Factores sociodemográficos asociados con los modos de transporte en escolares y adolescentes mexicanos / Commuting to school among Mexican schoolchildren and adolescents

Resumen Introducción: Los modos activos de transporte (caminar o andar en bicicleta) tienen efectos benéficos para la salud, por lo cual deben identificarse factores que los promuevan. El objetivo de este estudio fue analizar la relación de los modos de transporte utilizados por la población pediátrica mexicana para acudir a la escuela con las características sociodemográficas, socioeconómicas y de inseguridad pública a nivel estatal. Métodos: Se estimó la frecuencia de los modos de transporte utilizados por los escolares y adolescentes para trasladarse a la escuela (con la base de la Encuesta Intercensal 2015). En un análisis ecológico (i.e., entidades federativas como unidades de observación) se obtuvieron correlaciones con estadísticas a nivel estatal con inseguridad alimentaria, nivel de urbanización y mortalidad por muertes violentas. Resultados: El modo de transporte más frecuente fue caminar (66.2%), seguido por el automóvil (16.2%) y el transporte público (15.3%). El transporte activo fue más frecuente en individuos del sexo masculino, escolares, personas de nivel socioeconómico bajo, zonas rurales, la región sur y aquellos cuyo traslado requería menos de 15 minutos. El transporte pasivo fue más frecuente en individuos del sexo femenino, adolescentes, personas de nivel socioeconómico alto y en zonas urbanas. En los estados más urbanizados fue menos frecuente el transporte activo y más prevalente el trasporte motorizado. La inseguridad pública se relacionó negativamente con el uso de bicicleta. Conclusiones: Se requiere mantener o incrementar el uso de modos de transporte activos en la población pediátrica mexicana mediante políticas públicas que mejoren el entorno y garanticen ambientes seguros.

Abstract Background: Active commuting (walking or cycling) is associated with benefits to health; thus, it is required to identify factors that promote it. The objective of this study was to analyze the relationship between the transport modes used by Mexican pediatric population to commute to school with sociodemographic and socioeconomic individual characteristics and public insecurity at the state level. Methods: The frequency of transport modes used by schoolchildren and adolescents to commute to school (walking, cycling, private car and public transport) were estimated using the database of the Encuesta Intercensal 2015. In an ecological analysis (i.e., states as observation units) correlations with food insecurity, urbanization level, and violent deaths statistics at state-level were obtained. Results: The most frequent transportation mode was walking (66.2%), followed by car (16.2%) and public transportation (15.3%). Active commuting (walking or cycling) was more frequent in males, schoolchildren, low socioeconomic status, living in rural or southern areas and those who spent <15 min to commute. Passive commute was more frequent among females, adolescents, high socioeconomic status, and living in urban areas. In the more urbanized states, active transportation was less frequent, but motorized transportation was more prevalent. Public insecurity was negatively related to cycling. Conclusions: Maintaining or increasing active commuting among Mexican pediatric population is necessary through public policies aimed to improve physical and social environment.

Commuting to school among Mexican schoolchildren and adolescents.

Background: Active commuting (walking or cycling) is associated with benefits to health; thus, it is required to identify factors that promote it. The objective of this study was to analyze the relationship between the transport modes used by Mexican pediatric population to commute to school with sociodemographic and socioeconomic individual characteristics and public insecurity at the state level. Methods: The frequency of transport modes used by schoolchildren and adolescents to commute to school (walking, cycling, private car and public transport) were estimated using the database of the Encuesta Intercensal 2015. In an ecological analysis (i.e., states as observation units) correlations with food insecurity, urbanization level, and violent deaths statistics at state-level were obtained. Results: The most frequent transportation mode was walking (66.2%), followed by car (16.2%) and public transportation (15.3%). Active commuting (walking or cycling) was more frequent in males, schoolchildren, low socioeconomic status, living in rural or southern areas and those who spent <15 min to commute. Passive commute was more frequent among females, adolescents, high socioeconomic status, and living in urban areas. In the more urbanized states, active transportation was less frequent, but motorized transportation was more prevalent. Public insecurity was negatively related to cycling. Conclusions: Maintaining or increasing active commuting among Mexican pediatric population is necessary through public policies aimed to improve physical and social environment.

Introducción: Los modos activos de transporte (caminar o andar en bicicleta) tienen efectos benéficos para la salud, por lo cual deben identificarse factores que los promuevan. El objetivo de este estudio fue analizar la relación de los modos de transporte utilizados por la población pediátrica mexicana para acudir a la escuela con las características sociodemográficas, socioeconómicas y de inseguridad pública a nivel estatal. Métodos: Se estimó la frecuencia de los modos de transporte utilizados por los escolares y adolescentes para trasladarse a la escuela (con la base de la Encuesta Intercensal 2015). En un análisis ecológico (i.e., entidades federativas como unidades de observación) se obtuvieron correlaciones con estadísticas a nivel estatal con inseguridad alimentaria, nivel de urbanización y mortalidad por muertes violentas. Resultados: El modo de transporte más frecuente fue caminar (66.2%), seguido por el automóvil (16.2%) y el transporte público (15.3%). El transporte activo fue más frecuente en individuos del sexo masculino, escolares, personas de nivel socioeconómico bajo, zonas rurales, la región sur y aquellos cuyo traslado requería menos de 15 minutos. El transporte pasivo fue más frecuente en individuos del sexo femenino, adolescentes, personas de nivel socioeconómico alto y en zonas urbanas. En los estados más urbanizados fue menos frecuente el transporte activo y más prevalente el trasporte motorizado. La inseguridad pública se relacionó negativamente con el uso de bicicleta. Conclusiones: Se requiere mantener o incrementar el uso de modos de transporte activos en la población pediátrica mexicana mediante políticas públicas que mejoren el entorno y garanticen ambientes seguros.

Spontaneous recovery of fear reverses extinction-induced excitability of infralimbic neurons.

In rodents, the infralimbic (IL) region of the medial prefrontal cortex plays a key role in the recall of fear extinction. Previously we showed that fear conditioning decreases the intrinsic excitability of IL neurons, and that fear extinction reverses the depressed excitability. In the current study, we examined the time course of the extinction-induced changes in adolescent rats. Immediately after extinction, IL neurons continued to show depressed excitability. However 4 hours after extinction, IL neurons showed an increase in evoked spikes that correlated with a reduced fast afterhyperpolarizing potential. This suggests that acquisition of fear extinction induces an increase in spike firing 4 hours later, during the consolidation of extinction. We also examined IL excitability in a group of rats that showed spontaneous recovery of fear 17 days after extinction (SR group). Similar to neurons after fear conditioning, IL neurons from the SR group showed depressed intrinsic excitability compared to neurons 4 hours after extinction, suggesting that extinction-induced enhancement in intrinsic excitability decreases with time reverting back to a depressed state. These results suggest that plasticity in IL contributes to the spontaneous recovery of fear and preventing this depression of IL excitability could prolong fear extinction.

Fear extinction induces mGluR5-mediated synaptic and intrinsic plasticity in infralimbic neurons.

Studies suggest that plasticity in the infralimbic prefrontal cortex (IL) in rodents and its homolog in humans is necessary for inhibition of fear during the recall of fear extinction. The recall of extinction is impaired by locally blocking metabotropic glutamate receptor type 5 (mGluR5) activation in IL during extinction training. This finding suggests that mGluR5 stimulation may lead to IL plasticity needed for fear extinction. To test this hypothesis, we recorded AMPA and NMDA currents, AMPA receptor (AMPAR) rectification, and intrinsic excitability in IL pyramidal neurons in slices from trained rats using whole-cell patch-clamp recording. We observed that fear extinction increases the AMPA/NMDA ratio, consistent with insertion of AMPARs into IL synapses. In addition, extinction training increased inward rectification, suggesting that extinction induces the insertion of calcium-permeable (GluA2-lacking) AMPARs into IL synapses. Consistent with this, selectively blocking calcium-permeable AMPARs with Naspm reduced the AMPA EPSCs in IL neurons to a larger degree after extinction. Extinction-induced changes in AMPA/NMDA ratio, rectification, and intrinsic excitability were blocked with an mGluR5 antagonist. These findings suggest that mGluR5 activation leads to consolidation of fear extinction by regulating the intrinsic excitability of IL neurons and modifying the composition of AMPARs in IL synapses. Therefore, impaired mGluR5 activity in IL synapses could be one factor that causes inappropriate modulation of fear expression leading to anxiety disorders.