Parental asthma and childhood asthma phenotypes: maternal associations with persistent asthma
Marianne Rørholt Grefslie, Siri Eldevik Håberg, Maria C Magnus, Tone K Omsland, Per MagnusBackground
Maternal asthma has been more strongly associated with asthma in offspring than paternal asthma, but the influence of parental asthma on distinct asthma phenotypes remains unclear.
Methods
We studied 16 055 children from the Norwegian Mother, Father and Child Cohort Study (MoBa). Parental asthma was reported at recruitment and classified as no parental asthma (reference), maternal asthma only, paternal asthma only or both parents with asthma. Offspring asthma was assessed at ages 3, 7 and 14 years through questionnaire-based parental reports, and four phenotypes were defined: never asthma, early-onset transient, early-onset persistent and late-onset asthma. Logistic regression was used to estimate associations between parental asthma status and offspring phenotypes, adjusting for sociodemographic, lifestyle and atopic factors, including atopic eczema and pollen/hay fever.
Results
Offspring asthma phenotypes were distributed as follows: never asthma 88.8%, early-onset transient asthma 3.3%, early-onset persistent asthma 2.7% and late-onset asthma 5.2%. Maternal asthma was associated with increased odds of all offspring asthma phenotypes: early-onset transient asthma (OR 2.09, 95% CI 1.52 to 2.88), early-onset persistent asthma (OR 3.47, 95% CI 2.56 to 4.71) and late-onset asthma (OR 2.18, 95% CI 1.69 to 2.81). Paternal asthma showed similar associations, although point estimates were generally smaller: early-onset transient asthma (OR 2.01, 95% CI 1.48 to 2.73), early-onset persistent asthma (OR 2.49, 95% CI 1.81 to 3.44) and late-onset asthma (OR 1.85, 95% CI 1.44 to 2.38). Asthma in both parents was most strongly associated with early-onset persistent asthma (OR 5.34, 95% CI 2.86 to 9.98), whereas associations with early-onset transient and late-onset asthma were smaller and accompanied by wider CIs. The overall pattern of associations was similar across analyses stratified by parental atopy.
Conclusions
Associations with maternal asthma were more pronounced than those with paternal asthma, particularly for early-onset persistent and late-onset phenotypes, although CIs overlapped for most comparisons. In contrast, early-onset transient asthma showed less differentiation by parental asthma status.