Black Carbon Associated With Cognition Among Children in a Prospective Birth Cohort Study

ISEE-677 Objective: Studies have shown that ultra fine particles from traffic can enter and possible damage the brain. We examined the relationship between black carbon, a surrogate of mobile sources, and cognitive function among children in the Maternal-Infant Smoking Study of East Boston, a prospective cohort of children enrolled before 20 weeks gestation. Materials and Methods: Black carbon exposure levels were estimated using a validated spatiotemporal land use regression model, derived using ambient and indoor monitor data, based on children's residence during study follow-up. The Wide Range Assessment of Memory and Learning (WRAML) and Kaufman Brief Intelligence Test (KBIT) were administered to children 8 to 11 years of age. Associations between predicted black carbon and cognition were examined using linear regression adjusting for race, maternal education, child's gender, age, height, birth weight, blood lead, in utero tobacco smoke, and second hand smoke exposure. Results: The sample of 201 children included 52% girls, 57% who primarily spoke Spanish at home, and 42% whose mothers reported less than a high school education. The mean ± SD predicted annual black carbon was 0.56 + 0.1 μg/m3; mean KBIT composite IQ score was 95.0 + 13.9. In adjusted analysis black carbon (per interquartile range) was associated with a 2 point (95% CI −5.4, 1.4) decrease in the vocabulary a 4.2 (95% CI −7.8, −0.7) decrease in the matrices and a 3.4 (95% CI −6.6, −0.3) decrease in the composite IQ subscales of the KBIT. Black carbon was also associated with decreases on the visual subscale (4.9 95% CI −8.4, −1.5) on the WRAML as well as the verbal and learning subscales, although the latter did not reach statistical significance. Conclusions: Higher levels of traffic-related black carbon predicted decreased cognitive function even when adjusting for tobacco smoke, birth weight, blood lead, and socioeconomic status. These findings were consistent across assessments of verbal and nonverbal intelligence and memory constructs. Funding: T32ES007142, K08HL04187, R01 HL080674.