Neurocognitive function in adult residents of a mining district in Mexico after reducing manganese exposure: Follow-up after 11 years.

BACKGROUND: Little is known about the neurotoxic effects of chronic exposure to airborne Mn once exposure has been reduced. The environmentally exposed and the reference adult populations evaluated in 2002 were followed, after an environmental management program (EMP) was implemented to reduce the exposure in a mining district in Mexico. OBJECTIVE: The aim of this study was to compare the association between exposure to Mn and neurocognitive performance in environmentally exposed and reference groups of adults before and after EMP implementation. METHODS: In 2013, the same battery of neurocognitive tests used in the initial study (2002) was applied to 58 adults exposed to airborne Mn and 30 adults from the reference community. A cumulative exposure index (CEI) was estimated for the study population before and after the EMP. Categorical outcomes were analyzed using logistic regression, and the resulting ORs were compared between studies. Continuous outcomes were analyzed using linear regression. All models were adjusted for age, years of education, socioeconomic status and blood lead levels. RESULTS: Exposed adults from the post-EMP study showed an improvement in fine motor and verbal regulation of motor skills (OR < 1) compared to the exposed adults from the pre-EMP study (OR > 1). In both pre- and post-studies, the exposed adults showed a deterioration in their dynamic organization of motor activity compared to the reference group (p < 0.05); however, they showed no significant change in attention and working-memory performance. DISCUSSION: After four years of a significant reduction in airborne Mn levels resulting from EMP implementation, chronically exposed adults showed an improvement in fine motor and verbal regulation of motor skills; however, the remaining areas of their motor and cognitive functions remained impaired.

Verbal Memory and Learning in Schoolchildren Exposed to Manganese in Mexico.

Manganese (Mn) is an essential nutrient for cellular function, but in high concentrations, it is neurotoxic. Environmental exposure to Mn has been associated with cognitive effects in children. This study aimed to assess the effect of environmental exposure to Mn on verbal memory and learning in schoolchildren residents from two municipalities in the state of Hidalgo, Mexico. Cross-sectional studies were conducted in 2006 and 2013 with a total of 265 schoolchildren of 7 to 11 years old. Children's Auditory Verbal Learning Test-2 (CAVLT-2) was used to assess verbal memory and learning. Mn exposure tertiles were defined according to hair manganese (MnH) levels determined by atomic absorption spectrophotometry. Linear regression models were used to estimate the association between MnH levels and CAVLT-2 scores. The models were adjusted by potential confounders. The lowest and highest exposure tertiles were defined below and above MnH levels of ≤ 0.72 and ≥ 3.96 µg/g, respectively. Mn exposure was significantly associated with an average of 5- to 9-point decrease in learning curves and summary CAVLT-2 scores in the highest tertile. This study adds to the evidence of decreased verbal memory and learning in schoolchildren environmentally exposed to manganese.

Mapeo Comunitario para impulsar la participación comunitaria dentro del diagnóstico de salud poblacional / Boosting community participation in the diagnosis of population health through community mapping / Mapeamento Comunitário para impulsionar a participação comunitária dentro do diagnóstico de saúde populacional

Resumen Introducción: La salud pública tiene en el diagnóstico de salud poblacional una de las principales herramientas de investigación y planificación sanitaria. La participación activa de la población en el diagnóstico poblacional es fundamental y el mapeo comunitario es una técnica que la promueve. Objetivo: Presentar las aportaciones del uso del mapeo comunitario para la participación de la población durante el desarrollo del diagnóstico de salud poblacional. Métodos: Para dar evidencia de las aportaciones de ésta técnica, durante el desarrollo de los diagnósticos de salud, efectuados entre los años 2010 y 2014, en zonas rurales y suburbanas del centro de México, se efectuaron ejercicios de mapeo comunitario con diversos grupos poblacionales (niños, jóvenes y adultos de ambos sexos), quienes identificaban en el mapa aspectos tanto positivos como negativos de su comunidad, lo cual se plasmó en necesidades sentidas de la población. Resultados: A través del mapeo comunitario se despertó el interés y se logró estimular la participación poblacional en la identificación de necesidades, priorización de problemas y soluciones. Conclusiones: La inclusión del mapeo comunitario dentro del diagnóstico poblacional, propicia la participación y fortalece procesos organizativos, lo cual permite que se busquen soluciones a las problemáticas identificadas.

Abstract Introduction: Public health has, in the diagnosis of population health, a main researching and sanitary planning tool. The diagnosis of population health is a fundamental task, and community mapping is a technique which promotes the active participation of people. Objective: To show the input from the use of community mapping for boosting the population participation during the diagnosis of population health. Methods: In order to provide evidence on the input from this technique, during the development of the health diagnoses between 2010 and 2014, in rural and suburban zones in central Mexico, community mapping drills were carried out with diverse population groups (children, young, and adults, from both sexes) who identified positive and negative issues of their community, thus giving shape to a community map of their needs. Results: By using the community mapping technique, the participation of the people in the identification of needs and prioritization of problems and solutions was stimulated. Conclusions: The inclusion of the community mapping technique in the population diagnosis fosters the participation and strengthens organizational processes allowing a better response to the identified problems.

Resumo Introdução: A saúde pública tem no diagnóstico de saúde populacional uma das principais ferramentas de pesquisa e planificação sanitária. A participação ativa da população no diagnóstico populacional é fundamental e o mapeamento comunitário é uma técnica que a promove. Objetivo: Apresentar as contribuições do uso do mapeamento comunitário para a participação da população durante o desenvolvimento do diagnóstico de saúde populacional. Métodos: Para dar evidencia das contribuições desta técnica, durante o desenvolvimento dos diagnósticos de saúde, efetuados entre os anos 2010 e 2014, em zonas rurais e suburbanas do centro do México, efetuaram-se exercícios de mapeamento comunitário com diversos grupos populacionais (crianças, adolescentes e adultos de ambos os sexos), quem identificava no mapa aspectos tanto positivos quanto negativos de sua comunidade, o qual se retratou nas necessidades sentidas da população. Resultados: A través do mapeamento comunitário acordou-se o interesse e conseguiu-se estimular a participação populacional na identificação de necessidades, priorização de problemas e soluções. Conclusões: A inclusão do mapeamento comunitário dentro do diagnóstico populacional, propicia a participação e fortalece processos organizativos, o qual permite que se procurem soluções às problemáticas identificadas.

Effects of manganese exposure on visuoperception and visual memory in schoolchildren.

BACKGROUND: Manganese (Mn) is an essential metal involved in multiple physiological functions. Environmental exposure to airborne Mn is associated with neurocognitive deficits in humans. Children, whose nervous system is in development, are particularly susceptible to Mn neurotoxicity. OBJECTIVE: The objective of this study was to assess the association between Mn environmental exposure, and effects on visuoperception and visual memory in schoolchildren. METHODS: We assessed schoolchildren between 7 and 11 years old, with similar socioeconomic status, from the mining district of Molango (n=148) and Agua Blanca (n=119, non-mining area) in Hidalgo state, Mexico. The Rey-Osterrieth Complex Figure (ROCF) test was used to assess visuoperception and short-term visual memory. Hair manganese (MnH) concentrations were determined. Linear regression models were constructed to estimate the associations between MnH and ROCF scores, adjusted for potential confounders. RESULTS: The geometric mean MnH was nine times higher in schoolchildren from the Mn mining area (5.25µg/g) than in schoolchildren from the non-mining area (0.55µg/g). For the ROCF Copy trial, MnH was significantly associated with an increase in distortion errors (tangency, closure), angle errors, overtracing (partial overtracing). In the Immediate Recall trial, MnH was significantly associated with increased overtracing (partial overtracing) and omissions, and negatively associated with the number of perceptual drawn units, total score and percentage immediate recall. CONCLUSIONS: MnH is associated with alterations in visuoperception and short-term visual memory in schoolchildren exposed to airborne Mn.

Effect of environmental manganese exposure on verbal learning and memory in Mexican children.

Manganese (Mn) is an essential metal, but in excess it becomes neurotoxic. Children's developing nervous system may be especially vulnerable to the neurotoxic effects of overexposure to this metal. The aim of this study was to assess the effect of Mn exposure on verbal memory and learning in 7- to 11-year-old children. We tested 79 children living in the Molango Mn-mining district and 95 children from a non-exposed community in the same State of Mexico. The Children's Auditory Verbal Learning Test (CAVLT) was administered. Blood and hair samples were obtained to determine Mn concentrations using atomic absorption spectrophotometry. CAVLT performance was compared between the two groups and multilevel regression models were constructed to estimate the association between biomarkers of Mn exposure and the CAVLT scores. The exposed group presented higher hair and blood Mn (p<0.001) than the non-exposed group (median 12.6 vs. 0.6µg/g, 9.5vs. 8.0µg/L respectively), as well as lower scores (p<0.001) for all the CAVLT subscales. Hair Mn was inversely associated with most CAVLT subscales, mainly those evaluating long-term memory and learning (ß=-0.47, 95% CI -0.84, -0.09). Blood Mn levels showed a negative but non-significant association with the CAVLT scores. These results suggest that Mn exposure has a negative effect on children's memory and learning abilities.

Elemental carbon exposure and lung function in school children from Mexico City.

Though exposure to air pollution has a detrimental effect on respiratory health, few studies have examined the association between elemental carbon exposure and lung function among schoolchildren. The aim of the present study was to present the association between short-term elemental carbon exposure and lung function in schoolchildren from Mexico City. 55 asthmatic and 40 non-asthmatic children were followed for an average of 22 weeks. A spirometry test was performed every 15 days during follow-up. Portable air samplers collected particulate matter onto Teflon filters. Gravimetric analysis was conducted and elemental carbon was quantified using transmission densitometry. The association between the main variables was analysed using linear mixed effects models. The mean ± sd of elemental carbon light absorption was 92.7 ± 54.7 Mm(-1). An increase of one interquartile range in the 24-h average of elemental carbon (100.93 Mm(-1)) was associated with a significant negative impact on forced expiratory volume in 1 s (FEV(1)) (-62.0 (95% CI -123.3- -1.2) mL) and forced expiratory flow at 25-75% of forced vital capacity (FVC) (FEF(25-75%)) (-111 (95% CI -228.3- -4.1) mL) among asthmatic children, equal to 3.3% and 5.5%, respectively; and on FEV(1) (-95.0 (95% CI -182.3- -8.5) mL) and FVC (-105.0 (95% CI -197.0- -13.7) mL) among non-asthmatic children. Exposure to elemental carbon resulted in an important negative effect on lung function in atopic schoolchildren, regardless of asthma status.

[Evaluation of the indoor and outdoor air quality in a nursery school in Mexico City]. / Evaluación de la calidad del aire interior y exterior en un jardín de niños de la Ciudad de México.

OBJECTIVE: To evaluate the differences between indoor and outdoor ozone (O3) and nitrogen dioxide (NO2) levels at a school located in southwest Mexico City. MATERIAL AND METHODS: Indoor and outdoor O3 and NO2 levels were measured daily between January and April 1990 by manual monitoring. RESULTS: Indoor and outdoor concentrations of nitrogen dioxide did not surpass the Mexican standard (0.21 ppm). The correlation coefficient between maximum NO2 concentrations measured by the city's local monitoring station and those measured outside the classroom was 0.82 (p < 0.001). Regarding ozone, its maximum outdoor concentration was 0.29 ppm and indoor concentrations were on average below 0.06 ppm (maximum = 0.17 ppm). The indoor/outdoor correlation coefficient was 0.72, and for every 1.7 ppm outside, there was 1.0 ppm inside (p < 0.05). CONCLUSIONS: Since the highest outdoors O3 concentrations were observed between 11:00 and 14:00 hrs, it is recommendable to have recess before this time.

[Study of the validity and reproducibility of passive ozone monitors]. / Estudio de validación y reproducibilidad de monitores pasivos a ozono.

The aim of this study was to evaluate the validity and reproducibility between ozone measurements obtained with passive ozone monitors and those registered with a continuous ozone monitor, to determine the applicability of passive monitors in epidemiological research. The study was carried out during November and December 1992. Indoor and outdoor classroom air ozone concentrations were analyzed using 28 passive monitors and using a continuous monitor. The correlation between both measurements was highly significant (r = 0.089, p < 0.001), indicating a very good validity. Also, the correlation between the measurements obtained with two different passive monitors exposed concurrently was very high (r = 0.97, p < 0.001), indicating a good reproducibility in the measurements of the passive monitors. The relative error between the concentrations measured by the passive monitors and those from the continuous monitor tended to decrease with increasing ozone concentrations. The results suggest that passive monitors should be used to determine cumulative exposure of ozone exceeding 100 ppb, corresponding to an exposure period greater than five days, if used to analyze indoor air.