Associations between ambient air pollution and noise from road traffic with blood pressure and insulin resistance in children from Denmark

BACKGROUND: Road traffic is a major source of air pollution and noise. Both exposures may contribute to increased blood pressure and metabolic disease; however, few studies have examined these relationships in children. OBJECTIVES: We aimed to investigate whether long-term exposures to air pollution and noise from road traffic were associated with increased blood pressure and insulin resistance in children. METHODS: Cardiometabolic outcomes were derived from a follow-up examination of 629 children (10–15 years old) enrolled in the Danish National Birth Cohort. We evaluated associations with prenatal and postnatal residential exposure to nitrogen dioxide (NO(2)) and noise from road traffic (L(den)) using historical addresses and linear regression models. RESULTS: A 10-unit increase in postnatal exposure to NO(2) and L(den) was associated with a 0.31 (−0.87, 1.48) and 0.18 (−0.61, 0.96) mmHg changes in diastolic blood pressure, respectively. In contrast, both exposures were associated with decreased systolic blood pressure. After adjustment and mutual adjustment for NO(2), exposure to L(den) was associated with a statistical significant decrease in systolic blood pressure both during prenatal and postnatal life, but the majority of the associations evaluated did not reach statistical significance. Inverse associations were observed for plasma fasting glucose, insulin, and HOMA of insulin resistance for both exposures, exposure windows, before and after adjustment. CONCLUSIONS: The findings do not support evidence of associations between long-term exposures to air pollution and road traffic noise, increased blood pressure, and a metabolic profile characteristic of increased risk for glucose intolerance or type 2 diabetes later in life.