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The Tucson Children's Respiratory Study. II. Lower respiratory tract illness in the first year of life
A L Wright1, L M Taussig, C G Ray
1Department of Pediatrics, University of Arizona, Tucson.
Insights
In infants, lower respiratory tract illnesses like bronchiolitis are common, often caused by respiratory syncytial virus. These childhood respiratory infections show consistent patterns over time.
Area of Science:
- Pediatrics
- Infectious Diseases
- Epidemiology
Background:
- Lower respiratory tract illnesses (LRTI) are a significant cause of morbidity in infants.
- Understanding the incidence, causative agents, and clinical presentation of LRTI is crucial for pediatric care.
Purpose of the Study:
- To describe the incidence and characteristics of LRTI in healthy infants during their first year of life.
- To identify the common infectious agents associated with these illnesses.
- To examine the relationship between identified agents, symptoms, and diagnoses.
Main Methods:
- Prospective study of 1,179 healthy infants enrolled in the Children's Respiratory Study.
- Data collection included clinical signs, symptoms, diagnoses, and microbiological cultures (viral, chlamydial, mycoplasmal) from nasopharyngeal and throat swabs.
- Follow-up for illnesses occurring within the first year of life.
Main Results:
- Cumulative incidence of LRTI was 32.88 per 100 children in the first year.
- Bronchiolitis accounted for 60% of the initial 348 LRTI cases.
- An infectious agent was identified in 66% of first illness specimens, with respiratory syncytial virus being the most common.
- Significant associations were found between specific agents and diagnoses (e.g., RSV with bronchiolitis, parainfluenza with croup).
- No association was observed between sex or ethnicity and illness experience.
Conclusions:
- LRTI, particularly bronchiolitis, is frequent in the first year of life and often linked to specific viral pathogens.
- The findings suggest that the patterns of childhood respiratory infections and their causative agents have remained relatively stable over recent decades.
- This study provides valuable epidemiological data on infant respiratory illnesses and their etiology.
Abstract:
Lower respiratory tract illnesses occurring during the first year of life in 1,179 healthy infants enrolled in the Children's Respiratory Study, Tucson, Arizona, are described. The children, who use the pediatricians of a health maintenance organization, were enrolled into the study between May 1980 and January 1984. Data were collected on signs, symptoms, and diagnosis for each illness; nasopharyngeal and throat swabs were collected at the acute visit for viral, chlamydial, and mycoplasmal cultures. The cumulative incidence of illness in the first year of life was 32.88 per 100 children. Of the 348 initial lower respiratory tract illnesses occurring in these infants, 60% were diagnosed as bronchiolitis. At least one infecting agent was identified in 66% of the specimens collected at the time of the first illness. Respiratory syncytial virus was the most common isolate; 12 other agents were also identified. There was a strong (p less than 0.0001) relation between agent identified, symptoms reported, and diagnosis; bronchiolitis was predominantly associated with respiratory syncytial virus and croup with parainfluenza viruses. Sex and ethnicity were unrelated to illness experience or to characteristics of the first illness. Lower respiratory tract illness occurrence in the Children's Respiratory Study appears to be similar to patterns observed elsewhere, suggesting that diagnoses (and infecting agents) have changed little over the past decades.