Subtypes of Adult-Onset Asthma at the Time of Diagnosis: A Latent Class Analysis.

INTRODUCTION

Only a few previous studies have investigated the subtypes of adult-onset asthma. No previous study has assessed whether these subtypes are different between men and women, or whether these subtypes have different risk factors.

METHODS

We applied latent class analyses to the Finnish Environment and Asthma Study population, including 520 new cases of adult-onset asthma. We formed subtypes separately between women and men and analyzed the following determinants as potential predictors for these subtypes: age, body mass index, smoking, and parental asthma.

RESULTS

Among women, the subtypes identified were: 1. , 2. , 3. , 4. , and 5. . Among men, the subtypes were: 1. , 2. , 3. , and 4. . Three of the subtypes were similar among women and men: , and . In addition, women had two distinct subtypes: , and . These subtypes had different risk factor profiles, e.g., heredity was important for and (RR for Both parents having asthma in Eosinophilic 3.55 (1.09 to 11.62)). Furthermore, smoking increased the risk of among women (RR for former smoking 2.21 (1.19 to 4.11)) and among men but had little influence on or Conclusion: This is an original investigation of the subtypes of adult-onset asthma identified at the time of diagnosis. These subtypes differ between women and men, and these subtypes have different risk factor profiles. These findings have both clinical and public health importance for the etiology, prognosis, and treatment of adult-onset asthma.