History Of Lead Exposure Research Articles

Airborne lead and polychlorinated biphenyls (PCBs) are associated with amyotrophic lateral sclerosis (ALS) risk in the U.S

Amyotrophic lateral sclerosis (ALS) risk is linked to environmental exposures. The National Emissions Inventory (NEI) database compiles mandatory reports of levels of airborne contaminants from a variety of stationary and mobile pollution sources across the U.S. The objective of this study was to identify airborne contaminants that may be associated with ALS etiology for future study. We geospatially estimated exposure to airborne contaminants as risk factors for ALS in a nationwide large de-identified medical claims database, the SYMPHONY Integrated Dataverse®. We extracted zip3 of residence at diagnosis of ~26,000 nationally distributed ALS patients and n = 3 non-ALS controls matched per case for age and sex. We individually aggregated the median levels of each of 268 airborne contaminants recorded in the NEI database for 2008 to estimate local residential exposure. We randomly broke the dataset into two independent groups to form independent discovery and validation cohorts. Contaminants associated with increased ALS risk in both the discovery and validation studies included airborne lead (false discovery rate (FDR) = 0.00077), and polychlorinated biphenyls (PCBs), such as heptachlorobiphenyl (FDR = 3.60E−05). Small aircraft were the largest source of airborne lead, while the PCB emissions came from certain power plants burning biomass, and from industrial boilers. Associations with residential history of lead exposure were confirmed in two additional cohorts (10 year top quartile in New Hampshire/Vermont OR 2.46 95% CI 1.46–2.80, and in Ohio OR 1.60 95% CI 1.28–1.98). The results of our geospatial analysis support neurotoxic airborne metals and PCBs as risk factors for ALS.

Lead poisoning from bench to bed-side

Lead poisoning often presents with non-specific clinical symptoms but specific laboratory and blood film features. A history of lead exposure may be obvious in occupational or environmental exposure, however recreational exposures may be more difficult to identify.

Ultrasonographic measurement of the femoral cartilage thickness in patients with occupational lead exposure.

The objective of the present study is to compare distal femoral cartilage thicknesses of patients with occupational lead exposure with those of healthy subjects by using ultrasonography. A total of 48 male workers (a mean age of 34.8±6.8 years and mean body mass index (BMI) of 25.8±3.1 kg/m(2)) with a likely history of occupational lead exposure and age- and BMI-matched healthy male subjects were enrolled. Demographic and clinical characteristics of the patients, that is, age, weight, height, occupation, estimated duration of lead exposure, and smoking habits were recorded. Femoral cartilage thickness was assessed from the midpoints of right medial condyle (RMC), right lateral condyle (RLC), right intercondylar area (RIA), left medial condyle (LMC), left lateral condyle (LLC), and left intercondylar area (LIA) by using ultrasonography. Although the workers had higher femoral cartilage thickness values at all measurement sites when compared with those of the control subjects, the difference reached statistical significance at RLC (P=0.010), LMC (P=0.001), and LIA (P=0.039). There were no correlations between clinical parameters and cartilage-thickness values of the workers. Subjects with a history of lead exposure had higher femoral cartilage thickness as compared with the healthy subjects. Further studies, including histological evaluations, are awaited to clarify the clinical relevance of this increase in cartilage thickness and to explore the long-term follow-up especially with respect to osteoarthritis development.

Lead exposure is a risk for worsening bone mineral density in middle-aged male workers

Objective: Lead exposure linked to osteoporosis in women. However, there is no direct evidence whether lead exposure has effects on bone metabolism in middle-aged male subjects. Therefore, the present study investigated the relationship between bone mineral densitometry measurements, bone markers, endocrine hormones and blood lead levels.Material and methods: The present study included lead exposure patients (n: 30) and control subjects (n: 32). We recorded information on patient demographics and risk factors of osteoporosis. Blood lead levels were evaluated using Varian AA 240Z atomic absorption spectrophotometry. Bone mineral density measurements were measured using dual-energy X-ray absorptiometry.Results: Each lumbar T and Z scores in the lead exposure group were lower than the control group. There were no significant differences in femur neck and femur total T and Z scores between two groups. Blood lead levels were also negatively correlated with lumbar 2-4 T score, total lumbar T score, lumbar 2-4 Z score and total lumbar Z score. Urinary hydroxyproline and urinary deoxypyridinoline levels in the lead exposure group were significantly higher compared to controls. Blood lead levels were strong, positively correlated with urinary deoxypyridinoline. Endocrine hormone levels and 1,25-dihydroxy-vitamin D3 levels were comparable between lead exposure and control group.Conclusion: Lead exposure in male workers is an important factor for deterioration in bone mineral density. We should be screening blood lead levels and history of lead exposure in male osteoporosis.

Windows of Lead Exposure Sensitivity, Attained Height, and Body Mass Index at 48 Months

To examine longitudinal associations of prenatal, infancy, and early childhood lead exposure during sensitive periods with height and body mass index (BMI). A total of 773 participants were recruited between 1994 and 2005 in Mexico City. Lead exposure history categories were constructed for the prenatal period (maternal patellar lead concentration) and for infancy and childhood (mean child blood lead concentration at birth to 24 months and 30-48 months, respectively). Linear regression models were used to study lead exposure history with height and BMI at 48 months. Mean height at age 48 months was significantly lower in children with a blood lead level exceeding the median during infancy (-0.84 cm; 95% CI, -1.42 to -0.25) than in children with a level below the median. Prenatal lead exposure was not associated with height at 48 months. Results for attained BMI generally trended in the same direction as for height. Our findings suggest an effect of lead exposure early in life on height attainment at 48 months, with the exposure window of greatest sensitivity in infancy.

Diagnosis, Evaluation, and Treatment of Lead Poisoning in General Population

Among the heavy metals, lead still remains the major toxic pollutant of the environment. Human exposure to lead can occur through numerous pathways including air, food, dust, soil, and water. In the present study 14 lead poisoned patients with non-occupational lead exposure were evaluated. They were followed up and compared against the controls with no history of lead exposure. The patients had high blood lead levels and symptoms of weakness, dizziness, abdominal pain, generalized body ache, loss of appetite, and anxiety. Repeated course of chelation therapy helped to bring down their body burden of lead. Alternative sources for lead exposure can cause severe lead poisoning in general population. Screening and medical management of such individuals is very important to identify and eliminate sources of lead. The treatment and management requires a thorough medical evaluation and environmental intervention.

Screening for Blood Lead Levels in Basrah, Southern Iraq

A prospective study over six months (from 1 July to 31 December 2002) measured the level of blood lead in individuals attending Primary Health Centers in the center District of Basrah Governorate. Six hundred and two individuals were selected randomly from those attending seventeen Primary Health Centers in the center of Basrah. Their ages ranged from 9-79 years. Of 602, Twenty six, 15 years of age or younger had mean blood lead levels (BLL) of 12.62+3.85 ug/ dl, those older than 15 years had levels of 11.20+3.4 ug /dl (p < 0.05). Males of different age groups showed a statistically significantly higher BLL compared to females (13.25+3.25 and 10.10+2.96 ug/ dl respectively), p < 0.0001. The center of Basrah was divided into 11 main areas; there was a statistically significant difference in BLL among individuals living in different areas, ranging from 7.26+2.81 |jg/ dl to 12.76+3.63 ug/dl. Individuals with higher education and smokers showed higher BLL (12.10+3.54 ug/dl, 13.81+3.57 ug/dl respectively) compared to those of lower education and non-smokers (11.11+3.23 ug/ dl, 10.93+3.26 ug/dl respectively), the differences were statistically significant. The sources of drinking water and frequency and amount of milk consumed/ week did not show a significant correlation with BLL. History of lead exposure (occupational) was statistically significantly associated with BLL (15.3+4.85 ug/ dl) for those exposed to higher concentration of lead compared to others (11.1 2+3.3 ug/dl), p < 0.0001. Amongst females using kohl (25.6%), the mean BLL was significantly higher (13.91+4.42 ug/dl), compared to non-users (9.88+2.68 ug/dl), p < 0.0001. No significant difference was observed among those exposed to paints. As adequate data on BLL in our country do not exist, especially for children, and as the number of children in this study was small, further studies are warranted to recognize the extent and risk factors for lead poisoning in children.

Effects of lead on thyroid functions in lead-exposed workers

Abstract Lead exposure is a common public health problem. Exposure to the metal can cause hematological, gastrointestinal, rheumatological, endocrine, neurological and renal problems in humans. However, effects on the thyroid gland are controversial. We retrospectively investigated thyroid function parameters in 65 adult males who had been occupationally exposed to lead. We then compared the findings with those of 60 male patients who had no history of lead exposure or thyroid abnormalities, who served as the control group. The mean ages of the lead-exposed workers and the controls were 34.3 ± 7.9 and 32.9 ± 6.6 years respectively. Blood lead levels in the lead-exposed workers were significantly higher than in the control group. The lead-exposed workers were assigned to one of three groups according to their blood lead levels, as follows: 40–59 μg/dl, 60–79 μg/dl, or 80 μg/dl and above. Thyroid Stimulating Hormone (TSH) levels in the 80 μg/dl and above group were significantly higher than in either the 40–59 μg/dl group or the 60–79 μg/dl group. However, TSH levels in the 40–59 μg/dl group did not differ significantly from those in the 60–79 μg/dl group. These results suggest that high levels of lead in the blood may affect thyroid physiology. Clinicians should be aware of the potential hazardous effects of lead on the thyroid, especially in patients who have been occupationally exposed to lead.

Feather Lead Concentrations and 207Pb/206Pb Ratios Reveal Lead Exposure History of California Condors (Gymnogyps californianus)

Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only approximately 10% of a bird's annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird's lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2-4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.

Lead poisoning from an Ayurvedic herbal medicine in a patient with chronic kidney disease

A 60-year-old man with a history of diabetes and hypertension was referred to a nephrology clinic for investigation of his elevated serum creatinine level. Physical examination; laboratory investigations, including measurement of whole-blood lead level, body lead burden and urine albumin:creatinine ratio; history of lead exposure and use of herbal medical products; and renal ultrasonography. Stage 3 chronic kidney disease that was probably worsened by consumption of lead in the form of an Ayurvedic herbal remedy. Cessation of the herbal product, followed by lead-chelation therapy with calcium disodium ethylenediaminetetraacetic acid. The patient's whole-body lead burden and blood lead level decreased to acceptable levels and his serum creatinine value was within the normal range at final follow-up.

Plumbemia em trabalhadores da indústria de reciclagem de baterias automotivas da Grande Porto Alegre, RS

A reciclagem de baterias pode contaminar o ar, o solo e a água, não só no lugar de processamento, mas também nas regiões circunvizinhas, sendo que os resíduos permanecem no local mesmo após o término da atividade. No presente artigo descrevemos os resultados da avaliação da plumbemia em 53 operários que trabalhavam com reciclagem de baterias automotivas e em 53 indivíduos sem história de exposição. Os dados obtidos foram comparados e discutidos em relação às normas do Ministério do Trabalho (MT) e da Occupational Safety and Health Administration (OSHA). A plumbemia no sangue do grupo controle foi de 2,44±1,15 µg/dl e, no grupo exposto, de 59,43±28,34 µg/dl, sendo que 79,2% dos indivíduos mostraram níveis acima do valor de referência (até 40 µg/dl). Estudos recentes recomendam estratégias para prevenir a intoxicação com chumbo: identificação, eliminação ou controle da fonte, monitoração da exposição e respectivos danos e um programa de recompra de baterias usadas das por parte da indústria de origem.

Relationship between lead exposure, cognitive function, and drug addiction: Pilot study and research agenda

Lead toxicity has been associated with behavioral handicaps, reading disability, antisocial and hyperactive behavior, juvenile delinquency, and impaired cognition. In addition, preclinical studies suggest an association with drug addiction; e.g., animals treated with lead either pre- or postnatally self-administer opiates at a much higher rate than untreated animals. Iron deficiency further increases the risk of lead toxicity through enhanced absorption of lead in the gastrointestinal tract. Female injection drug users have a high prevalence of iron deficiency, although the question remains as to whether this relationship is either a partial function of high lead exposure or heroin use. Specific aims were to preliminarily determine whether female injection heroin users have high tibial lead concentrations, a marker for cumulative lead exposure, compared with normal reference populations, and whether cognitive deficits potentiated the relationship between lead exposure and frequency of heroin use. Tibial lead concentrations were measured via 109Cd-based K-shell X-ray fluorescence. In 26 female injection heroin users, mean (standard deviation (SD)) tibial lead concentration was 14.5 (6.8) μg/(g bone mineral), which was 1.8 times higher than the tibial lead concentration found among age-adjusted normal community-dwelling women. Interaction effects of tibial lead concentration and selected cognitive functions on frequency with which heroin was used were significant. Further research is warranted to determine whether a history of lead exposure is associated with increased proclivity to drug addiction.

Air Pollution and Heart Rate Variability

Outdoor air pollution and lead exposure can disturb cardiac autonomic function, but the effects of both these exposures together have not been studied. We examined whether higher cumulative lead exposures, as measured by bone lead, modified cross-sectional associations between air pollution and heart rate variability among 384 elderly men from the Normative Aging Study. We used linear regression, controlling for clinical, demographic, and environmental covariates. We found graded, significant reductions in both high-frequency and low-frequency powers of heart rate variability in relation to ozone and sulfate across the quartiles of tibia lead. Interquartile range increases in ozone and sulfate were associated respectively, with 38% decrease (95% confidence interval = -54.6% to -14.9%) and 22% decrease (-40.4% to 1.6%) in high frequency, and 38% decrease (-51.9% to -20.4%) and 12% decrease (-28.6% to 9.3%) in low frequency, in the highest quartile of tibia lead after controlling for potential confounders. We observed similar but weaker effect modification by tibia lead adjusted for education and cumulative traffic (residuals of the regression of tibia lead on education and cumulative traffic). Patella lead modified only the ozone effect on heart rate variability. People with long-term exposure to higher levels of lead may be more sensitive to cardiac autonomic dysfunction on high air pollution days. Efforts to understand how environmental exposures affect the health of an aging population should consider both current levels of pollution and history of lead exposure as susceptibility factors.

Long-term outcome of repeated lead chelation therapy in progressive non-diabetic chronic kidney diseases

Previous research suggest that repeated lead-chelation therapy decelerates progression of renal insufficiency in non-diabetic (non-DM) patients with high-normal body lead burden (BLB). Study findings are limited by relatively short-term follow-up and small sample size. A total of 116 non-DM patients with chronic kidney diseases (serum creatinine level of 1.5-3.9 mg/dl), high-normal BLB (>60 microg and <600 microg) and no lead exposure history were randomly assigned to a chelation or control group in this 4-year clinical trial. For 3 months, the 58 chelation group patients received initial lead-chelation therapy with calcium disodium EDTA, and the 58 control group patients received placebos. During the ensuing 48 months, repeated chelation therapy was administered weekly to chelation group patients unless, on repeated testing, BLB was <60 microg; the control group patients received weekly placebo infusions for 5 weeks at 6-month intervals. Mean change in the glomerular filtration rate (GFR) in the chelation group was -1.8 +/- 8.8 ml/min/1.73 m(2), as compared with -12.7 +/- 8.4 ml/min/1.73 m(2) in the control group (P <0.0001) at study end. Chelation group rates of decline in the GFR was lower than that in the control group, although they had similar decline rates before chelation. At study end, 18 patients, including 15 control group patients, had elevated serum creatinine levels to two times the baseline values. Both Cox and Kaplan-Meier analysis demonstrated repeated chelation therapy was the important determining factor of progression of renal insufficiency. Repeated chelation therapies can, over a four-year period, slow progression of renal insufficiency in non-DM patients with high-normal BLB.

Anaemia and abdominal pain due to occupational lead poisoning

We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure in a battery recycling plant. The diagnosis of poisoning was confirmed by high lead levels in the blood and urine, decreased erythrocyte delta-aminolevulinic acid dehydratase (ALA-D), raised erythrocyte zinc protoporphyrin (ZP), and elevated urinary excretion of porphyrins. Chelation with EDTA resulted in increased urinary lead excretion, gradual improvement of the clinical picture, and progressive normalization of lead biomarkers. The case highlights the importance of occupational anamnesis for the diagnosis of lead poisoning, an uncommon condition which may mimic a variety of internal and surgical diseases. Since antiquity, lead has been extensively mined, produced, and utilized in a variety of industrial settings, such as metallurgy, construction, production of plastics, ceramics, paints and pigments. Lead and its compounds are systemic toxicants, and a wide range of adverse health effects (including haematological, gastrointestinal, neuropsychiatric, cardiovascular, renal, endocrine, and reproductive disorders) has been observed in exposed workers. The general population (particularly children) may also be exposed to toxic lead levels due to air, soil, food and water contamination. Thanks to the improvement of workplace hygienic conditions, the pathological picture of occupational lead poisoning (plumbism, saturnism) has gradually become less serious, at least in the most industrialized countries, and has progressively changed into aspecific, subclinical manifestations. We describe here an unusual case (nowadays) of anaemia and recurrent abdominal pain due to lead poisoning from battery recycling.

Low-level Environmental Exposure to Lead and Progressive Chronic Kidney Diseases

Purpose To determine whether low-normal body lead burden (BLB) accelerates progressive renal insufficiency in nondiabetic patients with chronic kidney diseases (CKD). Methods One hundred eight CKD patients (serum creatinine between 1.5 and 2.9 mg/dL) with low-normal BLB (<80 μg) and no lead exposure history were observed for 24 months. Following the observation, 32 patients with low-normal BLB (≥20 μg and <80 μg) were randomly assigned to chelation and control groups. The chelation group patients were given edetate calcium disodium (EDTA) chelation therapy for 3 months and repeated chelation therapy during the following 24 months to maintain their BLB below 20 μg, while the control group patients underwent placebo therapy. The primary endpoint was an increased serum creatinine level to 1.25 times the baseline value. The secondary endpoint was temporal changes in renal function. Results The primary endpoint occurred in 14 patients in the observation period. Baseline BLB was the important risk factor in determining progressive renal insufficiency. The mean glomerular filtration rate (GFR) change in the chelation group patients was 6.6 ± 10.7 mL/min/1.73m 2, compared with −4.6 ± 4.3 mL/min/1.73m 2 in control group patients ( P <.001) at the end of the intervention period. The mean decrease in GFR per year of chelation group patients was lower than that of control group patients during the repeated chelation period. Conclusion Environmental exposure to lead, even at low level, may accelerate progressive renal insufficiency of nondiabetic patients with CKD.

Environmental exposure to lead and progressive diabetic nephropathy in patients with type II diabetes

Studies indicate that environmental exposure to lead is associated with reduced renal function. Whether lead affects progressive diabetic nephropathy is unclear. Eighty-seven patients with type II diabetes and diabetic nephropathy (serum creatinine of 1.5-3.9 mg/dl) with normal body lead burden and no lead exposure history were observed over a 12-month period. Thirty subjects with high normal body lead burdens (80-600 microg) were randomly assigned to a chelation and control group. For 3 months, the 15 chelation-group patients underwent lead-chelation therapy with calcium disodium ethylenediaminetetraacetic acid weekly until body lead burden fell <60 microg, and the 15 control group subjects received a weekly placebo. During the following 12 months, renal function was regularly assessed at 3-month intervals. The primary outcome was an elevation of serum creatinine to 1.5 times baseline value during the observation period. A secondary outcome was temporal changes in renal function following chelation therapy. Twenty-six patients achieved the primary outcome. Basal blood lead levels and body lead burden were the most important risk factors in predicting progressive diabetic nephropathy. Following chelation, the rates of decline in glomerular filtration rates in the chelation group and the control group, respectively, were 5.0+/-5.7 ml and 11.8+/-7.0 ml/min/year/1.73 m(2) of body surface area (P=0.0084) during follow-up, although both groups had similar rates of progression of renal function during the 12-month observation period. We concluded that low-level environmental lead exposure accelerates progressive diabetic nephropathy and lead-chelation therapy can decrease its rate of progression.

Contrasting effects of age on the plasma/whole blood lead ratio in men and women with a history of lead exposure

We examined the effect of age and sex on the relationship between the concentrations of Pb in blood (Pb-B) and in plasma (Pb-P) in an adult population with a history of lead exposure. Pb-P was determined by inductively coupled plasma mass spectrometry (ICP-MS) and Pb-B by graphite furnace atomic absorption spectrometry (GF AAS). We studied 154 adults (56 men and 98 women) from 18 to 60-year old. Pb-B levels varied from 10.0 to 428.0 μg/L, with a mean of 76 μg/L. Blood lead levels varied from 10.0 to 428.0 μg/L in men (mean, 98.3 μg/L) and from 10.0 to 263.0 μg/L (mean, 62.8 μg/L) in women. Corresponding Pb-Ps were 0.02–2.9 μg/L (mean, 0.66 μg/L) and 0.02–1.5 μg/L (mean, 0.42 μg/L) in men and women, respectively. The relationship between Pb-B and Pb-P was found to be curvilinear ( r=0.757, P<0.001 Spearman's correlation). The two quantities are related by the line y=0.0006 x 1492 ( y=Pb-P, and x=Pb-B). The %Pb-P/Pb-B ratio ranged from 0.03% to 1.85%. A positive association was found between %Pb-P/Pb-B ratio and Pb-B levels. When data were separated by sex, this association was also relevant for men ( y=0.0184 x 0.702) and women ( y=0.0534 x 0.5209) ( y=%Pb-P/Pb-B and x=Pb-B). Moreover, we found an interesting positive correlation between Log (Pb-P/Pb-B) and age for women ( r=0.31, P<0.0001) and a negative correlation for men ( r=−0.164, P=0.07). Taken together, these results suggest contrasting effects of age on the plasma/whole blood lead ratio in men and women with a history of lead exposure. Moreover, sex might play an important role in the metabolism of lead, implying further consideration on the kinetic models constructed of lead toxicity.

Transition of cord blood lead level, 1985–2002, in the Taipei area and its determinants after the cease of leaded gasoline use

Lead has long been of concern for its toxicity, impairment of neurobehavioral and cognitive development, and electrophysiological deficits in children, even at levels less than 10μg/dL. The present study was conducted to elucidate the extent of cord blood lead level decline in the Taipei area from 1985 to 2002 and to explore the factors affecting the cord blood lead level after the cease of leaded gasoline use. In the current study period of 2001–2002, 184 of 1310 newborns delivered in the Taipei Municipal Women and Children Hospital between September 2001 and August 2002 were eligible and randomly selected to participate in this study. Neither of their parents had an occupational lead exposure history. At each delivery, a sample of 5–10mL umbilical cord blood was collected for lead determination by graphite furnace atomic absorption spectrometry. The cord blood lead level of the newborns in the current study period averaged 2.35±1.12μg/dL. Together with the cord blood lead averages of 7.48±2.25 and 3.28±1.52μg/dL obtained from two previous surveys conducted in 1985–1987 and 1990–1992, respectively, the cord blood lead level was significantly decreased (P<0.005). It is estimated that such a reduction in cord blood lead from 7.48 to 2.35μg/dL for each year's cohort of 260,000 newborns in Taiwan might benefit the economics, ranging from US$8.9 billion to US$12.1 billion by improving the worker productivity. For the time period from 1985 to 2002, there were consistent transition patterns among the yearly fluctuations of air lead level, leaded gasoline consumption, lead content in gasoline, estimated lead amount emitted from the consumed leaded gasoline, and average cord blood lead levels of the three respective study periods. Additionally, every 0.1-g/L reduction in lead content in gasoline might lead to a lowering of cord blood lead level by 1.78μg/dL. Furthermore, at low level of around 2μg/dL, a multiple regression analysis demonstrated that economic status was the most influential factor for cord blood lead variation (P=0.0061) while the maternal working month during her pregnancy was retained in the model with borderline effect (P=0.0625). After accounting for the effect of leaded gasoline on the cord blood lead level, future study to differentiate the primary contributors for the low-level cord blood lead variation around 1–2μg/dL is warranted.

Emissões otoacústicas - produto de distorção em indivíduos expostos ao chumbo e ao ruído

Atualmente, as legislações nacionais voltadas à saúde do trabalhador exigem que a audição seja monitorada apenas quando há exposição ocupacional ao ruído, não sendo considerada, assim, a exposição a produtos químicos. Entretanto, na literatura científica, é bastante clara a preocupação sobre os efeitos do chumbo no sistema auditivo, uma vez que foram observados efeitos negativos após a exposição ocupacional a este metal. OBJETIVO: O presente estudo teve como objetivo analisar a amplitude das emissões otoacústicas evocadas por produto de distorção, em indivíduos com histórico de exposição ao chumbo e ruído. FORMA DE ESTUDO: Coorte Transversal. MATERIAL E MÉTODO: Foram avaliados 69 indivíduos subdivididos em 3 grupos: Grupo I (GI): composto por 29 trabalhadores expostos ao chumbo com exposição simultânea ao ruído, em seu ambiente de trabalho; Grupo II (GII): composto por 11 trabalhadores expostos ao ruído ocupacional sem exposição simultânea ou pregressa a outros agentes nocivos à audição; e Grupo III (GIII): composto por 11 indivíduos com audição normal, sem histórico de exposição ao ruído ocupacional ou de outros fatores de risco para a ocorrência de perda auditiva. RESULTADO: Os resultados obtidos não evidenciaram o efeito tóxico do chumbo nos resultados das emissões otoacústicas, visto que as menores amplitudes das EOEPD foram observadas no grupo exposto somente ao ruído, mesmo considerando que os indivíduos expostos ao chumbo com exposição simultânea ao ruído apresentavam longo período de exposição a este metal bem como ampla variação do nível de chumbo sérico.