311:
Impact of asthma control on susceptibility to ambient air pollution among African American teens with asthma
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Michelle L. Hernandez, MD FAAAAI, Radhika Dhingra, PhD, Allison J. Burbank, MD, Krista Todoric, MD, Ceila Loughlin, MD, Marcia Frye, MD, Kelly E Duncan, PhD, Carole Robinette, MS, Katherine H Mills, BA, Robert Devlin, PhD, David B. Peden, MD MS FAAAAI, David Diaz Sanchez, PhD
RATIONALE: Despite overall improvements in air quality, exposure to ambient air pollution continues to cause asthma exacerbations. Having poorly controlled asthma increases risk of future asthma exacerbations; African-American teens are at high risk of having poorly controlled asthma. We hypothesized that having poorly controlled asthma increases susceptibility to ambient air pollution among African-American teens.

METHODS: This was a prospective observational study of 23 African-American teens with persistent asthma requiring controller therapies ages 12-17 followed at a subspecialty clinic. Participants completed questionnaires, performed spirometry, and underwent a history and physical exam at each of the six study visits over an 8-week period. At the baseline visit, study physicians classified participants’ asthma as “well-controlled” or “not-well controlled” in accordance with NHLBI guidelines. A linear mixed effects model was used to evaluate the relationship of each outcome to ambient ozone concentrations at each visit and in prior days.

RESULTS: At the baseline visit, 14/23 participants had well-controlled asthma. After controlling for particulate matter exposure, an increase in ozone levels was associated with decrements of 2.7% in FVC (p=0.02) and of 2.5% in FEV1 (p=0.07) per interquartile range (0.017 ppm) on the day of exam. Likewise, an increase in ozone levels was associated with a 0.93 increase in the total Asthma Control Questionnaire score (p<0.001). There was no effect modification by baseline level of asthma control.

CONCLUSIONS: Among African-American teens exposed to ozone levels below the National Ambient Air Quality Standard, having “well-controlled” asthma was not sufficient to protect against the pulmonary health effects of ambient air pollution.