Asthma is not a frozen state. A young child can have asthma-like symptoms that disappear, persist or change as the child grows — and the same family can contain very different trajectories.
Longitudinal twin research shows why “the cause” does not have to be one thing. In a very large Dutch twin cohort, persistence from asthma-like symptoms at age three to asthma at age seven was strongly linked to shared genetic liability. In a Puerto Rican infant twin cohort, the balance between shared environment and genetic effects looked different at ages one and three.
Quick answer
If asthma changes over time, does its cause change too?
Not necessarily in a simple way. Longitudinal twin studies show that stable inherited susceptibility can contribute to persistence while environmental contributions and their relative importance can differ by age and phenotype.
Key takeaways
- In 21,541 Dutch twin pairs, persistence from asthma-like symptoms at age three to asthma at age seven was strongly linked to shared genetic liability in the model.
- In a Puerto Rican twin cohort, shared environment contributed more to some asthma phenotypes at age one while genetic effects were larger at age three.
- In 34,782 Danish twins, genetic factors explained 34% and environmental factors 66% of variation in age at asthma onset.
- Different asthma phenotypes and ages should not be treated as the same statistical trait.
Why one snapshot is not enough
Asthma-like symptoms in preschool children are not the same phenotype as school-age asthma or age at onset in adults. Longitudinal data allow persistence to be separated from change.
Persistence can carry a stable genetic signal
The Netherlands Twin Register followed 21,541 twin pairs from age three to seven. High persistence between asthma-like symptoms and later asthma was explained largely by shared genetic liability in the statistical model.
Environment can still matter differently at different ages
In a longitudinal Puerto Rican infant-twin study, shared environmental effects dominated some phenotypes at age one while genetic effects were larger at age three. A separate Danish study showed that variation in age at asthma onset also had both genetic and environmental components.
That does not identify any single exposure, stressor or life event as the cause of a particular person's asthma.
Clinical boundary
TwinPare Research describes population evidence. It does not predict asthma onset, attacks or medication needs from twin status, stress or environmental data.
Source notes
The sources have been verified and editorially reviewed for this article. The limitations below show which level of conclusion the sources support.
- [asthma-longitudinal-twins-2022] Persistence of parental-reported asthma at early ages: A longitudinal twin study Elise M. A. Slob et al.. Pediatric Allergy and Immunology, 2022. Evidence type: Large longitudinal childhood twin study Limitation: In 21,541 Netherlands Twin Register pairs, persistence from asthma-like symptoms at age 3 to asthma at age 7 was strongly associated with shared genetic liability in the fitted model. Parental-reported childhood phenotypes are not personal prediction tools. PubMed PMC DOI
- [asthma-puerto-rico-twins-2013] A twin study of early-childhood asthma in Puerto Ricans Supinda Bunyavanich; Judy L. Silberg; Jessica Lasky-Su; Nathan A. Gillespie; Nancy E. Lange; Glorisa Canino; Juan C. Celedón. PLoS ONE, 2013. Evidence type: Longitudinal Puerto Rican infant twin study Limitation: Shared environmental effects dominated some asthma phenotypes at age 1 while genetic effects were larger at age 3 in this Puerto Rican twin cohort. Results are age-, phenotype- and population-specific. PubMed PMC DOI
- [asthma-age-onset-twins-2010] Genetic influence on the age at onset of asthma: a twin study Simon Francis Thomsen; David Lorenzo Duffy; Kirsten Ohm Kyvik; Vibeke Backer. Journal of Allergy and Clinical Immunology, 2010. Evidence type: Large Danish twin study of asthma age at onset Limitation: In 34,782 Danish twins, genetic factors explained 34% and environmental factors 66% of variation in age at asthma onset. Age-at-onset variation is not the same phenotype as asthma liability. PubMed DOI
- [asthma-risk-review-2025] Genetic and environmental risk factors for asthma: towards prevention Gerard H. Koppelman et al.. The Lancet Respiratory Medicine, 2025. Evidence type: Current peer-reviewed asthma genetics and environment review Limitation: Current review describing asthma as heterogeneous and shaped by multiple genetic, environmental, social and lifestyle factors and their interaction across the life course. It is not a personal prevention prescription. PubMed DOI
Editorial source review
This section shows how the article's key factual claims are linked to the source.
Phrasings that require caution
- Do not convert asthma heritability into a personal risk percentage.
- Do not diagnose asthma from symptoms or family/twin status.
- Do not recommend starting, stopping or changing asthma medication.
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