High Lead Exposure Associated With Higher Blood Pressure in Haiti: a Warning Sign for Low-Income Countries.

Cardiovascular disease is the leading cause of death in lower-income countries including Haiti. Environmental lead exposure is associated with high blood pressure and cardiovascular mortality in high-income countries but has not been systematically measured and evaluated as a potential modifiable cardiovascular risk factor in lower-income countries where 6.5 billion people reside. We hypothesized lead exposure is high in urban Haiti and associated with higher blood pressure levels. Blood lead levels were measured in 2504 participants ≥18 years enrolled in a longitudinal population-based cohort study in Port-au-Prince. Lead screening was conducted using LeadCare II (detection limit ≥3.3 µg/dL). Levels below detection were imputed by dividing the level of detection by √2. Associations between lead (quartiles) and systolic blood pressure and diastolic blood pressure were assessed, adjusting for age, sex, obesity, smoking, alcohol, physical activity, income, and antihypertensive medication use. The median age of participants was 40 years and 60.1% were female. The geometric mean blood lead level was 4.73µg/dL, 71.1% had a detectable lead level and 42.3% had a blood lead level ≥5 µg/dL. After multivariable adjustment, lead levels in quartile four (≥6.5 µg/dL) compared with quartile 1 (<3.4 µg/dL) were associated with 2.42 mm Hg (95% CI, 0.36-4.49) higher systolic blood pressure and 1.96 mm Hg (95% CI, 0.56-3.37) higher diastolic blood pressure. In conclusion, widespread environmental lead exposure is evident in urban Haiti, with higher lead levels associated with higher systolic and diastolic blood pressure. Lead is a current and potentially modifiable pollutant in lower-income countries that warrants urgent public health remediation. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03892265.

Secondhand Tobacco Smoke Exposure and Neuromotor Function in Rural Children.

OBJECTIVE: To investigate the relationship between secondhand tobacco smoke (SHS) exposure and neuromotor function in children. STUDY DESIGN: We studied 404 children aged 7-9 years who were exposed to SHS and other environmental neurotoxicants. Parents reported smoking habits, and serum cotinine levels were measured in children to determine SHS exposure. The Halstead-Reitan Finger Oscillation Test, Purdue Grooved Pegboard Test-Kiddie version, and Bruininks-Oseretsky Test of Motor Proficiency 2-Short Form were used to assess neuromotor function. Multivariable regression models that accounted for potential confounders were used to evaluate the associations. RESULTS: Approximately 50% of the children were exposed to SHS based on serum cotinine measures. Exposure to SHS was significantly associated with motor impairment in children, including diminished visuomotor coordination (P = .01), fine motor integration (P = .01), balance (P = .02), and strength (P = .04) after adjusting for exposures to lead and manganese, age, sex, body mass index, measures of parental cognitive abilities, parental education, and quality of home environment. CONCLUSION: SHS is a neurotoxicant that may be associated with impaired childhood neuromotor function.

Association of arsenic and metals with concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D among adolescents in Torreón, Mexico.

BACKGROUND: Limited data suggest that lead (Pb), cadmium (Cd), and uranium (U) may disrupt vitamin D metabolism and inhibit production of 1,25-dihydroxyvitamin D [1,25(OH)2D], the active vitamin D metabolite, from 25-hydroxyvitamin D [25(OH)D] in the kidney. OBJECTIVES: We evaluated the association between blood lead (BPb) and urine arsenic (As), Cd, molybdenum (Mo), thallium (Tl), and U with markers of vitamin D metabolism [25(OH)D and 1,25(OH)2D]. METHODS: We conducted a cross-sectional study of 512 adolescents in Torreón, a town in Mexico with a Pb smelter near residential areas. BPb was measured using atomic absorption spectrometry. Urine As, Cd, Mo, Tl, and U were measured using inductively coupled plasma mass spectrometry. Serum 25(OH)D and 1,25(OH)2D were measured using a chemiluminescent immunoassay and a radioimmunoassay, respectively. Multivariable linear models with vitamin D markers as the outcome were used to estimate associations of BPb and creatinine-corrected urine As and metal concentrations with serum vitamin D concentrations, controlling for age, sex, adiposity, smoking, socioeconomic status, and time outdoors. RESULTS: Serum 25(OH)D was positively associated with urine Mo and Tl [1.5 (95% CI: 0.4, 2.6) and 1.2 (95% CI: 0.3, 2.1) ng/mL higher with a doubling of exposure, respectively]. Serum 1,25(OH)2D was positively associated with urine As and U [3.4 (95% CI: 0.9, 5.9) and 2.2 (95% CI: 0.7, 3.7) pg/mL higher, respectively], with little change in associations after additional adjustment for serum 25(OH)D. Pb and Cd were not associated with 25(OH)D or 1,25(OH)2D concentrations. CONCLUSIONS: Overall, our findings did not support a negative effect of As or metal exposures on serum 1,25(OH)2D concentrations. Additional research is needed to confirm positive associations between serum 1,25(OH)2D and urine U and As concentrations and to clarify potential underlying mechanisms.

Spatial clustering of toxic trace elements in adolescents around the Torreón, Mexico lead-zinc smelter.

High blood lead (BPb) levels in children and elevated soil and dust arsenic, cadmium, and lead were previously found in Torreón, northern Mexico, host to the world's fourth largest lead-zinc metal smelter. The objectives of this study were to determine spatial distributions of adolescents with higher BPb and creatinine-corrected urine total arsenic, cadmium, molybdenum, thallium, and uranium around the smelter. Cross-sectional study of 512 male and female subjects 12-15 years of age was conducted. We measured BPb by graphite furnace atomic absorption spectrometry and urine trace elements by inductively coupled plasma-mass spectrometry, with dynamic reaction cell mode for arsenic. We constructed multiple regression models including sociodemographic variables and adjusted for subject residence spatial correlation with spatial lag or error terms. We applied local indicators of spatial association statistics to model residuals to identify hot spots of significant spatial clusters of subjects with higher trace elements. We found spatial clusters of subjects with elevated BPb (range 3.6-14.7 µg/dl) and urine cadmium (0.18-1.14 µg/g creatinine) adjacent to and downwind of the smelter and elevated urine thallium (0.28-0.93 µg/g creatinine) and uranium (0.07-0.13 µg/g creatinine) near ore transport routes, former waste, and industrial discharge sites. The conclusion derived from this study was that spatial clustering of adolescents with high BPb and urine cadmium adjacent to and downwind of the smelter and residual waste pile, areas identified over a decade ago with high lead and cadmium in soil and dust, suggests that past and/or present plant operations continue to present health risks to children in those neighborhoods.

Assessment of prenatal mercury exposure in a predominately Caribbean immigrant community in Brooklyn, NY.

Prenatal mercury exposure and its fetotoxic effects may be of particular concern in urban immigrant communities as a result of possible contributing cultural factors. The most common source of exposure in these communities is ingestion of fish and shellfish contaminated with methylmercury. Other sources of exposure may occur in ritualistic practices associated with Hispanic and Caribbean-based religions. This study 1) assessed total mercury levels in both random urine specimens from pregnant women, and in cord blood; and 2) examined environmental sources of exposure from a convenience sample in a predominantly Caribbean immigrant population in Brooklyn, New York. A questionnaire designed in collaboration with health professionals from the Caribbean community assessed the frequency of fish consumption, ritualistic practices, occupational exposures, and use of dental amalgams and mercury-containing skin and household products. The geometric mean for total mercury in cord blood was 2.14 µg L(-1) (95%CI: 1.76-2.60) (n = 78), and 0.45 µg L(-1) (95%CI: 0.37-0.55) (n = 183) in maternal urine corrected for creatinine (µg g(-1)). Sixteen percent of cord blood mercury levels exceeded the estimated equivalent of U.S. Environmental Protection Agency's Reference Dose (5.8 µg L(-1) blood). Predictors of cord blood mercury included maternal fish consumption and foreign birth of the mother. Predictors of urine mercury included foreign birth of the mother, number of dental amalgams, and special product use. There were no reports of mercury use in ritualistic practices or in cosmetics; however some women reported use of religious medals and charms. This study characterized risk factors for mercury exposure in a sample of urban, predominantly Caribbean-born blacks. Findings may help target interventions in this population, which might include appropriate fish selection and consumption frequency during pregnancy, and safe handling of mercury-containing products in the home.

Mercury exposure in young children living in New York City.

Residential exposure to vapor from current or previous cultural use of mercury could harm children living in rental (apartment) homes. That concern prompted the following agencies to conduct a study to assess pediatric mercury exposure in New York City communities by measuring urine mercury levels: New York City Department of Health and Mental Hygiene's (NYCDOHMH) Bureau of Environmental Surveillance and Policy, New York State Department of Health/Center for Environmental Health (NYSDOHCEH), Wadsworth Center's Biomonitoring Program/Trace Elements Laboratory (WC-TEL), and Centers for Disease Control and Prevention (CDC). A previous study indicated that people could obtain mercury for ritualistic use from botanicas located in Brooklyn, Manhattan, and the Bronx. Working closely with local community partners, we concentrated our recruiting efforts through health clinics located in potentially affected neighborhoods. We developed posters to advertise the study, conducted active outreach through local partners, and, as compensation for participation in the study, we offered a food gift certificate redeemable at a local grocer. We collected 460 urine specimens and analyzed them for total mercury. Overall, geometric mean urine total mercury was 0.31 microg mercury/l urine. One sample was 24 microg mercury/l urine, which exceeded the (20 microg mercury/l urine) NYSDOH Heavy Metal Registry reporting threshold for urine mercury exposure. Geometric mean urine mercury levels were uniformly low and did not differ by neighborhood or with any clinical significance by children's ethnicity. Few parents reported the presence of mercury at home, in a charm, or other item (e.g., skin-lightening creams and soaps), and we found no association between these potential sources of exposure and a child's urinary mercury levels. All pediatric mercury levels measured in this study were well below a level considered to be of medical concern. This study found neither self-reported nor measured evidence of significant mercury use or exposure among participating children. Because some participants were aware of the possibility that they could acquire and use mercury for cultural or ritualistic purposes, community education about the health hazards of mercury should continue.

Blood lead levels in children aged 5-9 years living in Cartagena, Colombia.

During June-August 2004, blood lead (BPb) levels and various hematological parameters were evaluated in children aged 5-9 years old at ten primary schools located in eight neighborhoods in Cartagena, Colombia. The schools selected for this study are attended mainly by children from families of low income. A total of 189 subjects participated in the survey. The arithmetic mean+/-standard error BPb level was 5.49+/-0.23 microg/dL (range<1.0-21.0 microg/dL). The geometric mean was 4.74 microg/dL (95% CI: 4.29-5.18). A proportion of the children (7.4%) had BPb levels above the US Centers for Disease Control and Prevention's threshold of concern (10 microg Pb/dL). BPb levels were correlated weakly, but significantly and positively, with red blood cell count (RBC), and negatively with child body size, age, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH). BPb levels did not differ significantly between boys and girls but significant differences were observed between neighborhoods (P<0.001). Activities such as metal melting-related processes and fishing net sinker production are the main sources of Pb exposure in Cartagena.

A critical review of biomarkers used for monitoring human exposure to lead: advantages, limitations and future needs

A concentração de chumbo (Pb) no sangue total (Pb-B) vem sendo comumente utilizada para monitorar a exposição a este elemento químico. Entretanto, a dificuldade em avaliar a natureza exata da exposição ao Pb é dependente não só de problemas inerentes a metodologias analíticas inapropriadas, bem como da toxicocinética complexa do Pb em compartimentos de nosso corpo. Se quisermos diferenciar mais efetivamente entre o Pb que está estocado no corpo por anos daquele proveniente de uma exposição recente, deverão ser obtidas informações pela análise de outros biomarcadores de exposição. Entretanto, nenhum dos biomarcadores de dose interna para Pb é aceito pela comunidade científica como substituto ao Pb-B. O foco desta revisão está nas limitações de biomarcadores de exposição ao Pb e nas necessidades para melhorar a exatidão nas determinações. Procuramos apresentar somente os protocolos analíticos em uso corrente e tentamos avaliar a infuência de variáveis de confusão nos níveis de Pb-B. Finalmente, fizemos uma discussão sobre a interpretação dos dados de Pb-B com respeito a fontes de exposição, sejam elas endógenas e exógenas, recente ou passada, bem como a importância das determinações de Pb no cabelo, unhas, saliva, ossos, sangue (plasma e sangue total), urina, fezes e dente decíduo.

A critical review of biomarkers used for monitoring human exposure to lead: advantages, limitations, and future needs.

Lead concentration in whole blood (BPb) is the primary biomarker used to monitor exposure to this metallic element. The U.S. Centers for Disease Control and Prevention and the World Health Organization define a BPb of 10 microg/dL (0.48 micromol/L) as the threshold of concern in young children. However, recent studies have reported the possibility of adverse health effects, including intellectual impairment in young children, at BPb levels < 10 microg/dL, suggesting that there is no safe level of exposure. It appears impossible to differentiate between low-level chronic Pb exposure and a high-level short Pb exposure based on a single BPb measurement; therefore, serial BPb measurements offer a better estimation of possible health outcomes. The difficulty in assessing the exact nature of Pb exposure is dependent not so much on problems with current analytical methodologies, but rather on the complex toxicokinetics of Pb within various body compartments (i.e., cycling of Pb between bone, blood, and soft tissues). If we are to differentiate more effectively between Pb stored in the body for years and Pb from recent exposure, information on other biomarkers of exposure may be needed. None of the current biomarkers of internal Pb dose have yet been accepted by the scientific community as a reliable substitute for a BPb measurement. This review focuses on the limitations of biomarkers of Pb exposure and the need to improve the accuracy of their measurement. We present here only the traditional analytical protocols in current use, and we attempt to assess the influence of confounding variables on BPb levels. Finally, we discuss the interpretation of BPb data with respect to both external and endogenous Pb exposure, past or recent exposure, as well as the significance of Pb determinations in human specimens including hair, nails, saliva, bone, blood (plasma, whole blood), urine, feces, and exfoliated teeth.