Prevalence trends in respiratory symptoms and asthma in relation to smoking - two cross-sectional studies ten years apart among adults in northern Sweden

Abstract

BackgroundSmoking is considered to be the single most important preventable risk factor for respiratory symptoms. Estimating prevalence of respiratory symptoms is important since they most often precede a diagnosis of an obstructive airway disease, which places a major burden on the society. The aim of this study was to estimate prevalence trends of respiratory symptoms and asthma among Swedish adults, in relation to smoking habits. A further aim was to estimate the proportion of respiratory symptom and asthma prevalence attributable to smoking.MethodsData from two large-scale cross-sectional surveys among adults performed in northern Sweden in 1996 and 2006 were analysed. Identical methods and the same questionnaire were used in both surveys. The association between smoking, respiratory symptoms and asthma was analysed with multiple logistic regression analyses. Changes in prevalence of respiratory symptoms and asthma from 1996 to 2006 were expressed as odds ratios. Additionally, the population attributable risks of smoking were estimated.ResultsThe prevalence of most respiratory symptoms decreased significantly from 1996 to 2006. Longstanding cough decreased from 12.4 to 10.1%, sputum production from 19.0 to 15.0%, chronic productive cough from 7.3 to 6.2%, and recurrent wheeze from 13.4 to 12.0%. Any wheeze and asthmatic wheeze remained unchanged. This parallels to a decrease in smoking from 27.4 to 19.1%. In contrast, physician-diagnosed asthma increased from 9.4 to 11.6%. The patterns were similar after correction for confounders. All respiratory symptoms were highly associated with smoking, and the proportion of respiratory symptoms in the population attributed to smoking (PAR) ranged from 9.8 to 25.5%. In 2006, PAR of smoking was highest for recurrent wheeze (20.6%).ConclusionsIn conclusion, we found that respiratory symptoms, in particular symptoms common in bronchitis, decreased among adults in northern Sweden, parallel to a decrease in smoking from 1996 to 2006. In contrast, the prevalence of physician-diagnosed asthma increased during the same time-period. Up to one fourth of the respiratory symptom prevalence in the population was attributable to smoking.

Increased prevalence of allergic asthma from 1996 to 2006 and further to 2016—results from three population surveys

“…However, our efforts to control for differences in participation rates between surveys confirmed the main findings. COPD is an under‐diagnosed disease and it is likely that misclassification of COPD as asthma among the elderly occurred less frequently in 2016 than in the earlier surveys . This may explain why no increase in asthma was found in recent years in these ages.…”

“…The questionnaire was focused on respiratory symptoms, asthma, rhinitis and factors associated with the conditions including smoking. The exact phrasing of the core questions has been identical and is described elsewhere …”

Allergic sensitization is age-dependently associated with rhinitis, but less so with asthma

“…Reports of prevalence of asthma by age vary; however, most studies have found asthma to be most common among young adults. 20,25 Over the last 5 decades, we have observed an increased prevalence of both allergy and asthma, primarily in children. Importantly, those children have now become adults, and information on their maintained morbidity has previously been insufficiently reported.…”

“…In 2006, a random sample of the population of Norrbotten (n 5 7997; age, 20-69 years) was invited to participate in a postal questionnaire study. 20 In addition, another randomly selected population sample aged 30 to 84 years, which had participated in a similar questionnaire study in 1996, 20 was invited to a follow-up (n 5 7,004). Overall, 12,055 subjects (80% of invited) participated.…”

Species Delimitation and Phylogenetic Relationships in Ectobiid Cockroaches (Dictyoptera, Blattodea) from China

“…About 10 ectobiid species are important domiciliary pests and frequently found in human dwellings [42]. The most well known of these is Blattella germanica , which may pose certain health risks, including acting as a vector for pathogen transmission [43], and causing asthma [44,45]. We also performed molecular clock analyses to provide the first examination of the timeframe of evolution for ectobiid cockroaches.…”