Air quality improvement and the prevalence of frequent ear infections in children.

OBJECTIVE

To determine whether air quality influences the prevalence of pediatric frequent ear infections and respiratory allergy.

STUDY DESIGN

Case-control study.

SETTING

Academic medical center.

SUBJECTS AND METHODS

The National Health Interview Survey child sample for the calendar years 1997 through 2006 was analyzed, extracting 12-month prevalence data for the following three disease conditions: frequent (>/=3 within 12 months) ear infections, respiratory allergy, and seizures (nonrespiratory control condition). Based on information from the Environmental Protection Agency, yearly historical data for the air quality criteria pollutants carbon monoxide, nitrous dioxide, sulfur dioxide, and particulate matter were tabulated. Graphical and linear regression analyses were conducted to determine the influence of air quality on each of the disease conditions.

RESULTS

A total of 126,060 children were studied (51.4% male, mean age 8.6 yrs). Overall, the 12-month prevalence for three or more ear infections, respiratory allergy, and seizures was 6.6%, 11.7%, and 0.7%, respectively. Air quality steadily improved over the study period. Statistically significant positive regression coefficients were obtained for each of the criteria pollutants with ear infections (all P < 0.001), with regression coefficients ranging from 0.007 (particulate matter) to 11.2 (sulfur dioxide). For respiratory allergies, nonstatistically significant regression coefficients for the criteria pollutants were obtained (range <0.001-0.379, all P > or = 0.409). For the nonrespiratory condition seizures, nonsignificant regression coefficients were again identified (all P > or = 0.404).

CONCLUSIONS

Better air quality is significantly associated with lower prevalence of pediatric frequent ear infections but is not associated with the prevalence of pediatric respiratory allergy. Improvements in air quality may be implicated in the decreased rates of pediatric ear infections over time.