Blood lead level and blood pressure during pregnancy in South Central Los Angeles

Paternal Lead Exposure and Pregnancy Outcomes: A Systematic Review and Meta-Analysis

Paternal lead exposure has emerged as a potential contributor to adverse pregnancy outcomes, yet its impact remains underexplored compared to maternal exposure. This systematic review and meta-analysis synthesize evidence on the association between paternal lead exposure and pregnancy outcomes to inform public health interventions and future research. To evaluate the association between paternal lead exposure and adverse pregnancy outcomes, including spontaneous abortion, low birth weight, preterm birth, small-for-gestational-age, and congenital anomalies. A systematic search of PubMed, Scopus, and Google Scholar was conducted up to August 2024. Observational studies examining paternal lead exposure (⩾15 µg/dL) and its effects on pregnancy outcomes were included. Data synthesis adhered to PRISMA 2020 guidelines, and study quality was assessed using the Newcastle-Ottawa Scale. Meta-analysis was performed using a random-effects model to compute pooled odds ratios (ORs) with 95% confidence intervals (CIs). Eleven studies were included in the systematic review, with 7 contributing to the meta-analysis. The pooled OR for congenital anomalies associated with paternal lead exposure was statistically significant (OR = 2.09, 95% CI: 2.09-3.35; P < .01), indicating a strong association. However, no significant associations were observed for other outcomes: spontaneous abortion (OR = 1.11, 95% CI: 0.75-1.64), low birth weight (OR = 0.98, 95% CI: 0.68-1.39), preterm birth (OR = 1.57, 95% CI: 0.61-4.05), and small-for-gestational-age infants (OR = 0.92, 95% CI: 0.78-1.09). Heterogeneity was low for most outcomes, except for spontaneous abortion (I 2 = 39%) and preterm birth (I 2 = 52%). This study highlights a significant association between paternal lead exposure and congenital anomalies, emphasizing the need for occupational and environmental regulations targeting lead exposure among men of reproductive age.

Association of blood lead levels with preeclampsia: A cohort study in China

BACKGROUND

Preeclampsia is the main cause of maternal and perinatal death, especially in developing countries. Multiple studies suggest that blood lead levels in pregnancy are a risk factor for preeclampsia, even with low levels of blood lead. But less knows the dose-effect relationship of preeclampsia in low blood lead levels.

OBJECTIVES

This study aims to assess the association between blood lead levels and preeclampsia and to explore its dose-effect relationship between low blood lead levels and preeclampsia.

METHODS

The retrospective cohort study was consecutively conducted in a comprehensive tertiary hospital in Foshan city of Guangdong Province, China, from August 1, 2019, to November 30, 2019. Blood lead levels were measured in maternal whole blood in 12-27 (+6) weeks of pregnancy, using atomic absorption spectrometer. Preeclampsia diagnosis was ascertained from the electronic medical records system. The risk of preeclampsia was estimated by multivariable logical regression analysis, and a two-stage linear regression model was established to find out the dose-effect.

RESULTS

A total of 2174 people were included in this study, and 59 (2.7%) women developed preeclampsia. The dose-effect analysis revealed a non-linear association between blood lead levels and the risk of preeclampsia, with a cut-off point at 4.2 μg/dl. When blood lead levels were over 4.2 μg/dl, the risk of preeclampsia increased significantly with an increase in blood lead levels (OR = 2.05, 95%CI: 1.50, 2.81). In the multivariate regression models, per 1 μg/dl increment in blood lead levels was associated with 43% higher risk of developing preeclampsia (OR = 1.43,95%CI:1.17,1.74). Moreover, the association between blood lead levels and preeclampsia was stable in different subgroups.

CONCLUSIONS

Low levels of lead exposure had a dose-effect relationship of preeclampsia, with a cut-off point at 4.2 μg/dl. Blood lead levels had a non-linear association with preeclampsia. When the blood lead levels were higher than 4.2 μg/dl, the risk of preeclampsia increases by 105% for every 1 μg/dl increase in blood lead levels.

Association between blood lead level and risk of stroke in Korean adults: a cross-sectional study in the Korea National Health and Nutrition Examination Survey 2008-2013

OBJECTIVES

Although lead is a potential risk factor for cardiovascular diseases such as stroke, research on this association in the Korean population remains limited. Therefore, we aimed to investigate the association between lead level and stroke in Korean adults.

DESIGN

A population-based cross-sectional study.

SETTING

The Korea National Health and Nutrition Examination Survey 2008-2013, which enrolled a representative sample of the Korean population.

PARTICIPANTS

We excluded participants younger than 20 years, missing weight data, pregnant or lactating, and missing blood lead and stroke data. A total of 11 510 participants were included in this analysis.

PRIMARY AND SECONDARY OUTCOME MEASUREMENT

The participants were classified by blood lead concentration into the low-level (≤2.189 µg/dL, n=5756) and high-level (>2.189 µg/dL, n=5754) groups. The main outcome, stroke, was assessed by information from physician diagnosis, prevalence of stroke or treatment for stroke. The ORs and 95% CIs were calculated to evaluate the association between blood lead level and stroke using multivariate logistic regression analysis.

RESULTS

Although blood lead level was not significantly associated with stroke (OR: 1.30, 95% CI: 0.66-2.58) in the multivariate-adjusted model, in individuals with hypertension, the high-level group was 2.36-fold higher odds of stroke (OR: 2.36, 95% CI: 1.02-5.44) compared to that in the low-level group. No association was observed in individuals with normotension (OR: 0.42, 95% CI: 0.13-1.38, p for interaction=0.007).

CONCLUSION

The association between blood lead concentration and stroke may be influenced by hypertension status. Our findings suggest the need for closer attention to lead exposure in patients with hypertension.

Blood lead levels in antenatal women and its association with iron deficiency anemia and adverse pregnancy outcomes

OBJECTIVES

Lead is one of the most toxic heavy metal prevalent in the environment, which affects almost all major organs including heart, brain, intestines, kidneys as well as reproductive organs. It has been known that serum iron deficiency is associated with increased serum lead levels as lead is a particularly pernicious element to iron metabolism. Lead is also known to freely cross the placenta too; hence, this study was planned to determine any association between antenatal iron deficiency anemia (IDA), raised blood lead levels (BPb), and adverse pregnancy outcomes.

MATERIALS AND METHODS

This was an observational study done on 99 antenatal women with IDA and 41 nonanemic antenatal women. Lead levels were assessed in these 140 antenatal women and they were followed for adverse pregnancy outcomes. Chi-square test was used to find a difference in quantitative variables and Pearson's correlation test was used to assess association between BPb and hemoglobin levels.

RESULTS

We found that in 11 out of 99 (11.11%) women with IDA, BPb levels were high as compared to high BPb levels in only 1 out of 41 (2.4%) women without IDA and the high BPb levels ranged from 4 μg/dl-16.9 μg/dl with a mean BPb of 8.1 μg/dl. The difference in BPb among anemic and nonanemic antenatal women was significant (P < 0.05) and there was a negative dose effect relationship between BPb levels and hemoglobin levels. This difference in antenatal outcomes among women with and without high BPb levels was also significant with increased incidence of pre-eclampsia, FGR, and preterm deliveries in women with raised BPb levels. The incidence of NICU admission was also higher in the neonates of mothers with high BPb levels.

CONCLUSIONS

We propose screening of high-risk women based on their social, occupational, environmental, and personal factors, with serum lead levels in the preconception period itself. All public and personal measures must be taken to reduce lead consumption and exposure in the preconception and antenatal period.

Blood Lead Levels in U.S. Women of Childbearing Age, 1976-2016

BACKGROUND

Lead can adversely affect maternal and child health across a wide range of exposures; developing fetuses and breastfeeding infants may be particularly vulnerable. We describe the distribution of blood lead levels (BLLs) in U.S. women of childbearing age and associations with sociodemographic, reproductive, smoking, and housing characteristics over a 40-y period.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) II, NHANES III Phase I and Phase II, and 1999-2016 continuous NHANES were used to describe the distribution of BLLs (given in micrograms per deciliter; 1μg/dL=0.0483μmol/L) in U.S. women 15-49 years of age between 1976 and 2016. For all women with valid BLLs (n=22,408), geometric mean (GM) BLLs and estimated prevalence of BLLs ≥5μg/dL were calculated overall and by selected demographic characteristics. For NHANES II, estimated prevalence of BLLs ≥10 and ≥20μg/dL were also calculated.

RESULTS

The most recent GM BLLs (2007-2010 and 2011-2016, respectively) were 0.81μg/dL [95% confidence interval (CI): 0.79, 0.84] and 0.61μg/dL (95% CI: 0.59, 0.64). In comparison, GM BLLs in earlier periods (1976-1980, 1988-1991, and 1991-1994) were 10.37μg/dL (95% CI: 9.95, 10.79), 1.85μg/dL (95% CI: 1.75, 1.94), and 1.53μg/dL (95% CI: 1.45, 1.60), respectively. In 2011-2016, 0.7% of women of childbearing age had BLLs ≥5μg/dL, and higher BLLs were associated with older age, other race/ethnicity, birthplace outside the United States, four or more live births, exposure to secondhand tobacco smoke, and ever pregnant or not currently pregnant.

DISCUSSION

Lead exposure in U.S. women of childbearing age is generally low and has substantially decreased over this 40-y period. However, based on these estimates, there are still at least 500,000 U.S. women being exposed to lead at levels that may harm developing fetuses or breastfeeding infants. Identifying high-risk women who are or intend to become pregnant remains an important public health issue. https://doi.org/10.1289/EHP5925.

Blood Lead Levels in U.S. Women of Childbearing Age, 1976-2016

BACKGROUND

Lead can adversely affect maternal and child health across a wide range of exposures; developing fetuses and breastfeeding infants may be particularly vulnerable. We describe the distribution of blood lead levels (BLLs) in U.S. women of childbearing age and associations with sociodemographic, reproductive, smoking, and housing characteristics over a 40-y period.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) II, NHANES III Phase I and Phase II, and 1999-2016 continuous NHANES were used to describe the distribution of BLLs (given in micrograms per deciliter; 1μg/dL=0.0483μmol/L) in U.S. women 15-49 years of age between 1976 and 2016. For all women with valid BLLs (n=22,408), geometric mean (GM) BLLs and estimated prevalence of BLLs ≥5μg/dL were calculated overall and by selected demographic characteristics. For NHANES II, estimated prevalence of BLLs ≥10 and ≥20μg/dL were also calculated.

RESULTS

The most recent GM BLLs (2007-2010 and 2011-2016, respectively) were 0.81μg/dL [95% confidence interval (CI): 0.79, 0.84] and 0.61μg/dL (95% CI: 0.59, 0.64). In comparison, GM BLLs in earlier periods (1976-1980, 1988-1991, and 1991-1994) were 10.37μg/dL (95% CI: 9.95, 10.79), 1.85μg/dL (95% CI: 1.75, 1.94), and 1.53μg/dL (95% CI: 1.45, 1.60), respectively. In 2011-2016, 0.7% of women of childbearing age had BLLs ≥5μg/dL, and higher BLLs were associated with older age, other race/ethnicity, birthplace outside the United States, four or more live births, exposure to secondhand tobacco smoke, and ever pregnant or not currently pregnant.

DISCUSSION

Lead exposure in U.S. women of childbearing age is generally low and has substantially decreased over this 40-y period. However, based on these estimates, there are still at least 500,000 U.S. women being exposed to lead at levels that may harm developing fetuses or breastfeeding infants. Identifying high-risk women who are or intend to become pregnant remains an important public health issue. https://doi.org/10.1289/EHP5925.

Interaction between blood lead level and chronic obstructive pulmonary disease (COPD) on risk of heart attack or stroke: USA NHANES, 2013-2014

BACKGROUND

Among all risk factors of cardiovascular disease (CVD), lead is associated with cardiovascular mortality. Besides CVD, blood lead level is also related to the chronic obstructive pulmonary disease (COPD). The inter-relationship of CVD, blood lead level and COPD are not yet studied.

OBJECTIVE

The aim of this study is to examine the interaction of COPD and blood lead level on the occurrence of heart attack.

METHODS

This analyzed data is from the 2013-2014 NHANES. The final analysis included 5736 adults. Survey logistic regression models were built to control confounders. We computed adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

A significant interaction (OR = 0.26, CI = 0.12, 0.56) between COPD and blood lead level on the occurrence of heart attack was observed. Those who had COPD were 4.05 times more likely to have heart attack than those who did not have COPD for 1 μg/dL increase in blood lead level. Similarly, a significant interaction between COPD and lead was found for the occurrence of stroke (OR = 0.44, CI = 0.19,1.00), leading to 1.15 times likely to have stroke than those who did not have COPD for 1 μg/dL increase in blood lead level. For the combined outcome, OR = 0.28 with CI=(0.14, 0.57).

CONCLUSIONS

The low lead level today means more effect of COPD on the occurrence of heart attack and stroke. More studies required to understand the pathways of the association of COPD, CVD and lead due to their shared risk factors.

Association of raised blood lead levels in pregnant women with preeclampsia: A study at tertiary centre

OBJECTIVE

This study aims to find the blood lead levels in pregnant women and its association with pre-eclampsia.

MATERIAL AND METHODS

The study included 44 healthy pregnant females and 23 pre-eclamptic women. Demographic data and common risk factors for lead toxicity were recorded including age, residence, occupation, husband occupation, passive smoking, use of cosmetics, kajal, surma, receiving supplements/vitamins, history of house remodelling, plumbing, source of potable water, paint in house, use of lead-glazed ceramic and pica. Venous blood was collected and lead level was determined by atomic absorption spectrometry.

RESULTS

The mean blood lead level was 2.38 ± 2.43 ug/dL in controls and 3.42 ± 2.18 ug/dL in preeclamptic women which was significantly higher (p = 0.0132). Strong correlation of BLL was observed with blood pressure in pre-eclamptic women. Pre-eclamptic patients were observed to be at increased risk of being lead exposed in terms of occupation and living conditions.

CONCLUSION

Higher blood lead level is associated with increased risk of preeclampsia. Patients should be counselled for lifestyle modification to prevent complications.

Association of low-level blood lead and blood pressure in NHANES 1999-2006

This study investigated whether low blood-lead levels (≤10 μg/dL) were associated with blood pressure (BP) outcomes. The authors analyzed data from National Health and Nutrition Examination Survey 1999-2006 and participants aged 20 years or older. Outcome variables were systolic and diastolic BP measurements, pulse pressure, and hypertension status. Multivariable linear and logistic regressions stratified by race/ethnicity and gender were performed. Blood lead levels (BLL) were significantly correlated with higher systolic BP among black men and women, but not white or Mexican-American participants. BLLs were significantly associated with higher diastolic BPs among white men and women and black men, whereas, a negative association was observed in Mexican-American men that had, also, a wider pulse pressure. Black men in the 90th percentile of blood lead distribution (BLL≥3.50 μg/dL) compared to black men in the 10th percentile of blood lead distribution (BLL≤0.7 μg/dL) had a significant increase of risk of having hypertension (adjusted POR=2.69; 95% CI: 1.08-6.72). In addition, blood cadmium was significantly associated with hypertension and systolic and diastolic blood. This study found that, despite the continuous decline in blood lead in the U.S. population, lead exposure disparities among race and gender still exist.

Heavy metal poisoning and cardiovascular disease

Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.

Low-level lead exposure and elevations in blood pressure during pregnancy

BACKGROUND

Lead exposure is associated with elevated blood pressure during pregnancy; however, the magnitude of this relationship at low exposure levels is unclear.

OBJECTIVES

Our goal was to determine the association between low-level lead exposure and blood pressure during late pregnancy.

METHODS

We collected admission and maximum (based on systolic) blood pressures during labor and delivery among 285 women in Baltimore, Maryland. We measured umbilical cord blood lead using inductively coupled plasma mass spectrometry. Multivariable models were adjusted for age, race, median household income, parity, smoking during pregnancy, prepregnancy body mass index, and anemia. These models were used to calculate benchmark dose values.

RESULTS

Geometric mean cord blood lead was 0.66 μg/dL (95% confidence interval, 0.61-0.70). Comparing blood pressure measurements between those in the highest and those in the lowest quartile of lead exposure, we observed a 6.87-mmHg (1.51-12.21 mmHg) increase in admission systolic blood pressure and a 4.40-mmHg (0.21-8.59 mmHg) increase in admission diastolic blood pressure after adjustment for confounders. Corresponding values for maximum blood pressure increase were 7.72 (1.83-13.60) and 8.33 (1.14-15.53) mmHg. Benchmark dose lower limit values for a 1-SD increase in blood pressure were < 2 μg/dL blood lead for all blood pressure end points.

CONCLUSIONS

A significant association between low-level lead exposures and elevations in maternal blood pressure during labor and delivery can be observed at umbilical blood lead levels < 2 μg/dL.

Blood lead in the 21st Century: The sub-microgram challenge

In the US the dominant sources of lead through much of the 20th Century (eg, vehicular emissions, plumbing, household paint) have been significantly diminished. The reductions in adult and pediatric average blood lead levels in the US have been extraordinary. Progress continues: the US Environmental Protection Agency recently developed a new air standard for lead. In the 21st Century, the average blood lead level in a society may be seen as a marker of the status of their public's health. However, the threat of lead exposure remains a significant public health problem among subpopulation groups in the US and in many less developed countries. This paper examines some of the specific issues involved in the reduction of blood lead in a post-industrial era. These involve the control of the remaining exogenous primary sources, both general (eg, industrial emissions) and specific (eg, at-risk occupations), exogenous secondary sources (eg, contaminated urban soils, legacy lead-based paints), an endogenous source (ie, cumulative body lead burden) and emergent sources.

Mechanism of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a newly recognized disease and is an emerging entity throughout developing and developed countries, including the United States. Therefore, understanding the causes, natural history, diagnosis, and management is important for future therapeutic interventions. The pathogenesis of EoE is still not clear, but a growing body of evidence has established that this condition represents a T-cell-mediated immune response involving several proinflammatory mediators and chemoattractants known to regulate eosinophilic accumulation in the esophagus, such as IL-4, IL-5, IL-3 and eotaxin-1, -2, and -3. Determining the mechanism or mechanisms through which human esophageal-derived factors ultimately induce the functional abnormalities observed, and to which antigens patients who have EoE are sensitized that lead to the manifestation of symptoms, is of significant interest.

Status of children's blood lead levels in Pakistan: implications for research and policy

OBJECTIVES

Data on blood lead levels, sources of lead and health effects were reviewed among children in Pakistan.

METHODS

A systematic review was conducted of published studies found through PubMed, an index of Pakistani medical journals PakMediNet and unpublished reports from governmental and non-governmental agencies in Pakistan.

RESULTS

With the exception of a few studies that had adequate sample sizes and population-based samples, most studies were small and used convenience sampling methods to select study subjects. Overall, blood lead levels declined from 38 microg/dl in 1989 to 15 microg/dl in 2002. The major sources of lead that directly or indirectly resulted in lead exposure of children included: leaded petrol; father's occupation in lead-based industry; leaded paint; traditional cosmetics; and remedies. Apart from leaded petrol, there was no information regarding the level of lead in other sources such as paints and the household environment. Very little information was available regarding the adverse health effects of lead among children.

CONCLUSION

The phasing out of leaded petrol was a commendable mitigation measure undertaken in July 2001 in Pakistan. A comprehensive assessment is now needed urgently to explore other sources of lead contributing to adverse health effects, and to plan intervention options with the ultimate goal of reducing the burden of disease due to lead exposure.

Recommendations for medical management of adult lead exposure

Research conducted in recent years has increased public health concern about the toxicity of lead at low dose and has supported a reappraisal of the levels of lead exposure that may be safely tolerated in the workplace. In this article, which appears as part of a mini-monograph on adult lead exposure, we summarize a body of published literature that establishes the potential for hypertension, effects on renal function, cognitive dysfunction, and adverse female reproductive outcome in adults with whole-blood lead concentrations < 40 microg/dL. Based on this literature, and our collective experience in evaluating lead-exposed adults, we recommend that individuals be removed from occupational lead exposure if a single blood lead concentration exceeds 30 microg/dL or if two successive blood lead concentrations measured over a 4-week interval are > or = 20 microg/dL. Removal of individuals from lead exposure should be considered to avoid long-term risk to health if exposure control measures over an extended period do not decrease blood lead concentrations to < 10 microg/dL or if selected medical conditions exist that would increase the risk of continued exposure. Recommended medical surveillance for all lead-exposed workers should include quarterly blood lead measurements for individuals with blood lead concentrations between 10 and 19 microg/dL, and semiannual blood lead measurements when sustained blood lead concentrations are < 10 microg/dL. It is advisable for pregnant women to avoid occupational or avocational lead exposure that would result in blood lead concentrations > 5 microg/dL. Chelation may have an adjunctive role in the medical management of highly exposed adults with symptomatic lead intoxication but is not recommended for asymptomatic individuals with low blood lead concentrations.

Screening for elevated lead levels in childhood and pregnancy: an updated summary of evidence for the US Preventive Services Task Force

BACKGROUND

In 1996, the US Preventive Services Task Force provided recommendations for routine screening of asymptomatic children and pregnant women for elevated blood lead levels. This review updates the evidence for the benefits and harms of screening and intervention for elevated blood lead in asymptomatic children and pregnant women.

METHODS

We searched Medline, reference lists of review articles, and tables of contents of leading pediatric journals for studies published in 1995 or later that contained new information about the prevalence, diagnosis, natural course, or treatment of elevated lead levels in asymptomatic children aged 1 to 5 years and pregnant women.

RESULTS

The prevalence of elevated blood lead levels among children and women in the United States, like that in the general population, continues to decline sharply, primarily because of marked reductions in environmental exposure, but still varies substantially among different communities and populations. Similar to the findings in 1996, our searches did not identify direct evidence from controlled studies that screening children for elevated blood lead levels results in improved health outcomes, and there was no direct evidence identified from controlled studies that screening improves pregnancy or perinatal outcomes. No new relevant information regarding the accuracy of screening for lead toxicity was identified during the update, and we did not identify evidence that demonstrates that universal screening for blood lead results in better clinical outcomes than targeted screening. Substantial new relevant information regarding the adverse effects of screening and interventions was not identified.

CONCLUSIONS

There is no persuasive evidence that screening for elevated lead levels in asymptomatic children will improve clinical outcomes. For those children who are screened and found to have elevated levels, there is conflicting evidence demonstrating the clinical effectiveness of early detection and intervention.

Assessment of lead exposure risk in locksmiths

Exposure to lead has been well recognized in a number of work environments, but little is known about lead exposure associated with machining brass keys containing lead. The brass that is widely used for key manufacturing usually contains 1.5% – 2.5 % of lead. Six (6) licensed locksmiths and 6 case-matched controls successfully completed the pilot study to assess the prevalence of increased body lead burden of professional locksmiths. We measured both Blood Lead (atomic absorption spectrometry), bone-lead (KXRF) and had each subject complete a health and lead exposure risk questionnaire. One locksmith had not cut keys during the past two years, therefore this subject and case-matched control was excluded from the blood lead analysis only. The average blood-lead concentration (±SEM) for the 5 paired subjects was 3.1 (± 0.4) μg/dL and 2.2 (± 0.3) μg /dL for controls. Bone measurements, including all 6 paired subjects, showed tibia lead concentration (±SEM) for locksmiths and controls was 27.8 (± 2.3) μg /g and 13.7 (± 3.3) μg /g, respectively; average calcaneus lead concentration for locksmiths and controls was 31.9 (± 3.7) μg /g and 22.6 (± 4.1) μg /g, respectively: The t-test shows a significantly higher tibia lead (p<0.05) and blood lead (p<0.05) for locksmiths than for their matched controls, but no significant difference for calcaneus lead (p>0.10). Given that the mean tibia bone lead concentration was 13.1μg/g higher in locksmiths than in their matched controls, this average difference in the two groups would translate to an OR of increased hypertension in locksmiths of between 1.1 and 2.3, based on the published literature. Even with the very small number of subjects participating in this pilot study, we were able to demonstrate that locksmiths had significantly higher current exposure to lead (blood lead concentration) and significantly higher past exposure to lead (tibia lead concentration) than their age, sex and ethnically matched controls. Additional research is needed to fully identify the prevalence and associated risk factors for occupational exposure of lead in this previously understudied profession.

Lead and other trace metals in preeclampsia: a case-control study in Tehran, Iran

To assess the effects of environmental exposures to trace metals on the incidence of preeclampsia, concentrations of lead (Pb), antimony (Sb), manganese (Mn), mercury, cadmium, cobalt and zinc in umbilical cord blood (UCB) and mother whole blood (MWB) were measured in 396 postpartum women without occupational exposure to metals in Tehran, Iran, using inductively coupled plasma mass spectrometry. Mother's ages ranged from 15 to 49 (mean 27) years. Preeclampsia was diagnosed in 31 subjects (7.8%). Levels of Pb, Sb and Mn in UCB were significantly higher in preeclampsia cases [mean+/-SD of 4.30+/-2.49 microg/dl, 4.16+/-2.73 and 46.87+/-15.03 microg/l, respectively] than in controls [3.52+/-2.09 microg/dl, 3.17+/-2.68 and 40.32+/-15.19 microg/l, respectively] (P<0.05). The logistic regression analysis revealed that one unit increase in the common logarithms of UCB concentration of Pb, Sb or Mn led to increase in the risk of preeclampsia several-fold; unit risks (95% CI) were 12.96 (1.57-107.03), 6.11 (1.11-33.53) and 34.2 (1.81-648.04) for Pb, Sb and Mn, respectively (P<0.05). These findings suggest that environmental exposure to Pb, Sb and Mn may increase the risk of preeclampsia in women without occupational exposure; levels of metals in UCB to be sensitive indicators of female reproductive toxicity as compared with those in mother MWB. Further studies are necessary to confirm these findings, especially on Sb and Mn.

Is lead considered as a risk factor for high blood pressure during menopause period among Saudi women?

This case-control study was designed to examine the association between blood lead levels and high blood pressure in a restricted subpopulation, Saudi women who were 45-93-year old, during or after menopausal period and not occupationally exposed to lead. Blood lead levels were assessed in 100 women with hypertension and 85 control subjects. Lead concentrations were measured in the whole blood using flameless atomic absorption spectrophotometry. Blood pressure measurements were performed according to the World Health Organization recommendations. Results revealed that the mean blood lead levels for hypertensive were 47.52+/-39.26 and 45.59+/-28.55 microg/l for controls. Participants were classified according to the median of blood lead levels in order to compute odds ratios. After controlling a number of potential confounding variables, the multiple logistic regression analysis revealed that women with blood lead levels of > or = 38.6 microg/l were 5.27 times more likely to be hypertensive than those with blood lead levels of < 38.6 microg/l, but of borderline significance (p = 0.06). Although such observation might support the hypothesis that the depletion of lead from bones during menopause increases blood lead levels placing women at increased risk for high blood pressure, there is a need for further studies with larger number of subjects. A number of risk factors, which were suspected to influence blood lead levels, were also investigated. Use of Kohl, duration of its use, osteoporosis disease and intake of calcium supplements were significantly associated with blood lead levels.

Relationship between increased blood lead and pregnancy hypertension in women without occupational lead exposure in Tehran, Iran

This study was conducted to assess the relationship between blood lead levels and pregnancy-induced hypertension. Participants were 110 pregnant women, of whom 55 were hypertensive, 27 +/- 5.6 yr of age (mean +/- standard deviation) (range = 17-40 yr); the other 55 women were age- and gravidity-matched normotensive controls. Participants were selected on the basis of their medical history and the results of a questionnaire-based interview. Subjects were at gestational ages 37 +/- 2.5 wk (range = 30-41 wk) and were not occupationally exposed to lead. Blood samples were collected within 24 hr after delivery, and blood lead levels were measured. For the hypertensive cases, blood lead levels were 5.7 +/- 2 microg/dl (range = 2.2-12.6 microg/dl [0.27 +/- 0.10 micromol/l; range = 0.11-0.60 micromol/l]), which were significantly higher than those of the control group (i.e., 4.8 +/- 1.9 microg/dl; range = 1.9-10.6 microg/dl [0.23 +/- 0.09 micromol/l; range = 0.09-0.51 micromol/l]). There were no significant differences in blood lead concentrations among hypertensive subjects with proteinuria (n = 30) and those without proteinuria (n = 25). Results of this study indicated that low-level lead exposure may be a risk factor for pregnancy hypertension.

Factors influencing the difference between maternal and cord blood lead

AIMS

To determine the factors that affect why some infants receive higher exposures relative to the mother's body burden than do others.

METHODS

A total of 159 mother-infant pairs from a cohort of women receiving prenatal care at Magee-Womens Hospital in Pittsburgh, PA from 1992 to 1995 provided blood samples at delivery for lead determination. The difference between cord and maternal blood lead concentration (PbB) and a dichotomous variable indicator of higher cord than maternal PbB, were examined as indicators of relative transfer. Women were interviewed twice during the pregnancy about lifestyle, medical history, calcium nutrition, and physical activity.

RESULTS

Higher blood pressure was associated with relatively greater cord compared with maternal PbB, as was maternal alcohol use. Sickle cell trait and higher haemoglobin were associated with a lower cord relative to maternal blood lead PbB. No association was seen with smoking, physical exertion, or calcium consumption.

CONCLUSION

While reduction in maternal exposure will reduce fetal exposure, it may also be possible to mitigate infant lead exposure by reducing transfer from the pregnant woman. Interventions aimed at reducing blood pressure and alcohol consumption during pregnancy may be useful in this regard.

Lead and other metals in gestational hypertension

OBJECTIVES

To identify any effects that lead, calcium, magnesium, and zinc may have on the development of gestational hypertension.

METHODS

Third-trimester 110 normotensive and 33 gestational hypertension cases were assayed for various metal levels, using standard techniques, including atomic absorption spectrometry.

RESULTS

Gestational hypertension cases showed significantly higher blood lead levels than normotensives. No differences were noticed regarding calcium (ionized and total), magnesium, and zinc levels. Blood lead was significantly related with blood pressure, even after correcting for the body mass indices and age. Blood pressure levels showed no relation to the other analyzed metals. However, the lead:ionized calcium ratio showed a stronger association with blood pressure, than lead alone. Blood lead showed a significant negative relationship with ionized calcium, but none with the other metals.

CONCLUSIONS

Blood lead evidently influenced blood pressure increments and gestational hypertension development. This implies that all efforts should be made to reduce the population's exposure.

Elevated blood lead resulting from maxillofacial gunshot injuries with lead ingestion

PURPOSE

The purpose of this study was to identify the contribution of ingested lead particles to elevated blood lead concentrations in victims of gunshot injury to the maxillofacial region.

PATIENTS AND METHODS

As part of a larger study of the effects of retained lead bullets on blood lead, a retrospective review of study findings was completed on 5 of 8 patients who sustained injuries to the maxillofacial region. These 5 patients were recruited into the larger study within 11 days of injury and showed a penetration path for the projectile that engaged the upper aerodigestive tract. All subjects were recruited from patients presenting for care of their gunshot injuries to a large inner-city trauma center with a retained bullet resulting from a gunshot injury. An initial blood lead level was measured for all recruited patients and repeated 1 to 17 weeks later. Medical history was taken along with a screening and risk factor questionnaire to determine other potential or actual sources (occupational/recreational) of lead exposure. (109)Cd K-shell x-ray fluorescence determinations of bone lead were completed to determine past lead exposure not revealed by medical history and risk factor questionnaire. Radiographs taken of the abdomen and chest, required as a part of the patient's hospital care, were retrospectively reviewed for signs of metallic fragments along the aerodigestive tract.

RESULTS

All 5 patients retained multiple lead pellets or fragments at the site of injury, sustained fractures of the facial bones, and showed increases in blood lead. Three of the 5 study subjects who sustained maxillofacial gunshot injuries involving the mouth, nose, or throat region showed metallic densities along the gastrointestinal tract indicative of ingested bullet fragments. Each patient with ingested bullet fragments showed rapid elevation of blood lead exceeding 25 microg/dL and sustained increases well beyond the time when all ingested fragments were eliminated. A 3-year follow-up on these 3 patients showed significantly sustained elevation of blood lead but less than that observed during the initial 6 months after injury. None of the 5 study subjects showed any evidence of metallic foreign bodies within the tracheobronchial regions indicative of aspiration.

CONCLUSION

Ingestion of lead fragments can result from gunshot injuries to the maxillofacial region and may substantially contribute to a rapid increase in blood lead level. Prompt diagnosis and elimination of ingested lead fragments are essential steps necessary to prevent lead being absorbed from the gastrointestinal tract. Increased blood lead in victims after gunshot injuries must be fully evaluated for all potential sources, including recent environmental exposure, absorption of lead from any remaining bullets in body tissues, and the possibility of mobilization of lead from long-term body stores such as bone.

Blood lead level is associated with elevated blood pressure in blacks

Chronic lead exposure has been associated with elevated blood pressure in epidemiological studies. It is not known whether the previously observed relation between blood lead and hypertension persists after significant reductions have been made in environmental lead contamination. We examined the relation between blood lead levels and blood pressure in a representative sample of 14 952 whites and blacks aged 18 years or older who participated in the Third National Health and Nutrition Examination Survey. Blood lead was measured by atomic absorption spectrophotometry and blood pressure by standard sphygmomanometry. Mean blood lead levels were significantly higher for black men and women (5.4 and 3.4 microg/dL, respectively) compared with white men and women (4.4 and 3.0 microg/dL, respectively). After multivariate adjustment for important covariables, each standard deviation higher blood lead (3.3 microg/dL) was associated with a 0.82 (95% confidence interval [CI], 0.19 to 1.44) mm Hg and a 1.55 (95% CI, 0.47 to 2.64) mm Hg higher systolic blood pressure among black men and women, respectively. In contrast, blood lead level was not associated with blood pressure among white men or women. The multivariate-adjusted odds ratio (95% CI) of hypertension associated with a 1-SD higher level of blood lead was 1.08 (95% CI, 0.99 to 1.19) for black men and 1.39 (95% CI, 1.21 to 1.61) for black women. These findings suggest that increased levels of blood lead remain an important environmental risk factor for elevated blood pressure in blacks.

Blood lead concentrations and pregnancy outcomes

In this study, the authors related blood lead concentrations to Apgar scores, birth weight, gestational age, small-for-gestational age, and hypertension in pregnancy (HIP)/toxemia. Data and blood were collected 4 times during pregnancy from 705 women, aged 12-34 yr. Blood lead concentrations, measured by atomic absorption spectrophotometry, were related to reproductive outcomes, abstracted from medical records. Average blood lead concentrations were 1.2 microgram/dl (standard error = +/- 0.03). Maternal blood lead concentrations were related significantly to HIP/toxemia--before and after adjusting for age, calcium intake, and race/ethnicity (p < .03). Longitudinal regression analyses revealed that blood lead concentrations in women with HIP/toxemia changed by 0.02 microgram/dl for every 0.01 microgram/dl change in women without HIP/toxemia. Maternal blood lead concentration and its change were not significantly associated with other reproductive outcomes. Low levels of maternal blood lead concentrations were significantly associated with HIP/toxemia.

Findings and accomplishments of ATSDR's Superfund-mandated Substance-Specific Applied Research Program

Priority research needs determined by the Agency for Toxic Substances and Disease Registry (ATSDR) for the agencies top-ranked hazardous substances are being filled via regulatory mechanisms, private sector voluntarism, and university-based research. To date, 17 studies have been completed, 12 are ongoing, and 12 are currently planned. Under the direction of the Substance-Specific Applied Research Program (SSARP), ATSDR-supported research has filled research needs that significantly improved the information base available for making appropriate public health decisions. With the knowledge and understanding gained from this research, health professionals are better able to identify and interdict significant exposure and mitigate toxicity when exposure occurs. Thus, the SSARP has played, and continues to play, a vital role in contributing towards improving ATSDR's efforts to meet its mission and goals in environmental public health. In addition to addressing research needs of interest to ATSDR, findings from the program have contributed to the overall scientific knowledge about the effects of toxic substances in the environment.

An epidemiological re-appraisal of the association between blood pressure and blood lead: a meta-analysis

Studies on the possible association between blood pressure and blood lead have reached divergent conclusions. In a previous meta-analysis, a doubling of the blood lead concentration was associated with a 1.0/0.6 mm Hg increase in systolic and diastolic blood pressure (BP). This meta-analysis updates the analysis originally performed in 1994. Articles on the association between BP and blood lead were identified from computer searches from January 1980 to February 2001 using the Medical Literature Analysis and Retrieval System. Of the studies reviewed, 31 provided sufficient details to be considered. The meta-analysis included 58518 subjects recruited from the general population in 19 surveys and from occupationally exposed groups in 12 studies. In all but four studies, the results were adjusted for age, and most studies took into account additional confounding factors such as body mass index and the use of alcohol and medication. Weighted joint P-values were calculated using Stouffer's procedure. The association between BP and blood lead was similar in both men and women. In the combined studies, a two-fold increase in blood lead concentration was associated with a 1.0 mm Hg rise in the systolic pressure (95% CI +0.5 to +1.4 mm Hg; P < 0.001) and with a 0.6 mm Hg increase in the diastolic pressure (95% CI +0.4 to +0.8 mm Hg; P < 0.001). On balance, this meta-analysis suggests that there can only be a weak association between BP and blood lead.

The lead content of blood serum

Serum lead concentrations measured by stable isotope dilution with a thermal ionization mass spectrometer and blood lead concentrations measured by graphite furnace atomic absorption spectrophotometry are reported for 73 women of child bearing age resident in Los Angeles, California. The two quantities are related by the line y=0.00030+0.00241x (r=0.83), where y is serum lead concentration and x is blood lead concentration, both being expressed in units of microg/L. The linearity of the relationship appears to hold to a blood lead concentration of at least 60 microg Pb/L. The slope of the line indicates that lead in serum is 0.24% of that in whole blood in contrast to recent reports of between 0.32 and 0.35% determined by inductively coupled plasma (ICP) mass spectrometry with bismuth used as an internal standard. The discrepancy stems from the ICP mass spectrometer-generated curves not passing through the origin.

The Effects of Retained Lead Bullets on Body Lead Burden

BACKGROUND

Numerous case reports have demonstrated that lead poisoning with potentially fatal consequences can result from retained lead projectiles after firearm injuries. To assess the impact of retained projectiles on subsequent lead exposure in the population, one cannot rely on self-selected cases presenting with symptoms of lead intoxication. This preliminary study seeks to identify increased lead burden and identify risk factors of elevated blood lead levels for individuals with retained lead bullets.

METHODS

Forty-eight patients were originally recruited from gunshot victims presenting for care at the King/Drew Medical Center in Los Angeles, California. An initial blood level was measured for all recruited patients and repeated for the 28 participants available for follow-up, 1 week to 8 months later. Medical history, including a history of prior firearm injuries and other retained projectiles, was taken, along with a screening and risk factor questionnaire to determine other sources of lead (occupational/recreational) to which the patient might have been, or is at present, exposed. The participants also had K-shell x-ray fluorescence determinations of bone lead in the tibia and calcaneus in order to determine past lead exposures not revealed by medical history and risk factor questionnaire. Multivariate models of blood level were made using risk factor and bone lead concentration data.

RESULTS

We demonstrated that blood lead tends to increase with time after injury in patients with projectile retention, and that the increase in significant part depended on the presence of a bone fracture caused by the gunshot.

CONCLUSION

We encountered evidence suggesting that the amount of blood lead increase in time after injury is also dependent on the tibia lead concentration. There were too few cases in the study to fully test the effects of bullet location, or the interaction of bullet location with bone fracture or bullet fragmentation.