Loss of cognitive function in Mexican children due to lead exposure and the associated economic costs.

BACKGROUND: Lead exposure reduces the cognitive development and future economic prospects of children. While previous studies in high-income settings have explored productivity losses associated with lead exposure, limited research has focused on low and middle-income countries like Mexico. OBJECTIVES: This study aims to provide a comprehensive assessment of the economic implications of lead exposure on Mexican children using, for the first time, nationally representative Blood Lead Levels (BLLs) measurements in children aged 1-4, specifically focusing on the costs of forgone lifetime income due to cognitive losses. METHODS: BLLs of children aged 1-4 were extracted from the 2018-2019 National Health and Nutrition Survey (ENSANUT). Estimations of cognitive losses were derived from a log-linear relationship between BLLs and IQ loss. Lost lifetime economic productivity per child was calculated, assuming a 2% reduction in lifetime potential productivity for each IQ point lost due to lead exposure, based on previous literature (Attina and Trasande, 2013; Larsen and Sánchez-Triana, 2023). Productivity data were obtained from representative sources for Mexico. RESULTS: The estimated economic loss amounted to US $33.02 billion, equivalent to 2.76% of Mexico's Gross Domestic Product (GDP) in 2019 (calculated for a 1-year cohort). On a national scale, the long-term loss of cognition for children 1-4 years old is 4.14 IQ points per child due to lead exposure, with significant variability across States (range: 3.26 to 5.26). Lead-poisoned children (≥5 µg/dL) suffered an average loss of 6.42 IQ points (range: 0 to 6.97). In terms of economic impact, some States like Chiapas experienced losses of 7.08% of its GDP, while others had losses as low as 0.67%. Intriguingly, states with lower Human Development Index (HDIs) exhibited relatively higher economic losses despite lower average blood lead levels. DISCUSSION: The heterogeneous impact of lead exposure across Mexican states underscores the necessity for tailored regional policies. These findings emphasize the urgency for targeted interventions and informed policy measures to mitigate the socioeconomic consequences of lead exposure on Mexican children.

Contribución de diversas fuentes de exposición a la concentración de plomo en sangre en población infantil mexicana, Ensanut 2022.

OBJETIVO: Analizar la asociación entre fuentes de exposición al plomo (FEPb) y la concentración en sangre capilar (PbS) en menores de 1 a 4 años de edad a nivel nacional y regional, así como cuantificar la contribución relativa de las distintas FEPb. Material y métodos. Se utilizaron datos de la Encuesta Nacional de Salud y Nutrición (Ensanut 2022). Las FEPb consideradas fueron uso de loza de barro vidriada con plomo (LBVPb), residencia cercana a sitios contaminados y exposición paraocupacional. Se estimaron prevalencias de intoxicación (PbS ≥ 5.0 mg/dL) y medias geométricas de PbS. Se utilizaron modelos de regresión para PbS (escala logarítmica) y la descomposición Shapley-Owen de R2 para evaluar la contribución relativa de cada FEPb. RESULTADOS: Las FEPb estudiadas explican el 6% de la variabilidad de PbS a nivel nacional; de este, el 87.3% lo explica el uso de LBVPb, el 4.2% otras FEPb ambiental y 1.3% FEPb paraocupacionales. La contribución relativa del uso de LBVPb varía entre regiones, desde 38.1 a 76.8%. Algunas regiones destacan la FEPb ambiental, pero no paraocupacional. CONCLUSIONES: Los resultados confirman que el uso de LBVPb es la principal fuente de exposición reportada y sugieren que la población no identifica las principales FEPb documentadas hasta ahora.

Analysis of the burden of disease attributable to environmental risk factors in Mexico in the 1990-2021 period. Identification of advances, lags and emergencies.

BACKGROUND: It is estimated that environmental risk factors (ERF) were responsible for nine million deaths worldwide in 2019. OBJECTIVE: Using data from the Global Burden of Disease study, indicators of health loss associated with exposure to ERF in Mexico were analyzed. MATERIAL AND METHODS: Absolute numbers and population percentages of deaths and disability-adjusted life years (DALY) lost attributed to selected ERFs were analyzed at the national and state level and by sex, as well as age-standardized trends from 1990 to 2021. RESULTS: In 2021, ambient particulate matter pollution showed the highest mortality and DALYs lost attributed to selected ERFs (42.2 and 38.1% respectively), followed by lead exposure (20.6 and 13.4%) and low temperature (19.8 and 12.3%). Both indicators have decreased for all selected ERAs by different magnitudes between 1991 and 2021, except for high temperature. CONCLUSIONS: Despite decreases in the last 32 years, outdoor environment particulate matter showed the highest mortality and DALYs lost, followed by lead exposure. It is essential to strengthen air quality and lead exposure policies in Mexico.

ANTECEDENTES: Se estima que los factores de riesgo ambientales (FRA) fueron responsables en 2019 de nueve millones de muertes en el mundo. OBJETIVO: A partir de datos del estudio Global Burden of Disease, se analizaron indicadores de pérdida de salud asociada a la exposición a FRA en México. MATERIAL Y MÉTODOS: Se analizaron números absolutos y porcentajes poblacionales de muertes y años de vida saludable (AVISA) perdidos según sexo atribuidos a FRA seleccionados en los ámbitos nacional y estatal, así como las tendencias estandarizadas por edad de 1990 a 2021. RESULTADOS: En 2021, la contaminación por material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos por los FRA seleccionados (42.2 y 38.1 %, respectivamente), seguida de la exposición a plomo (20.6 y 13.4 %) y temperatura baja (19.8 y 12.3 %). Ambos indicadores han disminuido en todos los FRA seleccionados, en magnitudes diferentes entre 1991 y 2021, excepto la temperatura alta. CONCLUSIONES: A pesar de las disminuciones en los últimos 32 años, el material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos, seguido de la exposición a plomo. Es fundamental fortalecer las políticas de calidad del aire y exposición a plomo en México.

Prenatal Arsenic Exposure on DNA Methylation of C18ORF8 and ADAMTS9 Genes of Newborns from the POSGRAD Birth Cohort Study.

Exposure to arsenic (As) is a public health problem associated with cancer (skin and colon) and it has been reported that epigenetic changes may be a potential mechanism of As carcinogenesis. It is pertinent to evaluate this process in genes that have been associated with cancer, such as ADAMTS9 and C18ORF8. Gestation and delivery data were obtained from the POSGRAD study. Exposure to As was measured in urine during pregnancy. Gene methylation was performed by sodium bisulfite sequencing; 26 CpG sites for the C18ORF8 gene and 21 for ADAMTS9 were analyzed. These sites are located on the CpG islands near the start of transcription. Sociodemographic characteristics were obtained by a questionnaire. The statistical analysis was performed using multiple linear regression models adjusted for potential confounders. Newborns with an As exposure above 49.4 µg g-1 showed a decrease of 0.21% on the methylation rate in the sites CpG15, CpG19, and CpG21 of the C18ORF8 gene (adjusted ß = -0.21, p-value = 0.02). No statistically significant association was found between prenatal exposure to As and methylation of the ADAMTS9 gene. Prenatal exposure to As was associated with decreased DNA methylation at the CpG15, CpG19, and CpG21 sites of the C18ORF8 gene. These sites can provide information to elucidate epigenetic mechanisms associated with prenatal exposure to As and cancer.

Continuous vestibular implant stimulation partially restores eye-stabilizing reflexes.

BACKGROUNDBilateral loss of vestibular (inner ear inertial) sensation causes chronically blurred vision during head movement, postural instability, and increased fall risk. Individuals who fail to compensate despite rehabilitation therapy have no adequate treatment options. Analogous to hearing restoration via cochlear implants, prosthetic electrical stimulation of vestibular nerve branches to encode head motion has garnered interest as a potential treatment, but prior studies in humans have not included continuous long-term stimulation or 3D binocular vestibulo-ocular reflex (VOR) oculography, without which one cannot determine whether an implant selectively stimulates the implanted ear's 3 semicircular canals.METHODSWe report binocular 3D VOR responses of 4 human subjects with ototoxic bilateral vestibular loss unilaterally implanted with a Labyrinth Devices Multichannel Vestibular Implant System vestibular implant, which provides continuous, long-term, motion-modulated prosthetic stimulation via electrodes in 3 semicircular canals.RESULTSInitiation of prosthetic stimulation evoked nystagmus that decayed within 30 minutes. Stimulation targeting 1 canal produced 3D VOR responses approximately aligned with that canal's anatomic axis. Targeting multiple canals yielded responses aligned with a vector sum of individual responses. Over 350-812 days of continuous 24 h/d use, modulated electrical stimulation produced stable VOR responses that grew with stimulus intensity and aligned approximately with any specified 3D head rotation axis.CONCLUSIONThese results demonstrate that a vestibular implant can selectively, continuously, and chronically provide artificial sensory input to all 3 implanted semicircular canals in individuals disabled by bilateral vestibular loss, driving reflexive VOR eye movements that approximately align in 3D with the head motion axis encoded by the implant.TRIAL REGISTRATIONClinicalTrials.gov: NCT02725463.FUNDINGNIH/National Institute on Deafness and Other Communication Disorders: R01DC013536 and 2T32DC000023; Labyrinth Devices, LLC; and Med-El GmbH.

Indoor Radon Gas (222Rn) Levels in Homes in Aldama, Chihuahua, Mexico and the Risk of Lung Cancer.

Radon (222Rn) is an odorless and tasteless gas that is known to cause lung cancer. The objective of this research was to quantify the levels of exposure to radon among people living in an environment rich in uranium (U). Radon concentrations were measured for 3 days in 12 homes in Aldama, Mexico. Homeowners agreed to participate in the study; hence, the sample was non-probabilistic. Radon was measured with a portable AlphaGuard Radon Monitor (Genicron Instruments GmbH), which was placed in a bedroom of each home at a height of 0.74 m. Gas levels were registered in Becquerels (Bq m−3), with readings taken every 10 min along with readings of ambient temperature (AT), air pressure (AP), and relative humidity (RH). We found that radon gas levels in Aldama exceed the maximum permissible limits (USA: 148 Bq m−3). Levels were higher at night, and were above the maximum permissible level recommended by the International Atomic Energy Agency of the United Nations (<200 Bq m−3). Most residents in the area have family histories of lung problems, but it was difficult to establish a strong correlation between 222Rn and lung cancer. Federal, state, and municipal governments should take stronger action to reduce the effects of radon gas on communities.

Análisis de la carga de enfermedad atribuible a los factores de riesgo ambientales en México en el período 1990-2021. Identificación de avances, rezagos y emergencias / Analysis of the burden of disease attributable to environmental risk factors in Mexico in the 1990-2021 period. Identification of advances, lags and emergencies

Resumen Antecedentes: Se estima que los factores de riesgo ambientales (FRA) fueron responsables en 2019 de nueve millones de muertes en el mundo. Objetivo: A partir de datos del estudio Global Burden of Disease, se analizaron indicadores de pérdida de salud asociada a la exposición a FRA en México. Material y métodos: Se analizaron números absolutos y porcentajes poblacionales de muertes y años de vida saludable (AVISA) perdidos según sexo atribuidos a FRA seleccionados en los ámbitos nacional y estatal, así como las tendencias estandarizadas por edad de 1990 a 2021. Resultados: En 2021, la contaminación por material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos por los FRA seleccionados (42.2 y 38.1 %, respectivamente), seguida de la exposición a plomo (20.6 y 13.4 %) y temperatura baja (19.8 y 12.3 %). Ambos indicadores han disminuido en todos los FRA seleccionados, en magnitudes diferentes entre 1991 y 2021, excepto la temperatura alta. Conclusiones: A pesar de las disminuciones en los últimos 32 años, el material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos, seguido de la exposición a plomo. Es fundamental fortalecer las políticas de calidad del aire y exposición a plomo en México.

Abstract Background: It is estimated that environmental risk factors (ERF) were responsible for nine million deaths worldwide in 2019. Objective: Using data from the Global Burden of Disease study, indicators of health loss associated with exposure to ERF in Mexico were analyzed. Material and methods: Absolute numbers and population percentages of deaths and disability-adjusted life years (DALY) lost attributed to selected ERFs were analyzed at the national and state level and by sex, as well as age-standardized trends from 1990 to 2021. Results: In 2021, ambient particulate matter pollution showed the highest mortality and DALYs lost attributed to selected ERFs (42.2 and 38.1% respectively), followed by lead exposure (20.6 and 13.4%) and low temperature (19.8 and 12.3%). Both indicators have decreased for all selected ERAs by different magnitudes between 1991 and 2021, except for high temperature. Conclusions: Despite decreases in the last 32 years, outdoor environment particulate matter showed the highest mortality and DALYs lost, followed by lead exposure. It is essential to strengthen air quality and lead exposure policies in Mexico.

The video ocular counter-roll (vOCR): a clinical test to detect loss of otolith-ocular function.

CONCLUSION: vOCR can detect loss of otolith-ocular function without specifying the side of vestibular loss. Since vOCR is measured with a simple head tilt maneuver, it can be potentially used as a bedside clinical test in combination with video head impulse test. OBJECTIVE: Video-oculography (VOG) goggles are being integrated into the bedside assessment of patients with vestibular disorders. Lacking, however, is a method to evaluate otolith function. This study validated a VOG test for loss of otolith function. METHODS: VOG was used to measure ocular counter-roll (vOCR) in 12 healthy controls, 14 patients with unilateral vestibular loss (UVL), and six patients with bilateral vestibular loss (BVL) with a static lateral head tilt of 30°. The results were compared with vestibular evoked myogenic potentials (VEMP), a widely-used laboratory test of otolith function. RESULTS: The average vOCR for healthy controls (4.6°) was significantly different from UVL (2.7°) and BVL (1.6°) patients (p < 0.0001). The vOCR and VEMP measurements were correlated across subjects, especially the click and tap oVEMPs (click oVEMP R = 0.45, tap oVEMP R = 0.51; p < 0.0003). The receiver operator characteristic (ROC) analysis showed that vOCR and VEMPs detected loss of otolith function equally well. The best threshold for vOCR to detect vestibular loss was at 3°. The vOCR values from the side of vestibular loss and the healthy side were not different in UVL patients (2.53° vs 2.8°; p = 0.59).

Treatment of Menière's Disease.

OPINION STATEMENT: Diagnosis of Menière's disease is made with a characteristic patient history, including discrete episodes of vertigo lasting 20 min or longer, accompanied by sensorineural hearing loss, which is typically low frequency at first, aural fullness, and tinnitus. Workup includes audiometry, a contrast enhanced MRI of the internal auditory canals, and exclusion of other diseases that can produce similar symptoms, like otosyphilis, autoimmune inner ear disease, perilymphatic fistula, superior semicircular canal syndrome, Lyme disease, multiple sclerosis, vestibular paroxysmia, and temporal bone tumors. A history of migraine should be sought as well because of a high rate of co-occurrence (Rauch, Otolaryngol Clin North Am 43:1011-1017, 2010). Treatment begins with conservative measures, including low salt diet, avoidance of stress and caffeine, and sleep hygiene. Medical therapy with a diuretic is the usual next step. If that fails to control symptoms, then the options of intratympanic (IT) steroids and betahistine are discussed. Next tier treatments include the Meniett device and endolymphatic sac surgery, but the efficacy of both is controversial. If the above measures fail to provide symptomatic control of vertigo, then ablative therapies like intratympanic gentamicin are considered. Rarely, vestibular nerve section or labyrinthectomy is considered for a patient with severe symptoms who does not show a reduction in vestibular function with gentamicin. Benzodiazepines and anti-emetics are used for symptomatic control during vertigo episodes. Rehabilitative options for unilateral vestibular weakness include physical therapy and for unilateral hearing loss include conventional hearing aids, contralateral routing of sound (CROS) and osseointegrated hearing aids.

Association Between Visuospatial Ability and Vestibular Function in the Baltimore Longitudinal Study of Aging.

OBJECTIVES: To investigate the relationship between vestibular loss associated with aging and age-related decline in visuospatial function. DESIGN: Cross-sectional analysis within a prospective cohort study. SETTING: Baltimore Longitudinal Study of Aging (BLSA). PARTICIPANTS: Community-dwelling BLSA participants with a mean age of 72 (range 26-91) (N = 183). MEASUREMENTS: Vestibular function was measured using vestibular-evoked myogenic potentials. Visuospatial cognitive tests included Card Rotations, Purdue Pegboard, Benton Visual Retention Test, and Trail-Making Test Parts A and B. Tests of executive function, memory, and attention were also considered. RESULTS: Participants underwent vestibular and cognitive function testing. In multiple linear regression analyses, poorer vestibular function was associated with poorer performance on Card Rotations (P = .001), Purdue Pegboard (P = .005), Benton Visual Retention Test (P = 0.008), and Trail-Making Test Part B (P = .04). Performance on tests of executive function and verbal memory were not significantly associated with vestibular function. Exploratory factor analyses in a subgroup of participants who underwent all cognitive tests identified three latent cognitive abilities: visuospatial ability, verbal memory, and working memory and attention. Vestibular loss was significantly associated with lower visuospatial and working memory and attention factor scores. CONCLUSION: Significant consistent associations between vestibular function and tests of visuospatial ability were observed in a sample of community-dwelling adults. Impairment in visuospatial skills is often one of the first signs of dementia and Alzheimer's disease. Further longitudinal studies are needed to evaluate whether the relationship between vestibular function and visuospatial ability is causal.

A novel method of 3D image analysis of high-resolution cone beam CT and multi slice CT for the detection of semicircular canal dehiscence.

HYPOTHESIS: We investigated if current-generation computed tomographic (CT) scanners have the resolution required to objectively detect bone structure defects as small as 0.1 mm. In addition, we propose that our method is able to predict a possible dehiscence in a semicircular canal. BACKGROUND: In semicircular canal dehiscence (SCD), the bone overlying the superior canal (SC) is partially absent, causing vertigo, autophony, hyperacusis or hearing loss. Diagnosis of SCD is typically based on multi-slice computed tomography (MSCT) images combined with the consideration of clinical signs and symptoms. Recent studies have shown that MSCT tends to overestimate the size of dehiscences and may skew the diagnosis towards dehiscence when a thin bone layer remains. Evaluations of CT scans for clinical application are typically observer based. METHODS: We developed a method of objectively evaluating the resolution of CT scanners. We did this for 2 types of computed tomography: MSCT, and cone beam computed tomography (CBCT), which have been reported to have a higher resolution for temporal bone scans. For the evaluation and comparison of image accuracy between different CT scanners and protocols, we built a bone cement phantom containing small, well-defined structural defects (diameter, 0.1-0.4 mm). These small inhomogeneities could reliably be detected by comparing the variances of radiodensities of a region of interest (i.e., a region containing a hole) with a homogenous region. The Fligner-Killeen test was used to predict the presence or absence of a hole (p ≥ 0.05). For our second goal, that is, to see how this technique could be applied to the detection of a possible dehiscence in a SC, a cadaveric head specimen was used to create an anatomic model for a borderline SCD; the SC was drilled to the point of translucency. After semi-automatically fitting the location of the canal, our variance-based approach allowed a clear, significant detection of the thin remaining bone layer. RESULTS: Our approach of statistical noise analysis on bone cement phantoms allowed us to distinguish real irregularities from measured image noise or reconstruction errors. We have shown that with computed tomography, an approach comparing radiodensity variance in regions of interest is capable of detecting inhomogeneities down to 0.1 mm (p ≤ 0.0001). CONCLUSION: Our analysis of data from the cadaveric head specimen demonstrates that this approach can be used to objectively detect thin layers of bone overlying an SC. This should provide the basis for using this approach for a semi-automated, objective detection of SCD.