Average Blood Lead Concentration Research Articles

Health risk assessment of workers exposed to lead dust in informal e-waste recycling workshops

ABSTRACT Informal recycling of electronic waste (e-waste) has attracted significant attention due to its economic benefits and rapid growth rate in many parts of the world. Unfortunately, unsafe conditions of recycling workshops possess chronic exposure to workers and lead to elevated blood lead concentrations (BLCs). Upon measuring the lead concentration in the dust of recycling workshops and the e-wastes in southwestern region of Iran, the related health risks were assessed in 30 exposed workers and 30 non-exposed habitants cases based on the determination of BLC. The average BLCs in exposed workers and non-exposed habitants cases were 24 μg/dL and 7 μg/dL, respectively. The geo-accumulation index (Igeo) revealed heavy contamination of dust in informal e-waste recycling workshops (IERWs) (5023 μg/kg) and significantly lower levels in unexposed areas (49 μg/kg). Health risk assessment indicated that lead exposure from IERWs appears to be a potential threat to workers and indirectly to their families.

Blood Lead Concentrations and Mortality in Korean Adults: the Korea National Health and Nutrition Examination Survey with Mortality Follow-Up.

Previous studies have consistently reported an increase in mortality risk, even at low levels of blood lead. The average blood lead concentration in the Korean population has steadily decreased but is still higher than that of developed countries. The purpose of this study was to examine the associations between mortality and blood lead concentrations for adults in Korea. We used the Korea National Health and Nutrition Examination Survey (2008–2013) linked Cause of Death data, which are followed by 2018. A total of 7308 subjects who aged over 30 at the baseline examination were included in the analyses. Cox proportional hazard model was used to estimate the hazard ratios of mortality from non-accidental causes and cancer mortality. The estimated hazard ratios (95% CI) for comparison of the second and third tertile group with the lowest tertile group were 2.01 (1.20, 3.40) and 1.91 (1.13, 3.23) for non-accidental mortality and 3.42 (95% CI: 1.65, 7.08) and 2.27 (95% CI: 1.09, 4.70) for cancer mortality, respectively. The dose–response relationship also showed significant increase in the risk of mortality at blood lead level between 1.5 and 6.0 μg/dL. Our findings suggest that potent policies to lower lead exposure are required for the general Korean population.

Potential dietary factors for reducing lead burden of Chinese preschool children.

Dietary approaches to treat children's low lead exposure are implemented routinely in China, while evidence for the effect could not be provided until now. The aim of this study was to examine the relationship between diets including nutrition supplementation and blood lead level of preschool children of China. In total, 17,859 preschool children from 14 cities were recruited, and their social-demography, living environment, and dietary intakes were collected, and capillary blood sample was tested for lead concentration. The average blood lead concentration was 34.5 μg/L, and after adjusting children's social-demography factors, the consumption of milk or dairy production, fruits, and calcium supplementation had negative dose-response relationships with blood lead level. Conversely, intake of iron-rich food and supplementation was not associated. Further studies are needed to prove the causal relationships.

Inverse association between intelligence quotient and urinary retinol binding protein in Chinese school-age children with low blood lead levels: Results from a cross-sectional investigation

Objectives: Examine the relationship between blood lead concentration and children’s intelligence quotient (IQ) in Chinese children 8–12years old. Participants and methods: This is a cross-sectional study, and participants included 446 children from three primary schools in Jiangsu, China. We collected environmental and genetic information from questionnaires. Blood lead (Pb), manganese (Mn), cadmium (Cd) and selenium (Se) concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). IQ was assessed using the Combined Raven’s Test and then converted to a standard IQ score according to Chinese children’s norm. Morning urine samples were collected to measure retinol binding protein (RBP). Results: The average blood lead concentration was 33.13μgL−1 (geometric mean), and the blood lead concentration (BoxCox transform) was inversely and significantly associated with IQ (r=−0.11, p=0.02). The geometric mean of blood Mn, Cd and Se was 7.02μgL−1, 0.18μgL−1 and 94.77μgL−1, respectively. Blood Mn, Cd and Se showed no association with IQ, but all of them associated with urinary RBP. Urinary RBP was identified as a new factor associated with IQ (β=−6.49, p=0.011). Conclusions: Urinary RBP was recognized as a new indicated factor associated with children’s IQ. Mn, Cd and Se exposure might affect urinary RBP concentration and further IQ. Findings also support that blood lead concentrations in 8–12years old children, even <44μgL−1, have a negative association with IQ.

Prospective associations between childhood low-level lead exposure and adult mental health problems: The Port Pirie cohort study

Low-level environmental lead exposure during childhood is associated with poorer emotional/behavioural functioning in later childhood and adolescence. Scarce research has examined whether these apparent effects persist into adulthood. This study is the first to examine prospective associations between lead exposure across early childhood and several common adult mental health problems.Childhood data (including blood lead concentrations) and adult data (from mental health questionnaires and psychiatric interviews) were available for 210 participants (44% males, mean age=26.3 years) from the Port Pirie cohort study (1979–1982 birth cohort).Participants had a mean childhood (to 7 years) average blood lead concentration of 17.2μg/dL. Among females, childhood blood lead showed small significant positive associations with lifetime diagnoses of drug and alcohol abuse and social phobia, and with anxiety, somatic and antisocial personality problems. For example: for a 10μg/dL blood lead increase, females were 2.84 times (95% CI 1.10, 7.30) more likely to have an alcohol abuse diagnosis. However, adjustment for childhood covariates – particularly stimulation within the home environment – rendered these associations non-significant. No significant or sizeable unadjusted or adjusted associations were seen for males.The associations between early lead exposure and emotional/behavioural functioning in children might persist into adulthood, at least for females. However, it is unclear whether such results arise from residual confounding, or other mechanisms. Interventions that focus on improving the childhood home environment may have a long-term positive impact on adult mental health outcomes. However, more prospective research using large and representative samples is needed to substantiate these results.

Lead levels in umbilical cord blood in Belgium: A cross-sectional study in five maternity units

The average blood lead concentration has significantly decreased over the last two decades among the general population. However, in Belgium, there are still high-risk populations such as groups of pregnant women who have shown elevated lead levels. The objective of this study was to evaluate the current situation of lead cord blood levels and identify sources of lead exposure by a questionnaire survey. The study was conducted in 5 maternity units in Belgium; for each, umbilical cord blood samples were collected from 50 consecutive births. At the same time a questionnaire on possible sources of lead exposure was administered to the mother. The dependent variable was a dichotomous lead level variable (<20 μg/L vs. ≥ 20 μg/L). The factors associated with elevated lead levels (≥ 20 μg/L) were mother's country of origin from south Mediterranean and from Sub-Saharan Africa, mother's educational level, using 'tagine' plates for cooking and using khol for make-up, but, after adjusting for potential confounding factors, only the mother's country origin from south Mediterranean (adjusted odds ratio, 5.51; 95% confidence interval [CI], 1.68-18.08; p=0.005) and from Sub-Saharan Africa (adjusted odds ratio, 8.14; 95% CI, 2.26-29.40; p=0.001) were significantly associated with elevated cord blood lead concentrations (≥ 20 μg/L). The results of this study are similar to those found by a previous study in Belgium in 2004. Sources of exposure are difficult to distinguish with this questionnaire, which might be due to other important sources of exposure that were not included in the questionnaire. Confirmation of these risk factors in future studies could lead to new prevention strategies for populations who are at risk for subsequent lead exposure.

Blood Lead Concentrations &lt; 10 μg/dL and Child Intelligence at 6 Years of Age

BackgroundFew studies provide data directly relevant to the question of whether blood lead concentrations < 10 μg/dL adversely affect children’s cognitive function.ObjectiveWe examined the association between blood lead concentrations assessed throughout early childhood and children’s IQ at 6 years of age.MethodsChildren were followed from 6 months to 6 years of age, with determination of blood lead concentrations at 6, 12, 18, and 24 months, and 3, 4, 5, and 6 years of age. At 6 years of age, intelligence was assessed in 194 children using the Wechsler Preschool and Primary Scale of Intelligence–Revised. We used general linear and semiparametic models to estimate and test the association between blood lead concentration and IQ.ResultsAfter adjustment for maternal IQ, HOME scale scores, and other potential confounding factors, lifetime average blood lead concentration (mean = 7.2 μg/dL; median = 6.2 μg/dL) was inversely associated with Full-Scale IQ (p = 0.006) and Performance IQ scores (p = 0.002). Compared with children who had lifetime average blood lead concentrations < 5 μg/dL, children with lifetime average concentrations between 5 and 9.9 μg/dL scored 4.9 points lower on Full-Scale IQ (91.3 vs. 86.4, p = 0.03). Nonlinear modeling of the peak blood lead concentration revealed an inverse association (p = 0.003) between peak blood lead levels and Full-Scale IQ down to 2.1 μg/dL, the lowest observed peak blood lead concentration in our study.ConclusionsEvidence from this cohort indicates that children’s intellectual functioning at 6 years of age is impaired by blood lead concentrations well below 10 μg/dL, the Centers for Disease Control and Prevention definition of an elevated blood lead level.

Blood Lead Concentrations &lt;10 Micrograms Per Deciliter and Child IQ at Age 6 Years

ISEE-432 Objective: To examine the association between blood lead concentrations assessed throughout early childhood and children's intelligence test scores at age 6 years. Material and Methods: This prospective cohort study followed-up 242 infants and their families from 6 months to 6 years of age, measuring blood lead concentrations at 6, 12, 18, and 24 months, and yearly thereafter. Full-scale performance and verbal IQ at age 6 years was assessed using the Wechsler Preschool and Primary Scale of Intelligence – Revised. At the 6-year follow-up, 194 children (80%) completed IQ testing; complete data were available for 174. Results: Lifetime average blood lead concentrations, based on up to 8 blood samples collected over the 6 month to 6 year age period, averaged 7.2 ìg/dL (median, 6.2 ìg/dL). After adjustment for maternal IQ, HOME scale scores, and other potential confounding factors, lifetime average blood lead concentration was inversely associated with full-scale (P for trend = 0.006) and performance IQ scores (P for trend = 0.002). Compared with children who had lifetime average blood lead concentrations <5 ìg/dL, children with lifetime average concentrations between 5 and 9.9 ìg/dL scored 4.9 points lower on measures of full-scale IQ (91.3 vs. 86.4, P = 0.03). However, in comparison with children with blood lead concentrations between 5 and 9.9 ìg/dL, children with blood lead concentrations ≥10 ìg/dL scored only 2.3 points lower on full-scale IQ, and this difference was not statistically significant (86.4 vs. 84.1, P = 0.34). Verbal IQ scores were marginally associated with lifetime average blood lead concentration, but the dose-response relation was less consistent than it was for full-scale and performance IQ. Conclusions: Children's intellectual functioning at 6 years may be impaired by blood lead concentrations in the range of 5 to 10 ìg/dL, below the current CDC definition of an elevated blood lead level.

Lead neurotoxicity in children: Is prenatal exposure more important than postnatal exposure?

Numerous studies indicate that low-level lead poisoning causes mild mental retardation and low IQ scores in children. The general mean lead intake in the adult European population corresponds to a reassuring 14% (0.5-56%) of the tolerable daily intake: at this low level of exposure only few children (less than 10%) have blood lead levels (PbB) higher than 10 microg/dl, previously considered the PbB of concern. In more recent years data now suggest that even when 'the lifetime average blood lead concentration' is below 10 microg/dl an inverse association exists with intelligence quotient (IQ) scores. Two-thirds (45-75%) of lead in blood, however, comes from long-term tissue stores and this is especially true for newborn infants and pregnant women. Several data suggest that for lead the main toxic event is prenatal exposure: therefore we should focus our attention on maternal lead stores and whenever possible avoid their mobilization during pregnancy. In this regard we should design appropriate studies to confirm whether dietary supplementations can reduce bone resorption and lead mobilization during pregnancy. The hypothesis that the amount of maternal bone lead stores is the relevant parameter for predicting the level of neurotoxicity of this metal gives some optimism for the future: if we study children whose mothers never underwent high environmental pollution (born after the withdrawal of lead from gasoline) and hence have relatively low bone lead stores we could find that, at the population level, lead has little influence on children IQ scores.

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) microg/dL and 2.2 (+/- 0.3) microg/dL for controls. Bone measurements, including all 6 paired subjects, showed tibia lead concentration (+/-SEM) for locksmiths and controls was 27.8 (+/- 2.3) microg/g and 13.7 (+/- 3.3) microg/g, respectively; average calcaneus lead concentration for locksmiths and controls was 31.9 (+/- 3.7) microg/g and 22.6 (+/- 4.1) microg/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 13.1 microg/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.

Impaired Neuropsychological Functioning in Lead-Exposed Children

Neuropsychological functions were assessed in 174 children participating in a longitudinal study of low-level lead exposure. At age 5 1/2 years, children were administered the Working Memory and Planning Battery of the Cambridge Neuropsychological Testing Automated Battery. Measures of sociodemographic characteristics of the family, prenatal and perinatal risk, quality of caregiving and crowding in the home, and maternal and child intelligence were used as covariates to test the hypothesis that children with higher lifetime average blood lead concentrations would perform more poorly on tests of working memory, attentional flexibility, and planning and problem solving. The lifetime average blood lead level in this sample was 7.2 micrograms per deciliter (μg/dL; range: 0-20 μg/dL). Children with greater exposure performed more poorly on tests of executive processes. In both bivariate and multivariate analyses, children with higher lifetime average blood lead concentrations showed impaired performance on the tests of spatial working memory, spatial memory span, intradimensional and extradimensional shifts, and an analog of the Tower of London task. Many of the significant associations remained after controlling for children's intelligence test scores, in addition to the other covariates. These findings indicate that the effects of pediatric lead exposure are not restricted to global indexes of general intellectual functioning, and executive processes may be at particular risk of lead-induced neurotoxicity.

Bone turnover in elderly females and males using bisphosphonate treatment-A pilot study

We undertook a 2 year pilot study in premenopausal and postmenopausal females and male partners in which the subjects were administered a bisphosphonate, alendronate, for 6 months. The aim of the study was to determine how lead isotopes and lead concentrations changed in relation to bone remodelling processes. Each subject had blood and urine samples collected for markers of bone turnover and for lead isotope studies monthly for 7 - 9 months before and then 3 monthly during and for up to 6 months after treatment with alendronate as an agent for inhibiting bone resorption. There were significant decreases in the lead isotope ratio, 206 Pb/ 204 Pb, for the migrant subjects during treatment compared with the pro-treatment period (p<0.01). The average blood lead concentrations in migrant subjects decreased by about 20% during the treatment compared with the pre-treatment period (p<0.01 ). The changes in lead isotopic composition and lead concentration are consistent with a decrease in hone resorption and associated mobilisation of lead during alendronate therapy.

Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter.

Despite dramatic declines in children's blood lead concentrations and a lowering of the Centers for Disease Control and Prevention's level of concern to 10 microg per deciliter (0.483 micromol per liter), little is known about children's neurobehavioral functioning at lead concentrations below this level. We measured blood lead concentrations in 172 children at 6, 12, 18, 24, 36, 48, and 60 months of age and administered the Stanford-Binet Intelligence Scale at the ages of 3 and 5 years. The relation between IQ and blood lead concentration was estimated with the use of linear and nonlinear mixed models, with adjustment for maternal IQ, quality of the home environment, and other potential confounders. The blood lead concentration was inversely and significantly associated with IQ. In the linear model, each increase of 10 microg per deciliter in the lifetime average blood lead concentration was associated with a 4.6-point decrease in IQ (P=0.004), whereas for the subsample of 101 children whose maximal lead concentrations remained below 10 microg per deciliter, the change in IQ associated with a given change in lead concentration was greater. When estimated in a nonlinear model with the full sample, IQ declined by 7.4 points as lifetime average blood lead concentrations increased from 1 to 10 microg per deciliter. Blood lead concentrations, even those below 10 microg per deciliter, are inversely associated with children's IQ scores at three and five years of age, and associated declines in IQ are greater at these concentrations than at higher concentrations. These findings suggest that more U.S. children may be adversely affected by environmental lead than previously estimated.

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.

Interactions between Environmental Lead Exposure and Sociodemographic Factors on Cognitive Development

A total of 375 children who lived in Port Pirie, South Australia, and surrounding towns were followed from birth to ages 11-13 y. Possible interactions between lifetime average blood lead concentration and sociodemographic factors (including gender, parents' occupational prestige [as a surrogate of socioeconomic status], quality of home environment, and maternal intelligence quotient) on children's intelligence quotients were examined. Although no statistically significant interaction between blood lead concentration and any of these covariates was found, the results suggested that-after adjustment for a wide range of covariates--children from socially disadvantaged backgrounds (adjusted regression coefficient = -9.6 intelligence quotient points per log unit of blood lead concentration; 95% confidence interval = -2.5, -17.7) were more sensitive to the effects of lead than those of a higher socioeconomic status (adjusted regression coefficient = -2.9; 95% confidence interval = 3.8, -9.6). In addition, girls (adjusted regression coefficient = -7.4; 95% confidence interval = -1.7, -13.1) were more sensitive to the effects of lead than boys (adjusted regression coefficient = -2.6; 95% confidence interval = 2.9, -8.0). These results were basically consistent with our findings observed at ages 2 y, 4 y, and 7 y.

Lifetime low-level exposure to environmental lead and children's emotional and behavioral development at ages 11-13 years. The Port Pirie Cohort Study.

The Port Pirie Cohort Study is the first study to monitor prospectively the association between lifetime blood lead exposure and the prevalence of emotional and behavioral problems experienced by children. Lead exposure data along with ratings on the Child Behavior Checklist were obtained for 322 11-13-year-old children from the lead smelting community of Port Pirie, Australia. Mean total behavior problem score (95% confidence interval (CI)) for boys whose lifetime average blood lead concentration was above 15 microg/dl was 28.7 (24.6-32.8) compared with 21.1 (17.5-24.8) in boys with lower exposure levels. The corresponding mean scores (95% CI) for girls were 29.7 (25.3-34.2) and 18.0 (14.7-21.3). After controlling for a number of confounding variables, including the quality of the child's HOME environment (assessed by Home Observation for Measurement of the Environment), maternal psychopathology, and the child's IQ, regression modeling predicted that for a hypothetical increase in lifetime blood lead exposure from 10 to 30 microg/dl, the externalizing behavior problem score would increase by 3.5 in boys (95% CI 1.6-5.4), and by 1.8 (95% CI -0.1 to 11.1) in girls. Internalizing behavior problem scores were predicted to rise by 2.1 (95% CI 0.0-4.2) in girls but by only 0.8 (95% CI -0.9 to 2.4) in boys.

Improvement in semen quality associated with decreasing occupational lead exposure

Background Cross-sectional studies have suggested that occupational lead exposure may adversely affect sperm quality. >Methods Sperm quality changes were prospectively assessed in 19 men employed at a car battery plant where efforts were made to decrease the exposure level. The participants delivered monthly samples of semen and venous blood during their employment at the factory. The factory then closed, and additional samples were obtained from 16 of the men. Results Average blood-lead concentrations decreased from 2.03 >mol/l to 0.96 >mol/l during the observation period. Concomitantly, significant improvements were seen in the proportion of motile cells both at sample delivery and after 24 hr, and in penetration. However, the sperm cell concentration and the proportion of morphological abnormalities did not change. Conclusions These results support the notion that occupational lead exposure at currently acceptable levels has a small adverse effect on sperm quality, especially sperm motility, and that this effect is at least partially reversible. Am. J. Ind. Med. 35:257–263, 1999. © 1999 Wiley-Liss, Inc.

Serum Calmodulin Activity in Male Lead-exposed Workers.

Serum calmodulin (CaM) activity was studied in 75 lead-exposed and 21 non-exposed male workers. The lead-exposed workers were divided into groups with low blood lead (BPb < 50 µg/dL) and high blood lead (BPb>/=50 µg/dL). The concentrations of lead, calcium, magnesium, copper, zinc, and free erythrocytic protoporphyrin (FEP) in blood were determined. Serum samples were heated in a water bath (100 degrees C) for 3 minutes and centrifuged for 15 minutes at 4 degrees C (18,000 x g). The supernatants obtained were used to measure CaM activity. The results showed that: 1) Average blood lead concentrations in workers with both low and high levels of exposure were significantly higher than those in controls (p < 0.05). 2) Serum CaM activity in the high-exposure group (31.09 +/- 7.84 µg/dL) was significantly lower than that in controls (78.11 +/- 15.13 µg/dL, p < 0.05). The biological threshold of BPb inhibition of CaM activity was less than 50 µg/dL. 3) Multiple correlation analysis showed a negative dose-response relationship between BPb and CaM activity. The stepwise regression procedure indicated that lead had negative, and calcium and magnesium positive, effects on serum CaM activity. The regression equation was Y = 66.1383 - 1.0857 X&inf1; + 2.9676 X&inf2; + 5.2222 X&inf3; (Y:CaM; X&inf1;:Pb; X&inf2;: Ca; X&inf3;:Mg). These results of the first such study carried out in male lead-exposed workers suggest that lead can inhibit CaM activity in humans.

Lifetime exposure to environmental lead and children's intelligence at 11-13 years: the Port Pirie cohort study

To examine the association between environmental exposure to lead and children's intelligence at age 11-13 years, and to assess the implications of exposure in the first seven years of life for later childhood development. Prospective cohort study. 375 children born in or around the lead smelting town of Port Pirie, Australia, between 1979 and 1982. Children's intelligence quotient (IQ) measured at 11-13 years of age. IQ was inversely associated with both antenatal and postnatal blood lead concentrations. Verbal, performance, and full scale IQ were inversely related to blood lead concentration with no apparent threshold. Multivariate analyses indicated that after adjustment for a wide range of confounders, the postnatal blood lead concentrations (particularly within the age range 15 months to 7 years) exhibited inverse associations with IQ. Strong associations with IQ were observed for lifetime average blood lead concentrations at various ages. The expected mean full scale IQ declined by 3.0 points (95% confidence interval 0.07 to 5.93) for an increase in lifetime average blood lead concentration from 0.48 to 0.96 mumol/l (10 to 20 micrograms/dl). Exposure to environmental lead during the first seven years of life is associated with cognitive deficits that seem to persist into later childhood.

Exposure to environmental lead and visual-motor integration at age 7 years: the Port Pirie Cohort Study.

Early childhood exposure to environmental lead may result in subtle deficits in neuropsychological development. Most studies, however, have reported global measures of development, and the findings have not been consistent. In this report, we examine the association between blood lead concentration and a specific aspect of neuropsychological development, visual-motor integration. Each child in a cohort of 494 children living in and around the lead smelting town of Port Pirie, South Australia, was followed for its first 7 years of life. Serial blood samples were collected at various ages to estimate the lifetime burden of each individual. At the time of each blood sampling, systematic information was obtained on a wide range of other variables relevant to child development. We evaluated visual-motor integration at age 7 with the Beery Developmental Test of Visual-Motor Integration (mean score: 13.4). There was an inverse relation between blood lead concentration and visual-motor performance. After adjustment for potential confounding factors, both prenatal and postnatal blood lead concentrations exhibited a dose-related inverse association with children's visual-motor performance. For an increase in life-time average blood lead concentration from 10 micrograms per dl (0.48 mumol per liter) to 30 micrograms per dl (1.45 mumol per liter), the estimated deficit in children's visual-motor performance was 1.6 points (95% confidence interval = 0.3-2.9). The results indicate that visual-motor integration may be a more sensitive index than global measures of development, such as intelligence quotient, for the assessment of lead effects on child development.