The early origins hypothesis with an emphasis on growth rate in the first year of life and asthma: a prospective study in Chile.
BACKGROUND
There is uncertainty about the impact of the programming hypothesis in terms of nutritional status at birth, rate of growth in the first year of life, length of gestation, breast feeding, and episodes of illness on asthma. An analysis was therefore carried out to test this hypothesis.


METHODS
Data were collected on 1232 children born between 1974 and 1978 in a semi-rural area of Chile. Measurements at birth and growth in the first year of life were obtained from a birth registry and clinical notes. Information on asthma was collected using the European Community Respiratory Health Survey questionnaire. Sensitisation to eight allergens and bronchial hyperresponsiveness (BHR) to methacholine were determined. All other information was obtained using a questionnaire. Polytomous logistic analyses were carried out to explore the association of factors at birth and during the first year of life with asthma symptoms, atopy, and BHR.


RESULTS
Weight and length gain in the first year were positively associated with wheeze (odds ratio (OR) 1.004, 95% CI 1.001 to 1.007 and OR 1.11, 95% CI 0.98 to 1.25, respectively). A higher body mass index (BMI) at birth was protective in subjects reporting both wheeze and waking with breathlessness (OR 0.54, 95% CI 0.35 to 0.84). Length rate in tertiles divided by length at birth in tertiles was related to asthma symptoms (OR 1.68, 95% CI 1.19 to 2.37). Most other assessments were not associated with asthma.


CONCLUSIONS
These results show promising but inconclusive evidence that a rapid rate of growth in length, especially in newborn infants of low length, might be involved in the aetiology of asthma.
Department of Public Health Sciences, King's College London, 5th Floor, Capital House, 42 Weston Street, London SE1 3QD, UK. roberto.rona@kcl.ac.uk
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Rona
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Smeeton
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Amigo
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D001249:Asthma / Q000453:epidemiology / Q000503:physiopathology*; D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D002677:Chile / Q000453:epidemiology; D005260:Female; D006128:Growth; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012423:Rural Health