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.

Association of plasma lead, cadmium, and selenium levels with hearing loss in adults: NHANES 2011-2012

To determine the association between hearing loss and environmental lead, cadmium, and selenium exposure, a total of 1503 American adults from National Health and Nutrition Examination Survey (NHANES) (2011∼2012) were assessed. The average of 4 audiometric frequencies (0.5, 1, 2, and 4 kHz) was used to identify speech-frequency hearing loss (SFHL), while the average of 3 audiometric frequencies (3, 4, and 6 kHz) was used to identify high-frequency hearing loss (HFHL). HFHL adjusted Odds ratios (ORs) determined by comparing the highest and lowest blood lead and cadmium quartiles were 1.98 (95%CI: 1.27, 3.10) and 1.81 (95%CI: 1.13, 2.90), respectively. SFHL was significant associated with blood cadmium with the OR = 2.42 for the highest quartile. When further stratified by age, this association appeared to be limited to adults aged 35-52 years. After stratified by gender, except for lead and cadmium, we observed that blood selenium showed a dose-dependent association with SFHL in men. In women, only cadmium showed a dose-dependent association with speech and high frequency hearing loss. Hearing loss was positively associated with blood levels of lead and cadmium. Additionally, our study provided novel evidence suggesting that excessive selenium supplement would increase SFHL risk in men.

An investigation of chronic exposure of lead to the pregnant laboratory animal and its effects on their offspring: Autism investigation to the laboratory animal model in Bangladesh

Lead poisoning is a continuing crisis impacting learning, neurological and behavioral development in children. This study investigated an important outcome from the environmental lead contamination which cause retardation of infant’s brain development. A total of 30 Swiss albino mice of both sexes were used in this study and divide into three groups consisting 6 female and 4 male in each group. Two groups of mice were given lead treated drinking (30 ppm and 230 ppm respectively) and rat pellets ad libitum and the control mice were supplied normal drinking water and rat pellets ad libitum. At 20-21th days of pregnancy lead-induced female mouse gave birth to a litter of 5-6 pups; whereas, control mouse gave birth to 10-13 pups at a time. Both lead-induced and controlled offspring were found normal; however, some lead-induced offspring were found comparatively smaller than the control one. Autism spectrum disorder behavioral diagnostic tools were used to explore the level of autism, if any. The anxiety assessment marble burying investigation did not reveal any significant differences among the group’s mice. Three chambered social interaction analysis found no significant differences among the mice. Blood serum level of lead for controlled mice were found 0.333mg/dL, whereas, 30 ppm and 230 ppm lead-induced born mice were found 3.833mg/dL and 9.666mg/dL respectively. This study suggested that a genetic predisposition pair with exposure to environmental toxicants play important role in the causes of autism spectrum disorder. Lead is not the pivotal factor of autism development in new born offspring in mice

An Intercategorical Ecology of Lead Exposure: Complex Environmental Health Vulnerabilities in the Flint Water Crisis

In 2014, city and state officials channeled toxic water into Flint, Michigan and its unevenly distributed and corroding lead service lines (LSLs). The resulting Flint water crisis is a tragic example of environmental racism against a majority Black city and enduring racial and spatial disparities in environmental lead exposures in the United States. Important questions remain about how race intersected with other established environmental health vulnerabilities of gender and single-parent family structure to create unequal toxic exposures within Flint. We address this question with (1) an “intercategorical ecology” framework that extends the “racial ecology” lens into the complex spatial and demographic dimensions of environmental health vulnerabilities and (2) a multivariate analysis using block-level data from the 2010 U.S. decennial census and a key dataset estimating the LSL connections for 56,038 land parcels in Flint. We found that blocks exposed to LSLs had, on average, higher concentrations of single-parent white, Black, and Latinx families. However, logistic regression results indicate that the likelihood of block exposure to LSLs was most consistently and positively associated with the percentage of single-father Black and single-mother Latina families, net of other racialized and gendered single-parent family structures, socioeconomic status, and the spatial concentration of LSL exposure.