Associations between Children's Physical Activity and Exposures to Air Temperature and Green Space in Mexico City

Background/Aim: Global increases in sedentary behavior are a major public health concern requiring research into its causes. We investigate environmental factors such as temperature and green space that may predict physical activity among children 4-6 years of age, since active children are more likely to exercise regularly over the course of their life.Methods: We use children’s data collected in the years 2013-15 in a subset of the Mexico City PROGRESS cohort (n=383). Children wore accelerometers for a week recording their activity levels. For physical activity, we calculated mean, maximum, and minimum hourly vertical counts by day and by week. We estimated children’s exposure to green space using 50m resolution seasonal maximum NDVI (Normalized Difference Vegetation Index), a satellite-based measure of greenness; and exposure to air temperature with a daily 1km resolution model developed by our group using data from satellite-based land surface temperature and weather stations (CV R2...