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Biomedical subjects

B G Kolnaar

Publications and source records attributed to B G Kolnaar.

5 recordsLinked to original sources
PubMed1997

Asymptomatic bronchial hyperresponsiveness in adolescents and young adults.

The clinical significance of asymptomatic bronchial hyperresponsiveness (BHR) is not well-known. The aim of this study was to explore, in a cross-sectional analysis, the characteristics of adolescent subjects with asymptomatic BHR, as compared to nonhyperresponsive subjects and those with symptomatic BHR. The subjects were selected by date of birth from the register of general practitioners. The hypothesis that both asymptomatic and symptomatic BHR are related to early childhood lower respiratory tract infections was also tested, in a historical cohort analysis. Respiratory morbidity was studied in early childhood and BHR in adolescence and young adulthood, in a population of 551 subjects aged 10-23 yrs. Morbidity had been recorded prospectively since birth in the general practice. Data on chronic respiratory symptoms, smoking behaviour, airways obstruction, BHR and allergy were collected during this investigation. BHR was present in 42% of the subjects, of which 70% were asymptomatic. The occurrence of symptomatic BHR was related to acute bronchitis in early childhood, allergy, airways obstruction and recent asthma, acute bronchitis and hay fever; whereas, asymptomatic BHR was not. Characteristics of subjects with asymptomatic BHR did not differ significantly from those without BHR, with respect to these factors. We conclude that asymptomatic bronchial hyperresponsiveness in adolescence and young adulthood is not related to lower respiratory infections in early childhood. Furthermore, subjects with asymptomatic bronchial hyperresponsiveness have similar characteristics to those without bronchial hyperresponsiveness, but differ strongly from subjects with symptomatic hyperresponsiveness. Asymptomatic bronchial hyperresponsiveness may not be the link between early childhood lower respiratory morbidity and asthma in later life, nor a risk factor for later asthma.

Acute Disease↗
PubMed1995

The relationship between respiratory symptoms and bronchial hyperresponsiveness in a population-based sample of adolescents and young adults.

OBJECTIVES: to study the relationship between chronic respiratory symptoms and bronchial hyperresponsiveness (BHR) in adolescence and young adulthood and to assess the possible predictive value of these symptoms for BHR. METHODS: a cross-sectional analysis: in a population sample of 551 subjects aged 10-23 years, data collected with a standardized questionnaire on respiratory symptoms were compared with the results of a histamine challenge test. RESULTS: 43% of the subjects reported one or more chronic respiratory symptoms; of these subjects 54% did not show BHR. Forty-two per cent of the subjects had a PC20 < or = 8.0 mg ml-1 histamine, of which 53% reported no chronic respiratory symptoms. Wheezing and breathlessness were related to the level of BHR, but only 'breathless when walking on the flat' was independently related to BHR; however, its predicted value for BHR was negligible. CONCLUSIONS: in adolescents and young adults the relationship between chronic respiratory symptoms and BHR is incomplete. A standardized questionnaire on respiratory symptoms does not provide adequate information to discriminate between those with and without BHR.

Adolescent↗
PubMed1994

The clustering of respiratory diseases in early childhood.

BACKGROUND: It has been suggested that early childhood respiratory morbidity is related to asthma and chronic bronchitis in later life. To understand these relations, it is necessary to know how early childhood respiratory diseases are distributed, interrelated, and clustered. This study analyzed the distribution, interrelations, and the clustering of early childhood respiratory morbidity. METHODS: We prospectively collected data of episodes of respiratory illness among 1140 children in the first five years of life, in family practice. To determine if the occurrence of respiratory illness was randomly distributed, we compared the frequency of respiratory illness to random Poisson distribution. We used factor analysis to determine if respiratory illnesses occurred in clusters or patterns according to type of illness. RESULTS: Five percent of subjects never presented a respiratory disease, and 53% presented at least six episodes. The episodes of each illness were not randomly distributed, and most conditions were associated with each other. Factor analysis showed that asthma, acute bronchitis, and pneumonia formed one cluster, and tonsillitis, otitis media, and common cold another cluster. CONCLUSIONS: Early childhood respiratory morbidity is unevenly distributed, but a clear-cut group of children with a much higher rate of more severe respiratory morbidity than other children could not be distinguished. Both upper and lower respiratory tract illnesses show clustering. In research on the long-term prognosis of early childhood respiratory morbidity, this morbidity may best be grouped into the categories identified in this research.

Child, Preschool↗
PubMed1994

Asthma in adolescents and young adults: relationship with early childhood respiratory morbidity.

AIM: This study was undertaken to examine the relationship between respiratory illness in early childhood and asthma in adolescence and young adulthood (age group 10-23 years). METHOD: The study population comprised 277 boys and 274 girls, born between 1967 and 1978 and registered from their birth to the year of study (1989) on the practice lists of the four general practices taking part in the continuous morbidity registration project (CMR) at the University of Nijmegen in the Netherlands. Details of all episodes of respiratory morbidity presented in the first five years of life and registered in the project were collected together with data on current respiratory status determined by means of a questionnaire on respiratory symptoms, spirometry and a histamine-challenge test. RESULTS: Sixteen per cent of the study group were diagnosed as having asthma. Only asthma and acute bronchitis in early childhood were significantly associated with asthma at age 10-23 years. CONCLUSION: Asthma in adolescence and young adulthood is related to asthma and acute bronchitis in early childhood. This study supports the view that this could be a causal relationship although an alternative explanation could be misclassification. The results provide no indication that upper respiratory tract infections are associated with the development of asthma in adolescence or young adulthood.

Adolescent↗