title: The association between asthma and rhinitis is stable over time despite diverging trends in prevalence.
abstract: BACKGROUND
  Despite the well-known association between asthma and rhinitis, in Swedish adults the prevalence of rhinitis rose from 22% to 31% between 1990 and 2008 while asthma prevalence was unchanged. We tested whether the association of rhinitis with asthma was stable over time using the same population-based databases.
  
  
  METHODS
  Two surveys of adults (20-44 years) living in three regions of Sweden, carried out in 1990 (n = 8982) and 2008 (n = 9156) were compared. Identical questions regarding respiratory symptoms, asthma and rhinitis were used. Asthmatic wheeze: Wheeze with breathlessness apart from colds. Current asthma: Asthma attacks and/or asthma medication use.
  
  
  RESULTS
  Subjects with rhinitis had level time trends in asthmatic wheeze, current asthma and most nocturnal respiratory symptoms between 1990 and 2008, adjusted for age, sex, area and smoking. Any wheeze however decreased slightly. In never-smokers asthma symptoms were similarly associated with rhinitis in 1990 and 2008: any wheeze OR 4.0 vs. 4.4 (p = 0.339); asthmatic wheeze OR 6.0 vs. 5.9 (p = 0.937); and current asthma OR 9.6 vs. 7.7 (p = 0.213). In the whole population there were decreases in the asthma symptoms most closely associated to smoking, which decreased by half 1990-2008. Conversely current asthma, which was strongly associated with rhinitis and not with smoking, increased (p < 0.001).
  
  
  CONCLUSIONS
  The association of rhinitis with asthma was stable between 1990 and 2008. The pattern in the time trends of asthma outcomes strongly suggests that decreased smoking counterbalanced the driving effect of increased rhinitis on asthma prevalence. The findings illustrate the public health benefits of decreased smoking.
authors: Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, University of Gothenburg, Göteborg, Sweden. Electronic address: anders.bjerg@gu.se.
authors: Anders
authors: A
authors: Bjerg
authors: Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, University of Gothenburg, Göteborg, Sweden.
authors: Jonas
authors: J
authors: Eriksson
authors: Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden.
authors: Inga Sif
authors: IS
authors: Ólafsdóttir
authors: Experimental Asthma and Allergy Research, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors: Roelinde
authors: R
authors: Middelveld
authors: Department of Surgery, University of Umeå, Umeå, Sweden.
authors: Karl
authors: K
authors: Franklin
authors: Environmental and Occupational Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
authors: Bertil
authors: B
authors: Forsberg
authors: Unit of Lung and Allergy Research, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors: Kjell
authors: K
authors: Larsson
authors: Department of Public Health and Community Medicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
authors: Kjell
authors: K
authors: Torén
authors: Experimental Asthma and Allergy Research, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors: Sven-Erik
authors: SE
authors: Dahlén
authors: Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden.
authors: Christer
authors: C
authors: Janson
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D065631:Rhinitis, Allergic / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
keywords: Adults; Asthma; Epidemiology; Rhinitis; Smoking; Wheeze