BackgroundThe prevalence of asthma in Taiwan was increasing in the past 30 years, causing a great impact on adolescent health. This study aimed to investigate the current prevalence, impact, and associated factors of asthma in Taiwanese adolescents. Material and methodsParents or guardians provided passive consent at home prior to the survey. Adolescents aged 13–14 years completed a questionnaire survey in 2017 in Taipei, Taiwan. The prevalence, impact, and associated factors of asthma were analyzed. We also compared the asthma prevalence with the prevalence in 1995 and 2001. ResultsWe analyzed 3474 validated questionnaires. The prevalence of physician-diagnosed asthma was 12.4%. The prevalence of current wheezing was 9.2% in 2017, which was 5.2% in 1995 and 7.0% in 2001. 3.3% of 13–14-year-old adolescents had severe asthma symptoms. Asthma significantly impacted the lives of adolescents. Of the students with asthma, 10.9% had school absenteeism, 16.5% urgently needed to see a doctor, 9.5% went to the emergency department, and 3.5% were admitted to hospitals within the preceding 12 months. The associated factors for physician-diagnosed asthma in Taiwanese adolescents were male (prevalence ratio [PR], 1.38; 95% confidence interval [CI], 1.05–1.83; p = 0.02), maternal history of asthma (PR, 2.61; 95% CI, 1.69–4.02; p < 0.01), and recent paracetamol use at least once per month (PR, 2.60; 95% CI, 1.24–5.42; p = 0.01). The associated factors for school absenteeism were nocturnal cough (PR, 1.99; 95% CI, 1.16–3.41; p = 0.01), current wheezing (PR, 7.52; 95% CI, 4.39–12.9; p < 0.01), and recent paracetamol use (at least once per month, PR, 3.16; 95% CI, 1.10–9.06; p = 0.03; at least once per year, PR, 2.19; 95% CI, 1.25–3.83; p < 0.01). ConclusionsThe prevalence of physician-diagnosed asthma was 12.4%. Asthma substantially impacted the lives of adolescents. Reducing nocturnal cough, wheezing frequency, and paracetamol usage might help decrease school absenteeism.