RT Journal Article SR Electronic T1 High but stable incidence of adult-onset asthma in northern Sweden over the last decades JF ERJ Open Research JO erjor FD European Respiratory Society SP 00262-2021 DO 10.1183/23120541.00262-2021 A1 Petri Räisänen A1 Helena Backman A1 Linnea Hedman A1 Martin Andersson A1 Caroline Stridsman A1 Hannu Kankaanranta A1 Pinja Ilmarinen A1 Heidi Andersen A1 Päivi Piirilä A1 Anne Lindberg A1 Bo Lundbäck A1 Eva Rönmark YR 2021 UL http://openres.ersjournals.com/content/early/2021/04/22/23120541.00262-2021.abstract AB Background The prevalence of asthma has increased both among children and adults during the latter half of the 20th century. The prevalence among adults is affected by the incidence of asthma in childhood but also in adulthood. Time trends in asthma incidence are poorly studied.Aim The aim was to study the incidence of adult-onset asthma from 1996–2006 and 2006–2016, and compare the risk factor patterns.Methods Within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, two randomly selected population-based samples in ages 20–69 years participated in postal questionnaire surveys about asthma in 1996 (n=7104, 85%) and 2006 (n=6165, 77%), respectively. A 10-year follow-up of the two cohorts with the same validated questionnaire was performed, and n=5709 and n=4552, respectively, responded. Different definitions of population at risk were used in the calculations of asthma incidence. The protocol followed a study performed 1986 to 1996 in the same area.Results The crude incidence rate of physician-diagnosed asthma was 4.4/1000/year (men 3.8, women 5.5) from 1996–2006, and 4.8/1000/year (men 3.7, women 6.2) from 2006–2016. When correcting for possible under-diagnosis at study entry, the incidence rate was 2.4/1000/year from 1996–2006 and 2.6/1000/year from 2006–2016. The incidence rates were similar across age groups. Allergic rhino-conjunctivitis was the main risk factor for incident asthma in both observation periods (risk ratios 2.4–2.6).Conclusions The incidence of adult-onset asthma has been stable over the last two decades, and on similar level since the 1980s. The high incidence contributes to the increase in asthma prevalence.FootnotesThis manuscript has recently been accepted for publication in the ERJ Open Research. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article.Conflict of interest: Dr. Räisänen has nothing to disclose.Conflict of interest: Dr. Backman reports personal fees from Boehringer Ingelheim, personal fees from AstraZeneca, outside the submitted work.Conflict of interest: Dr. Hedman has nothing to disclose.Conflict of interest: Dr. Andersson has nothing to disclose.Conflict of interest: Dr. Stridsman reports personal fees from AstraZenica, personal fees from Boehringer Ingelheim, personal fees from Novartis, outside the submitted work.Conflict of interest: H. Kankaanranta reports fees for lectures and consulting, and costs for attending an international congress from AstraZeneca, Boehringer Ingelheim and Orion Pharma; fees for consulting and lectures from Chiesi Pharma AB, Novartis and GlaxoSmithKline; fees for lectures from Mundipharma; and fees for consulting from SanofiGenzyme, all outside the submitted work.Conflict of interest: P. Ilmarinen reports a fee for a lecture from and will be an employee in March of GlaxoSmithKline, and reports fees for lectures from Mundipharma and AstraZeneca, and a fee for a lecture and for preparing presentation material from Novartis, outside the submitted work.Conflict of interest:Conflict of interest: Dr. Piirilä has nothing to disclose.Conflict of interest: A. Lindberg reports personal fees for lectures and an advisory board from Boehringer Ingelheim, personal fees for advisory boards from AstraZeneca and GlaxoSmithKline, and personal fees for lectures from Novartis, outside the submitted work.Conflict of interest: B. Lundbäck reports personal fees for lecturing and advisory meeting participation from Novartis, personal fees for advisory meeting participation from Sanofi, and a grant for a study on study on respiratory epidemiology from AstraZeneca, outside the submitted work.Conflict of interest: R. Rönmark reports grants from the Swedish Heart and Lung fundation, the Swedish Asthma and Allergy Foundation, Norrbotten county council, and ALF (a regional agreement between Umeå University, Västerbotten county council and Norrbotten county council), during the conduct of the study; and lecture fees from AstraZeneca, outside the submitted work.