NEWS Children who develop allergic sensitization (allergy antibodies) at an early age have a high risk of asthma and allergic rhinitis (inflammation of the mucous membranes of the nose) during school age. This is one of the results of a dissertation by Joakim Bunne at Umeå University.
Among school children in Norrbotten, allergic sensitization to airborne allergens occurs in 30% at the age of 8, a proportion that has increased since 1996 but remained stable between 2006 and 2017. The likelihood of developing asthma or allergic rhinitis during school age is very high among children who were sensitized at 8 years of age. On the other hand, the thesis did not see any association between sensitization and lung function, despite the fact that sensitization is related to asthma, which in turn is associated with poorer lung function.
Joakim Bunne, Department of Public Health and Clinical Medicine.
ImageJonas HanssonAsthma and allergic rhinitis are among the most common chronic diseases among children. Allergic sensitization, which can be measured with skin prick tests or blood tests for antibodies to allergens, is a strong risk factor for asthma and allergic rhinitis. It is known that the prevalence increases during childhood until young adulthood, but risk factors for sensitization are not as well studied as asthma. It is not known why some develop sensitization and others do not.
"The relationship between sensitisation and disease is also complicated by the fact that sensitisation occurs without disease, and vice versa. Furthermore, asthma is related to poorer lung function, and sensitization to asthma. On the other hand, few studies have investigated the relationship between sensitization and lung function independent of asthma," says Joakim Bunne, Department of Public Health and Clinical Medicine.
The OLIN studies have followed schoolchildren in Norrbotten from the age of 8 to 19, starting in 1996, when all children in grades 1 and 2 in Luleå and Kiruna were invited to questionnaires and skin prick tests. To investigate changes over time, new cohorts were investigated in 2006 and 2017 using the same methods. The focus of the thesis is allergic sensitization, and the results are based on data collected from all three child cohorts.
At 8 years of age, there is initially an increase in sensitization over time, from 21% to 30% between 1996 and 2006. The proportion remained unchanged in 2017. The difference seen between the first two groups persisted at age 12 years, when 30% and 41% were sensitized, respectively. This was driven by a larger new onset of cases in the second group, which has not been investigated in other studies. The reason for both the increase between the first two groups and the levelling off to the third is unknown, and is not explained by changes in the prevalence of investigated risk factors for sensitization.
The thesis also shows that age at onset of sensitization is important for the development of asthma and allergic rhinitis in school age. Those who were sensitized at age 8 had the highest risk of developing asthma and allergic rhinitis through age 19, and they were also sensitized to the highest number of allergens. The follow-up over time showed that those sensitized early had a high risk of asthma and allergic rhinitis during school age. Thus, it is unusual not to develop disease over time, something that is sometimes claimed for sensitized without disease. However, no association was seen between sensitization and lung function, despite the fact that asthma is related to poorer lung function and sensitization is a risk factor for asthma.
"Few studies have investigated the relationship between sensitisation and lung function independent of asthma, and the results support that sensitisation in itself does not affect lung function," says Joakim Bunne.
Joakim Bunne is a specialist in general medicine and a general practitioner at Hortlax health centre. He will be the first doctoral student in the OLIN studies to be included in the data, as a participant in the first child cohort.
The thesis
On Friday 22 March, Joakim Bunne, Department of Public Health and Clinical Medicine, defends his thesis entitled Allergic sensitization among schoolchildren in northern Sweden - Time trends, risk factors and relation to asthma, allergic rhinitis and lung function. The dissertation takes place at 09:00 in the Auditorium, Sunderby Hospital. Opponent is Associate Professor Caroline Nilsson, Karolinska Institutet
Electronic publication
Contact
Phone: +46 73 084 56 70
Mail: joakim.bunne@gmail.com