The relationship of eosinophilia and positive skin test reactivity to respiratory symptom prevalence in a community-based population study

We studied the relationship of the prevalence of a variety of respiratory symptoms to positive skin test reactivity (skin test index ≥3) and/or eosinophilia (≥275 eosinophilic cells per cubic millimeter of blood) in a community-based population sample (N=2805), adjusting for age, gender, area of residence, and cigarette smoking. We considered subjects with neither positive skin test reactivity nor eosinophilia to be the reference group. Positive skin test reactivity without eosinophilia (N=487; 17.3%) was significantly associated with persistent wheeze (odds ratio value (OR)=1.6; 95% confidence interval of the odds ratio value (CI)=1.0 to 2.6) and with asthmatic attacks (OR=3.2; CI=2.0 to 5.3). Positive skin test reactivity in combination with eosinophilia (N=92; 3.3%) was also significantly associated with persistent wheeze (OR=2.7; CI=1.2 to 6.0) and with asthmatic attacks (OR=10.4; CI=5.3 to 20.2), however, with a stronger association than in subjects with positive skin test reactivity alone. Finally, eosinophilia without positive skin test reactivity (N=170; 6.1%) was significantly associated with chronic cough (OR=1.8; CI=1.2 to 2.7), bronchitis episodes (OR=2.1; CI=1.4 to 3.2), dyspnea grade ≥III (OR=1.7; CI=1.0 to 2.8), and asthmatic attacks (OR=3.0; CI=1.5 to 6.6). In conclusion, positive skin test reactivity, eosinophilia, and their combination have different patterns and strength of association with respiratory symptom prevalence and thus may enhance the information on the risk of these disorders.