Perinatal & Pediatric
Blood Lead Levels and Risk of Asthma amongst an Urban Clinical Cohort of Children Yijun Liu* Yijun Liu Jing Nie Heather K. Lehman Marina Oktapodas Feiler
Objective
To explore the association between peak blood lead levels (BLL) and subsequent asthma diagnosis in an urban clinical cohort of children who received health care through the Temple University Hospital System (TUHS) in Philadelphia, PA, between 2010 and 2020.
Study design
We conducted a retrospective cohort study using electronic health record (EHR) data from TUHS. Eligible participants included all children 10 years of age or younger with at least one laboratory measured BLL (N=14,217). Peak BLL (µg/dl) were extracted from laboratory test results in the EHR. Log-binomial regression models were fit to estimate the risk ratios (RR) and 95% confidence intervals (CI) between BLLs and asthma diagnosis (captured by ICD codes), adjusting for race, insurance, and age at blood sample collection. Secondary outcomes included asthma severity and exacerbations.
Results
A total of 3488 participants were diagnosed with asthma, the majority of whom were male (57.37%) and Black (59.78%). The mean age at blood sample collection for BLL measurements among those with asthma was 23.19 months (SD=16.02). Among all children, 27.24% had a peak BLL of ≥ 3.5 µg/dl. Compared to children with BLL <1µg/dl, adjusted RR of asthma diagnosis for those with a BLL of 1.0 – 3.4 µg/dl was 1.89 (95% CI 1.55–2.31), while risk for those with a BLL ≥ 3.5 µg/dl was 1.94 (95% CI: 1.56-2.40). Adjusted RR were slightly higher for males than females. No significant association was observed between elevated BLLs and asthma severity. However, higher BLLs were significantly associated with increased frequency of asthma events.
Conclusion
Children with higher BLLs had an increased risk of asthma diagnosis. Importantly, associations were observed for children with BLLs below the current CDC-set action level. These findings emphasize the importance of addressing environmental lead exposure to mitigate asthma risk in children, even among children with low-level exposure.