Respiratory symptoms and their determinants in the general Spanish population: changes over 20 years

Background Few large epidemiological studies have analysed the prevalence of respiratory symptoms and their determinants in the general adult population. We investigated the prevalence and determinants of respiratory symptoms and compared their prevalence with that of two previous studies conducted in 1999 and 2009. Method EPISCAN II was a multicentre, cross-sectional, population-based epidemiological study in individuals older than 40 years. Results A total of 9092 individuals were included. Up to 47.5% reported at least one respiratory symptom, being more frequent in women than in men (49.4% versus 45.5%, p=0.0002) and with wheezing being the most frequent (33.7%) followed by dyspnoea (26.8%). The presence of any symptom was associated with female sex, higher body mass index (BMI), lower forced expiratory volume in 1 s (FEV1 % pred), reduced physical activity, a higher Charlson index and the presence of anxiety and depression. Smoking was also significantly associated with having at least one respiratory symptom in a dose-response fashion (OR: 1.415, 1.916, 2.192 and 2.987 for 0-10, 10-20, 20-30 and >30 pack-years, respectively, all p<0.0001). The prevalence of symptoms remained quite similar over the last 20 years (wheezing 40%, 36% and 33.7% and dyspnoea 10.4%, 9.9% and 13.1% in 1999, 2009 and 2019, respectively). Conclusions Approximately half of the adult Spanish population have respiratory symptoms and this prevalence has remained quite stable over the last 20 years. Smoking remains the main factor associated with respiratory symptoms, but female sex, comorbidities, high BMI and low FEV1 and low physical activity are also significantly associated with respiratory symptoms.