Figure 1.

Region and summary risk estimates (β-coefficient and 95% CI) for a doubling in NO₂ levels (A) and benzene levels (B) during pregnancy and infant mental development, adjusted for psychologist, child’s sex, child’s age at mental development assessment, maternal education, maternal age, maternal height and prepregnancy body mass index, maternal alcohol use during pregnancy, maternal large fatty and lean fish consumption at first trimester, season-specific maternal circulating vitamin D level at pregnancy, use of gas stove at home during pregnancy, and number of siblings at birth. (A) Test for heterogeneity: Q = 11.314 on three degrees of freedom (p = 0.010). (B) Test for heterogeneity: Q = 7.084 on three degrees of freedom (p = 0.068). The size of the markers for each β-coefficient represents the relative weight that each region contributed to the summary regression slope.