Lead poisoning and asthma: an examination of comorbidity

To determine the comorbidity of lead poisoning and asthma in urban children, and to examine associated clinical factors.

One-hundred-one patients at an inner-city clinic with blood lead levels (BLLs) of 25 microg/dL or higher (> or =1.2 micromol/L) (BLL25 group) were randomly selected from a tracking lead database and matched on age, sex, and primary language to 101 randomly selected patients with a first BLL recorded in the database of lower than 5 microg/dL (<0.2 micromol/L) (BLL5 group) and no subsequent BLLs of 10 microg/dL or higher (> or =0.5 micromol/L). Medical records were reviewed to determine diagnosis or symptoms of asthma or wheezing at any visit, immunization status, and number of visits. Analyses for matched pairs were conducted.

The BLL25 and BLL5 groups did not differ on age at diagnostic BLL (26.6 months vs 24.2 months), sex (54% male), or language (12% Spanish). The BLL25 and BLL5 groups had a similar number of subjects with a diagnosis of asthma (6% vs 11%; odds ratio, 0.5; 95% confidence interval, 0.2-1.6); 26% of BLL25 and 34% of BLL5 subjects had either a diagnosis or symptoms of asthma or wheezing (odds ratio, 0.7; 95% confidence interval, 0.4-1.3). Subjects with BLL25 were more likely to have delayed immunization and a first clinic visit when older than subjects with BLL5.

There was no increased likelihood of asthma diagnosis or symptoms among young children with lead poisoning. Children with lead poisoning also had delayed medical care. These data may help guide interventions aimed at preventing or reducing the impact of lead poisoning and asthma.