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Sex Differences in Baseline Risk Factors for Asthma Between Early Adolescence and Young Adulthood

Kalm-Stephens P1, Nordvall L1, Janson C2, Malinovschi A3*, Alving K1*

1Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
2Department of Medical Sciences: Lung, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden
3Department of Medical Sciences: Clinical Physiology, Uppsala University, Uppsala, Sweden
*These authors contributed equally.

J Investig Allergol Clin Immunol 2023; Vol 33(1) : 21-29
doi: 10.18176/jiaci.0763

Background: Several studies have shown sex differences in the prevalence of asthma and an association with age. The aim of the present study was to prospectively investigate the development of asthma, wheeze, rhinitis, and allergic symptoms in adolescence and adulthood. We also aimed to determine whether sex modifies the association between baseline risk factors and incidence of asthma in early adulthood.
Methods: In the Screening Project Asthma in Schools (SPAIS) study, adolescents aged 12-15 years completed a standardized respiratory questionnaire (International Study of Asthma and Allergies in Childhood) and underwent measurements of fractional exhaled nitric oxide (FeNO) and lung function (FEV1) at baseline. Two follow-up assessments with similar questionnaires were performed after 4 and 16 years, with a total of 491 participants in all 3 examinations.
Results: The prevalence of asthma and wheeze were unchanged after 4 years but had increased after 16 years. However, the increase was significant only for females. The prevalence of rhinitis and allergy symptoms increased steadily, albeit with no differences between the sexes. The sex interaction analysis showed that higher FeNO (P=.01) and a family history of asthma (P=.02) increased the risk of incident asthma for males but not for females.
Conclusions: An increased prevalence of respiratory symptoms was seen primarily between late adolescence and young adulthood; the difference was significant for females but not for males. Allergic risk factors in early adolescence for incident asthma in early adulthood were confirmed in males but not in females. Awareness of these sex differences in the development of symptoms and of the associated risk factors is important in clinical practice.

Key words: Adolescents, Allergic symptoms, Epidemiology, Incidence, Lung function, Nitric oxide, Prevalence, Sex