Fig. 1
From: Preterm birth and PM2.5 in Puerto Rico: evidence from the PROTECT birth cohort
Risk ratios and 95% confidence intervals of preterm birth for an interquartile range increase in prenatal PM2.5 exposure among participants in the PROTECT cohort in Puerto Rico. Model 1: Adjusted for individual-level covariates, including mother’s age, number of other children (alive or deceased), infant’s sex, gestational age, season of birth, education level, urban/rural residence, marital status, number of prenatal visits attended, and year of birth. Model 2: Model 1 plus adjustment for area/municipality-level covariates, including population density, household income per capita, proportion of non-white non-Hispanic residents, average unemployment rate, proportion of occupied housing units with at least one of four severe US Department of Housing and Urban Development-designated defects, percentage of residents with a less than high school level of education, and the age adjusted prevalence of diabetes mellitus