*3.1. Study Participants*

Asthma patients and control subjects were well matched according to the demographic variables, including age, sex, body mass index (BMI), and the area of residence, i.e., rural vs. urban area (Table 1). Likewise, the prevalence of other chronic comorbidities (such as arterial hypertension or diabetes mellitus) was similar. Finally, all study participants were current nonsmokers (>5 years).

**Table 1.** Demographic characteristics and comorbidities in asthmatic patients and control individuals.


Categorical variables are presented as *n*-numbers (percentages); continuous variables are presented as median and interquartile range, or mean and standard deviation, as appropriate.
