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Speed limits are an evidence-based intervention to prevent traffic collisions and deaths, yet their impact on air pollution in cities is understudied. The objective of this study was to investigate the association between lower speed limits and air pollution. We leverage the introduction of a new road safety policy in Mexico City in December 2015 which lowered speed limits, increased fines, and installed speed radars to enforce compliance. We tested whether the policy had an impact on particulate matter (PM2.5) and nitrogen dioxide (NO2) at the city level, and whether air-quality monitoring stations' proximity to speed radars moderated this effect due to more acceleration and deceleration around radars. NO2 and PM2.5 concentrations from January 2014 to December 2018 were obtained from the National System of Air Quality Information. Air-quality monitoring stations were classified as in close-proximity or far-from-speed radars. Interrupted time series analyses were conducted for each outcome separately, using linear mixed models and adjusting for seasonality and time-varying confounders: registered vehicles, temperature, wind-speed and relative humidity. The results suggest improvement in both contaminants after the speed limits policy. For NO2, the pre-policy trend was flat, while the post-policy trend showed a decline in concentrations of 0.04 ppb/week. For PM2.5, concentrations were increasing pre-policy by 0.08 µg/m3 per week, then this trend flattened in the post-policy period to a weekly, non-significant, increase of 0.03 µg/m3 (p = 0.08). Air-quality monitors' proximity to speed radars did not moderate the effect of the policy on either of the pollutants. In conclusion, the speed limits policy implemented in Mexico City in 2015 was associated with improvements in air pollution.

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BACKGROUND: PM2.5 exposure has been associated with intima-media thickness (cIMT) increase. However, very few studies distinguished between left and right cIMT in relation to PM2.5 exposure. AIM: To evaluate associations between chronic exposure to PM2.5 and cIMT at bilateral, left, and right in adults from Mexico City. METHODS: This study comprised 913 participants from the control group, participants without personal or family history of cardiovascular disease, of the Genetics of Atherosclerosis Disease Mexican study (GEA acronym in Spanish), recruited at the Instituto Nacional de Cardiología Ignacio Chávez from June 2008 to January 2013. To assess the associations between chronic exposure to PM2.5 (per 5 µg/m3 increase) at different lag years (1-4 years) and cIMT (bilateral, left, and right) we applied distributed lag non-linear models (DLNMs). RESULTS: The median and interquartile range for cIMT at bilateral, left, and right, were 630 (555, 735), 640 (550, 750), and 620 (530, 720) µm, respectively. Annual average PM2.5 exposure was 26.64 µg/m3, with median and IQR, of 24.46 (23.5-25.46) µg/m3. Results from DLNMs adjusted for age, sex, body mass index, low-density lipoproteins, and glucose, showed that PM2.5 exposure for year 1 and 2, were positively and significantly associated with right-cIMT [6.99% (95% CI: 3.67; 10.42) and 2.98% (0.03; 6.01), respectively]. Negative associations were observed for PM2.5 at year 3 and 4 and right-cIMT; however only year 3 was statistically significant [-2.83% (95% CI: 5.12; -0.50)]. Left-cIMT was not associated with PM2.5 exposure at any lag year. The increase in bilateral cIMT followed a similar pattern as that observed for right-cIMT, but with lower estimates. CONCLUSIONS: Our results suggest different susceptibility between left and right cIMT associated with PM2.5 exposure highlighting the need of measuring both, left and right cIMT, regarding ambient air pollution in epidemiological studies.

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Lead (Pb), mercury (Hg), and manganese (Mn) are neurotoxic, but little is known about the neurodevelopmental effects associated with simultaneous prenatal exposure to these metals. We aimed to study the associations of Pb, Hg, and Mn prenatal levels (jointly and separately) with neurodevelopment in the first year of life. Methods: Pb, Hg, and Mn blood lead levels were measured in 253 pregnant women. Their offspring's neurodevelopment was assessed through the Bayley Scale of Infant Development III® at one, three, six, and twelve months. The metals' mean blood levels (µg/L) were Pb = 11.2, Hg = 2.1, and Mn = 10.2. Mean language, cognitive, and motor development scores of the infants at each age were between low-average and average. Multilevel models' results showed that language development coefficients of the offspring decreased by 1.5 points per 1 µg/dL increase in maternal blood lead levels (p = 0.002); the magnitude of the aforementioned association increased in children with maternal blood Mn < 9.6 µg/L (ß = -1.9, p = 0.003) or Hg > 1.9 µg/L (ß = -1.6, p = 0.013). Cognitive and motor development had negative associations with maternal blood Pb levels; the latter was statistically significant when the interaction term between Pb, Mn, and Hg was included (ß = -0.037, p = 0.03). Prenatal exposure to low Pb levels may impair infants' neurodevelopment in the first year of life, even more so if they are exposed to Hg or deficient in Mn.

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Self-help groups (SHGs) for people living with HIV (PLHIV) are organizations created by the community to provide individuals with security, affection, improved self-esteem, and a sense of belonging. However, SHGs have also been used by the government to help implement HIV control policies. This study aimed to identify the characteristics associated with the use of SHGs by PLHIV and the routes and displacement patterns adopted by users. An analytical cross-sectional study was conducted based on data collected in six Central American countries during 2012. Using a list of SHGs, a random sampling was conducted in two stages. Firstly, the SHGs were selected. Then, the selected SHGs were visited and every third user who attended the SHG was surveyed. Logistic regression models were used to identify the characteristics associated with the use of SHGs and with attending the nearest SHGs. A spatial analysis was performed to identify the routes followed by users to reach the SHGs from their home communities. We found that the characteristics significantly associated with higher odds of SHG usage were country of residence and schooling level. The average and median distances traveled by users to attend SHGs were 20 and 5 kilometers, respectively. PLHIV do not use the SHGs closest to their locality, perhaps for fear of stigma and discrimination. We recommend that research on this topic use a mixed qualitative-quantitative methodology to better understand utilization decisions, user expectations, and the degree to which these are being met.

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(1) Background: Epidemiological studies have identified associations between fine particulate matter (PM2.5) and ozone exposure with cardiovascular disease; however, studies linking ambient air pollution and premature coronary artery disease (pCAD) in Latin America are non-existing. (2) Methods: Our study was a case−control analysis nested in the Genetics of Atherosclerotic Disease (GEA) Mexican study. We included 1615 participants (869 controls and 746 patients with pCAD), recruited at the Instituto Nacional de Cardiología Ignacio Chávez from June 2008 to January 2013. We defined pCAD as history of myocardial infarction, angioplasty, revascularization surgery or coronary stenosis > 50% diagnosed before age 55 in men and age 65 in women. Controls were healthy individuals without personal or family history of pCAD and with coronary artery calcification equal to zero. Hourly measurements of ozone and PM2.5 from the Atmospheric Monitoring System in Mexico City (SIMAT in Spanish; Sistema de Monitero Atmosférico de la Ciudad de México) were used to calculate annual exposure to ozone and PM2.5 in the study participants. (3) Results: Each ppb increase in ozone at 1-year, 2-year, 3-year and 5-year averages was significantly associated with increased odds (OR = 1.10; 95% CI: 1.03−1.18; OR = 1.17; 95% CI: 1.05−1.30; OR = 1.18; 95% CI: 1.05−1.33, and OR = 1.13; 95% CI: 1.04−1.23, respectively) of pCAD. We observed higher risk of pCAD for each 5 µg/m3 increase only for the 5-year average of PM2.5 exposure (OR = 2.75; 95% CI: 1.47−5.16), compared to controls. (4) Conclusions: Ozone exposure at different time points and PM2.5 exposure at 5 years were associated with increased odds of pCAD. Our results highlight the importance of reducing long-term exposure to ambient air pollution levels to reduce the burden of cardiovascular disease in Mexico City and other metropolitan areas.

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Available data on the acute cardiovascular effect of ambient air pollution (AAP) in Latin America is limited considering that over 80% of its 1 billion inhabitants live in urban settlements with poor air quality. The study aim was to evaluate the association between Cardiovascular Emergency Department Visits (CEDVs) and AAP in Mexico City from 2016 to 2019 using generalized additive models with distributed lags to examine the percentage change of CEDVs and a backward approach of time-series model to calculate attributable fractions. A total of 48,891 CEDVs were recorded in a period of 1019 days. We estimated a significant percentage increase for each 10 µg/m3 of PM10 at Lag0-5 (2.8%, 95%CI 0.6-5.0), PM2.5 at Lag0-6 (3.7%, 95%CI 0.1-7.6), O3 at Lag0-5 (1.1%, 95%CI 0.2-2.0), NO2 at Lag0-4 (2.5%, 95%CI 0.3-4.7) and for each 1 mg/m3 of CO at Lag0 (6.6%, 95%CI 0.3-13.2). Overall, 10.3% of CEDVs in Mexico City may be related to PM10 exposure, 9.5% to PM2.5, 10.3% to O3, 11% to NO2 and 5.7% to CO. AAP significantly increase cardiovascular morbidity impacting on emergency medical services.

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BACKGROUND: Air pollution is a risk factor for type 2 diabetes (T2D). However, scarse longitudinal studies have evaluated this association in low- and middle-income countries, where 80% of the worldwide cases of T2D occur. OBJECTIVE: Our aim was to estimate the association between PM2.5 and NO2 exposure and incident T2D, in the Mexican Teachers' Cohort (MTC). METHODS: We selected a subsample of female teachers from the MTC from Mexico City metropolitan area (MCMA), recruited in 2008 and with active follow-up every three years. We assigned the monthly time-weighted exposures (PM2.5 and NO2) using home and work addresses, until failure, censoring or death. We developed two high resolution (1 × 1-km) spatiotemporal predictive generalized additive models of PM2.5 and NO2. Incident diabetes was identified through self-report and two administrative databases of registered diabetes patients. We fitted time-varying Cox models to estimate hazard ratios of the relation between PM2.5 and NO2 and incident T2D, adjusting for confounding variables that were identified using a causal model. RESULTS: A total of 13,669 teachers were followed-up for a maximum of 11.5 years, over which 996 incident T2D cases (88 cases per 100,000 person-months) occurred. Incident T2D increased by 72% (HR = 1.72 [1.47-2.01]) for each 10 µg/m3 increase of PM2.5, and 52% for each 10 ppb of NO2 (HR = 1.52 [1.37-1.68]). DISCUSSION: Mid-term exposure to PM2.5 and NO2 was associated with a higher risk of T2D after adjusting for indoor wood smoke, socioeconomic status, and physical activity. These associations were attenuated in two-pollutant models but remained positive when evaluated long-term exposure. This is the first prospective study to evaluate T2D risk by exposure to both pollutants, PM2.5 and NO2 in a population from an upper middle-income country in the Americas.

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Self-help groups (SHGs) for people living with HIV (PLHIV) are organizations created by the community to provide individuals with security, affection, improved self-esteem, and a sense of belonging. However, SHGs have also been used by the government to help implement HIV control policies. This study aimed to identify the characteristics associated with the use of SHGs by PLHIV and the routes and displacement patterns adopted by users. An analytical cross-sectional study was conducted based on data collected in six Central American countries during 2012. Using a list of SHGs, a random sampling was conducted in two stages. Firstly, the SHGs were selected. Then, the selected SHGs were visited and every third user who attended the SHG was surveyed. Logistic regression models were used to identify the characteristics associated with the use of SHGs and with attending the nearest SHGs. A spatial analysis was performed to identify the routes followed by users to reach the SHGs from their home communities. We found that the characteristics significantly associated with higher odds of SHG usage were country of residence and schooling level. The average and median distances traveled by users to attend SHGs were 20 and 5 kilometers, respectively. PLHIV do not use the SHGs closest to their locality, perhaps for fear of stigma and discrimination. We recommend that research on this topic use a mixed qualitative-quantitative methodology to better understand utilization decisions, user expectations, and the degree to which these are being met.

Los grupos de autoayuda (GAA) para personas que viven con el VIH (PVVIH) son organizaciones creadas por la comunidad para proporcionarles seguridad, afecto, mejor autoestima y un sentido de pertenencia. Sin embargo, el gobierno también ha utilizado los GAA para ayudar a implementar políticas de control del VIH. Se buscó identificar las características asociadas con el uso de GAA por PVVIH y las rutas y patrones de desplazamiento adoptados por los usuarios. Este es un estudio analítico transversal basado en datos recogidos en seis países centroamericanos en 2012. A través de una lista de GAA, se construyó un muestreo aleatorio de dos etapas. Primero, se seleccionaron los GAA. Luego, los participantes recibieron una visita, y se evaluó cada tercio de ellos. Se utilizaron modelos de regresión logística para identificar las características asociadas al uso y visitas a los GAA más cercanos a los usuarios. Se realizó un análisis espacial para identificar las rutas que los voluntarios tomaron para llegar a los GAA en sus comunidades de origen. Se constató que las características significativamente asociadas con mayores probabilidades de uso de los GAA fueron el país de residencia y la escolaridad. Las distancias medias y medianas recorridas por los usuarios para visitar los GAA fueron de 20 kilómetros y 5 kilómetros, respectivamente. Las PVVIH no utilizan los GAA más cercanos a su casa, tal vez por miedo al estigma y a la discriminación. Se necesitan investigaciones sobre este tema que utilicen una metodología mixta cualitativa-cuantitativa para comprender mejor las decisiones de uso, las expectativas de los usuarios y el grado en que se están atendiendo.

Grupos de autoajuda (GAAs) para pessoas vivendo com HIV (PVHIV) são organizações criadas pela comunidade para proporcioná-los segurança, afeto, melhor autoestima e senso de pertencimento. No entanto, o governo também tem usado os GAAs para ajudar a implementar políticas de controle do HIV. Buscamos identificar as características associadas ao uso de GAAs por PVHIV e as rotas e padrões de deslocamento adotados pelos usuários. Este é um estudo analítico transversal realizado com base em dados coletados em seis países da América Central em 2012. Através de uma lista de GAAs, uma amostragem aleatória em dois estágios foi construída. Em primeiro lugar, os GAAs foram selecionados. Em seguida, eles foram visitados e cada terceiro de seus participantes foi avaliado. Foram utilizados modelos de regressão logística para identificar as características associadas ao uso e às visitas aos GAAs mais próximos aos usuários. Foi realizada uma análise espacial para identificar as rotas que voluntários tomavam para chegar aos GAAs em suas comunidades de origem. Verificamos que as características significativamente associadas com maiores chances de uso dos GAAs foram país de residência e escolaridade. As distâncias médias e medianas percorridas por usuários para visitar os GAAs foram de 20 quilômetros e 5 quilômetros, respectivamente. As PVHIV não utilizam os GAAs mais próximos de onde moram, talvez por medo de estigma e discriminação. Recomendamos que as pesquisas sobre este tema utilizem uma metodologia qualitativa-quantitativa mista para entender melhor as decisões de utilização, as expectativas dos usuários e o grau em que eles estão sendo atendidos.

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Health effects related to exposure to air pollution such as ozone (O3) have been documented. The World Health Organization has recommended the use of the Sum of O3 Means Over 35 ppb (SOMO35) to perform Health Impact Assessments (HIA) for long-term exposure to O3. We estimated the avoidable mortality associated with long-term exposure to tropospheric O3 in 14 cities in Mexico using information for 2015. The economic valuation of avoidable deaths related to SOMO35 exposure was performed using the willingness to pay (WTP) and human capital (HC) approaches. We estimated that 627 deaths (95% uncertainty interval (UI): 227-1051) from respiratory diseases associated with the exposure to O3 would have been avoided in people over 30 years in the study area, which confirms the public health impacts of ambient air pollution. The avoidable deaths account for almost 1400 million USD under the WTP approach, whilst the HC method yielded a lost productivity estimate of 29.7 million USD due to premature deaths. Our findings represent the first evidence of the health impacts of O3 exposure in Mexico, using SOMO35 metrics.

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Exposure to PM2.5 has been associated with the prevalence of obesity. In the Greater Mexico City Area (GMCA), both are ranked among the highest in the world. Our aim was to analyze this association in children, adolescents, and adults in the GMCA. We used data from the 2006 and 2012 Mexican National Surveys of Health and Nutrition (ENSANUT). Participants' past-year exposure to ambient PM2.5 was assessed using land use terms and satellite-derived aerosol optical depth estimates; weight and height were measured. We used survey-adjusted logistic regression models to estimate the odds ratios (ORs) of obesity (vs. normal-overweight) for every 10 µg/m3 increase in annual PM2.5 exposure for children, adolescents, and adults. Using a meta-analysis approach, we estimated the overall odds of obesity. We analyzed data representing 19.3 million and 20.9 million GMCA individuals from ENSANUT 2006 and 2012, respectively. The overall pooled estimate between PM2.5 exposure and obesity was OR = 1.96 (95% CI: 1.21, 3.18). For adolescents, a 10 µg/m3 increase in PM2.5 was associated with an OR of 3.53 (95% CI: 1.45, 8.58) and 3.79 (95% CI: 1.40, 10.24) in 2006 and 2012, respectively. More studies such as this are recommended in Latin American cities with similar air pollution and obesity conditions.

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