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- Almqvist, Linnea, 1987-
(författare)
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Asthma epidemiology : prognosis of asthma with onset in childhood and in adulthood
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aim: to update the knowledge on the epidemiology of asthma with onset in childhood and adulthood as well as examine the importance of risk factors in early childhood and clinical characteristics on the incidence and prognosis of asthma.Methods: The thesis is based on the epidemiological research program Obstructive Lung Disease in Northern Sweden (OLIN) studies. Pediatric cohort: recruited in 1996 (age 8y, n=3430, 97% of invited) and followed annually by questionnaire about asthma, allergy and risk factors until 19y and a postal questionnaire at 28y. Clinical examinations included skin prick tests (SPT at 8, 12 and 19y) and spirometry (19y). Adult cohort: 309 adults (age 20–60y) with asthma onset in the last 12 months were recruited 1995-99 and re-examined in 2012-14 (n=205). Structured interviews, spirometry and SPT were performed at recruitment and follow-up and bronchial hyperreactivity (BHR) at recruitment.Results: The asthma incidence rate was 10-13/1000/year in childhood and adolescence and 6/1000/year in young adulthood. Several risk factors in early life were associated with asthma onset in childhood, adolescence and young adulthood, e.g. family history of asthma, <3 months breastfeeding, rhinoconjunctivitis and positive SPT at 8y, while low birthweight, maternal smoking during pregnancy, severe respiratory infections and eczema were associated with onset in childhood and adolescence. Among those with asthma at 8y, 62% still had asthma at 28y and this was associated with positive SPT, rhinoconjunctivitis, severe respiratory infection in childhood, and bronchial hyperreactivity (BHR) in adolescence. Coexistence of asthma, rhinitis and eczema increased by age, especially among those with a positive SPT. However, having all three conditions was uncommon. In the 15y follow-up adult onset asthma, 89% had persistent asthma. Better lung function at recruitment and less severe BHR was associated with remission. Remission rate of adult onset asthma was <1% per year.Conclusion: The incidence of asthma was high during childhood and adolescence and then decreased in young adulthood. Factors in early life that were associated with incident asthma during childhood were still associated with the incidence in adult age. Among those with asthma onset by 8 years, 62%, still had asthma as young adults. The coexistence of asthma, rhinitis and eczema varied from 8 to 28y without following a specific pattern, only a small proportion reported having all three conditions. Remission of adult onset asthma was rare.
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| 2. |
- Bunne, Joakim, 1987-
(författare)
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Allergic sensitization among schoolchildren in northern Sweden : time trends, risk factors and relation to asthma, allergic rhinitis and lung function.
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Asthma and allergic rhinitis are common chronic diseases of childhood.Their prevalence has increased globally in the 20th century, with regionally diverging trends in recent years. Allergic sensitization (AS) is strongly associated with asthma and allergic rhinitis (AR), with similar trends over time and uncertainty of development in recent years. AS increases in childhood until young adulthood. Risk factors for AS are not as well characterized as for asthma and AR, and important aspects of the relation between AS and disease are not known. This includes why some sensitized children do not develop disease and how common this is in a longitudinal perspective. While many studies have assessed AS in the first years of life, fewer have focused on school age, and none have focused on the effect of age at onset of AS. Further, the association between AS and lung function is unknown.Aims: To assess time trends in prevalence, incidence and factors associated with AS in schoolchildren. Further, to assess the association between AS and asthma, allergic rhinitis and lung function, with special interest in age at onset of sensitization.Methods: Children in grades 1 and 2 (median age 8 years) in two municipalities in northern Sweden were invited to a questionnaire study of allergic diseases and skin prick tests to common aeroallergens in 1996. The cohort was reassessed at 12 and at 19 years also including spirometry. Identical methods were used to recruit a second and third cohort in 2006 and 2017.Results: The prevalence of AS at 8 years was 21% (1996), 30% (2006) and 30% (2017). Patterns of sensitization and risk factors for sensitization were similar. In the second cohort, the incidence between 8-12 years of 18% and prevalence of 41% at 12 years were higher than in the first cohort. Compared with later onset, sensitization ≤8 years was more strongly associated with asthma and allergic rhinitis at 19 years. AS was not independently associated with lung function at 19 years.Conclusions: In northern Sweden, the increase in allergic sensitization at age 8 years between 1996 and 2006 has halted in recent years. The increase between the first two cohorts was seen also at age 12 years. Age at onset of allergic sensitization impacts development of asthma and allergic rhinitis until 19 years. Despite an association with asthma, sensitization does not affect lung function at 19 years.
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| 3. |
- Hedman, Linnea, 1979-
(författare)
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Epidemiological studies of asthma and allergic diseases in teenagers : methodological aspects and tobacco use
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parental reports are often used in studies of asthma and allergic diseases in children. A change in respondent from parent to index subject usually occurs during adolescence. Little is known about the effects this change in method might have on the outcomes of a longitudinal study. Smoking is a major cause of respiratory symptoms among adults and environmental tobacco smoke (ETS) is a risk factor for asthma among children. Less is known about these associations among teenagers. In order to improve prevention of smoking, it is important to identify populations at risk of becoming smokers. The aim of this thesis were to 1) evaluate the methodological change from parental to self-completion of a questionnaire about asthma and allergic diseases, and 2) to study determinants for, and respiratory health effects of ETS and personal smoking in teenagers.In 1996, a longitudinal study of asthma and allergic diseases among schoolchildren started within the Obstructive Lung Disease in Northern Sweden (OLIN) studies. All children in first and second grades (aged 7-8 years) in three municipalities, Luleå, Kiruna and Piteå (n=3,525) were invited and 97% participated by parental completion of a questionnaire. The cohort has been followed with annual questionnaires until age 16-17 years and with high participation rates (>91%). From age 12-13 years, the teenagers were the respondents and questions about their tobacco use were included. In addition to the questionnaire completed by the teenagers at age 13-14 years, a questionnaire was also distributed to a random sample of 10% of the parents and 294 participated (84%). The parents and the teenagers reported a similar prevalence of asthma, respiratory symptoms, rhinitis, eczema and environmental factors. Two statistically significant differences were found: the teenagers reported a higher prevalence of wheezing during or after exercise (14% vs 8%, p<0.05), and having a dog in the home in the last 12 months (42% vs 29%, p<0.001). Answer agreement between parents and teenagers on questions about asthma was almost perfect with kappa values of 0.8-0.9. Corresponding kappa values for questions about respiratory symptoms and rhinitis were 0.3-0.6 and for eczema 0.5-0.6. Agreement about environmental factors varied from 0.2-0.9. Kappa values for parental smoking were 0.8-0.9. The risk factor pattern for allergic diseases was similar regardless of respondent, ie parent or teenager.The prevalence of smoking increased from 3% at 12-13 years to 6% at 14-15 years. Smoking was more common among girls, while the use of snus was more common among boys. Significant risk factors related to smoking among teenagers were smoking family members, female sex and living in an apartment. Having physician-diagnosed asthma did not prevent the teenagers from becoming smokers. Factors related to using snus were a smoking mother and male sex. Daily smokers aged 16-17 years (9%) reported a significantly higher prevalence of wheezing and physician-diagnosed asthma compared to non-smokers. There was a significant dose-response association with higher prevalence of wheeze among those who smoked ≥11 cigarettes per day compared to those who smoked ≤10 per day. In multivariate analyses, maternal environmental tobacco smoke exposure was a significant risk factor for ever wheeze and physician-diagnosed asthma at age 16-17 years, while daily smoking was a risk factor for current wheeze.In conclusion, the methodological change of questionnaire respondent from parent to index subject did not substantially alter the findings of this longitudinal study. There were significant sex differences in the tobacco use: smoking was more common among girls and snus was more common among boys. The most important factor related to tobacco use was presence of family members who smoke. Both maternal ETS exposure and personal smoking was associated with asthma and wheeze in adolescence. ETS was associated with lifetime symptoms but daily smoking was more strongly associated with current symptoms.
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