early childhood development.

2. Increased awareness and education: Educating pregnant women about the importance of avoiding lead exposure and providing information on sources of lead contamination can help them make informed choices to protect themselves and their unborn babies. This can be done through community outreach programs, prenatal care visits, and public health campaigns.

3. Improved prenatal screening: Implementing routine prenatal screening for lead exposure can help identify women at risk and provide appropriate interventions and support. This can be done by including lead screening as part of standard prenatal care and ensuring that healthcare providers are trained to identify and address lead exposure.

4. Strengthening environmental regulations: Enhancing regulations and enforcement to reduce lead contamination in the environment can have a significant impact on maternal health. This can include stricter controls on lead-based paint, water quality monitoring, and reducing exposure to lead in other common sources such as food and consumer products.

5. Collaborative efforts: Collaboration between healthcare providers, public health agencies, and community organizations is essential to address the complex issue of maternal lead exposure. By working together, these stakeholders can develop comprehensive strategies, share resources, and implement interventions that target the specific needs of the population.

It is important to note that these recommendations are based on the specific context of the study mentioned and may need to be adapted to different regions and settings.

AI Innovations Description

The recommendation to improve access to maternal health based on the described study is to continue the implementation of unleaded petrol and lead-free paint in South Africa. This study has shown the positive impact of these measures on reducing in utero lead exposure in the population. By reducing lead exposure, the study suggests that there can be improvements in birth outcomes, such as gestational age, birth length, head circumference, and Apgar score.

To further develop this recommendation into an innovation, it would be important to focus on the following steps:

1. Raise awareness: Educate the public, especially pregnant women and healthcare providers, about the harmful effects of lead exposure during pregnancy and the benefits of using unleaded petrol and lead-free paint.

2. Policy advocacy: Advocate for the implementation and enforcement of regulations that require the use of unleaded petrol and lead-free paint in all regions of South Africa. This can be done through collaboration with government agencies, non-profit organizations, and other stakeholders.

3. Monitoring and evaluation: Establish a system to monitor and evaluate the effectiveness of the implementation of unleaded petrol and lead-free paint in reducing lead exposure during pregnancy. This can involve regular testing of maternal blood, urine, and cord blood samples to assess lead levels.

4. Research and innovation: Conduct further research to understand the long-term effects of reduced lead exposure on maternal and child health outcomes. This can include studying the impact on cognitive development, neurobehavioral function, and overall health in children as they grow older.

5. Collaboration and partnerships: Foster collaboration and partnerships between government agencies, healthcare providers, researchers, and community organizations to ensure a comprehensive approach to improving access to maternal health and reducing lead exposure.

By implementing these recommendations, South Africa can continue to make progress in improving access to maternal health and reducing the negative impacts of lead exposure on maternal and child health.

AI Innovations Methodology

Based on the provided information, the study focused on assessing in utero lead exposure and its impact on birth outcomes in South African populations. The study utilized various methods, including measuring lead levels in maternal blood, urine, and cord blood, as well as collecting socio-demographic data through questionnaires. Statistical analyses were performed to examine correlations and associations between lead exposure and various factors.

To improve access to maternal health, the following innovations could be considered:

1. Mobile Clinics: Implementing mobile clinics equipped with necessary medical equipment and staffed by healthcare professionals can bring maternal health services closer to rural and remote areas, ensuring better access to prenatal care, screenings, and interventions.

2. Telemedicine: Utilizing telemedicine technologies, such as video consultations and remote monitoring devices, can enable pregnant women to receive medical advice and support from healthcare providers without the need for physical visits, particularly in areas with limited healthcare facilities.

3. Community Health Workers: Training and deploying community health workers who can provide basic prenatal care, education, and support to pregnant women in their communities can improve access to maternal health services, especially in underserved areas.

4. Health Information Systems: Implementing robust health information systems that can track and monitor maternal health indicators, such as prenatal visits, screenings, and birth outcomes, can help identify gaps in access and enable targeted interventions to improve maternal health outcomes.

To simulate the impact of these recommendations on improving access to maternal health, a methodology could include the following steps:

1. Define Key Indicators: Identify key indicators that reflect access to maternal health, such as the number of prenatal visits, percentage of women receiving prenatal screenings, and birth outcomes.

2. Baseline Data Collection: Collect baseline data on the identified indicators from the target population or representative sample. This can be done through surveys, medical records, or existing data sources.

3. Introduce Innovations: Implement the recommended innovations, such as mobile clinics, telemedicine, community health workers, and health information systems, in the target areas or communities.

4. Data Collection Post-Implementation: Collect data on the same indicators after the implementation of the innovations. This can be done through follow-up surveys, medical records, or monitoring systems.

5. Comparative Analysis: Compare the baseline data with the post-implementation data to assess the impact of the innovations on the identified indicators. Statistical analysis can be performed to determine if there are significant improvements in access to maternal health.

6. Evaluation and Adjustment: Evaluate the results and identify areas for improvement. Adjust the innovations and interventions based on the findings to further enhance access to maternal health.

By following this methodology, it would be possible to simulate the impact of the recommended innovations on improving access to maternal health and assess their effectiveness in the target population.

Auteurs et co-auteurs

Statistics:

Citations: 7

Authors: 4

Identifiers:

DOI: 10.1371/journal.pone.0186445

Research Areas:

Environmental, Health System and Policy, Maternal Access, Maternal and Child Health, Quality of Care, Sexual and Reproductive Health, Social Determinants, Substance Abuse

Study Countries:

South Africa

Study Design:

Cohort Study, Cross Sectional Study, Exploratory Study

Study Approach:

Mixed-methods, Qualitative, Quantitative

Participants Gender:

Female

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