How Asthma Affects Individuals of Different Ages
Asthma manifests with distinct age-dependent patterns: children under 3 years who develop symptoms experience the most significant lung function deficits by age 6, while adults face accelerated lung function decline and higher mortality risk, with sex differences reversing at puberty when males "outgrow" disease more frequently than females who develop more severe, persistent disease. 1
Early Childhood (Birth to 3 Years)
Critical window for lung development impact:
40% of all children have sustained wheezing illness in the first year of life, with 20% still wheezing at 3 years and 6 years of age. 1
Children whose asthma symptoms begin before 3 years of age experience significant, irreversible deficits in lung growth that occur by 6 years of age. 1 This represents the most critical period for long-term morbidity.
Males develop asthma 2 to 4 times more frequently than females in the first 3 years of life. 1
Diagnosis in children under 2 years is particularly challenging and relies almost entirely on symptom patterns, with recurrent wheeze often associated with viral infections. 2
Predictive factors for persistent disease:
Parental history shows strong genetic influence: 80% of children with two asthmatic parents develop disease compared with 40% with one asthmatic parent and 10% with no asthmatic parents. 1
Risk factors for persistent asthma in children under 3 years with >3 wheezing episodes include: physician-diagnosed atopic dermatitis/eczema OR parental history of asthma, OR two of three features (peripheral blood eosinophilia, wheezing apart from colds, physician-diagnosed allergic rhinitis). 1
School Age Children (3 to 12 Years)
More favorable prognosis with age-appropriate onset:
Children whose asthma symptoms begin after 3 years of age do NOT experience deficits in lung function. 1
Children aged 5-12 years with mild or moderate persistent asthma do not experience deficits in lung function growth through age 17, regardless of symptom levels or treatment received. 1
Most children with well-controlled asthma will experience significant improvement or complete resolution of symptoms during adolescence. 3
Recurrent wheeze, cough and breathing difficulty are key symptoms, with recurrent reported wheeze or wheeze on auscultation being the most important symptom. 1
Children with chronic cough (>4 weeks) as the only symptom are unlikely to have asthma. 1
Adolescence and Sex Transition (10+ Years)
Critical period for sex-based divergence:
By 10 years of age, prevalence becomes equal between sexes, but females become more likely to have disease persist, especially if present after puberty. 1
Females are more likely to die and/or be hospitalized than males after age 10. 1
Male children are more likely to "grow out" of asthma during transition to adulthood. 3
Female sex is a risk factor for persistence of asthma symptoms into adulthood. 3
The reversal of sex difference in prevalence occurs around puberty, suggesting sex hormones may play a role in asthma etiology. 4
Young Adulthood
Emerging risk factors and occupational concerns:
Smoking interacts with airway responsiveness and is associated with higher likelihood of new onset (or recrudescent) asthma in adulthood. 1
Symptoms, airway responsiveness, eosinophilia, and smoking reduce maximally attained levels of lung function in this age group. 1
Workplace exposures are responsible for 15-25% of asthma in adults. 1
Adult asthma is more common in women, contrasting with childhood male predominance. 4
Adults
Progressive disease with higher morbidity and mortality:
Accelerated loss of lung function occurs in adults with asthma, with the degree of persistent airflow obstruction correlating with both severity and duration of disease. 1
While asthma incidence and prevalence are higher in children, morbidity and mortality are higher in adults. 4
Adult asthma may accelerate lung function decline and increase risk of fixed airflow obstruction, with early onset asthma having greater effect than late onset asthma. 4
In adults, 30-50% will forget they had asthma diagnosis or wheeze symptoms 3 years earlier, making it difficult to determine if disease is truly incident or recurrence of symptoms. 1
Critical Clinical Implications by Age
For children <3 years with symptoms:
This represents the most promising target for interventions to prevent lung function deficits and severe symptoms later in life. 1
However, distinguish this group from the majority who wheeze before 3 years and experience no symptoms after 6 years. 1
For school-age children:
- Focus on symptom control and quality of life, as lung function trajectory is generally preserved with appropriate treatment. 1
For adolescents and adults: