Associations between asthma status and radiologically confirmed fracture in children: a data-linkage study

AIM: World-wide, approximately 14% of children have prevalent asthma. As most bone accrual occurs in childhood, and data suggest a detrimental role in bone from asthma and/or medications, we investigated whether asthma was associated with radiologically confirmed fractures in a large cohort of children. METHODS: Data from the Barwon Asthma Study (2005), a population-based, cross-sectional survey of all children attending 91 primary schools in the Barwon Statistical Division, were linked to the Geelong Osteoporosis Study Fracture Grid (2006-2007), a fracture register encompassing the Barwon Statistical Division (n = 16 438; 50.5% boys; aged 3.5-13.6 years). Asthma, ascertained from parent-reported symptoms using the International Study of Asthma and Allergies in Childhood questionnaire, was categorised as: (i) recent wheeze; and number of (ii) recent wheezy episodes; (iii) doctor visits for wheeze symptoms; and (iv) doctor visits for asthma check-ups. Using logistic regression analyses, stratified by sex and adjusted for age and medication use, we determined whether asthma was associated with radiologically confirmed fractures. RESULTS: In total, 961 fractures were observed among 823 Barwon Asthma Study participants (5.9% of total sample; 61.1% boys). Recent wheeze and 1-3 recent wheezy episodes were associated with increased odds of fracture in boys (odds ratio (OR) 1.26, 95% confidence interval (CI) 1.03-1.55; OR 1.40, 95% CI 1.12-1.77, respectively), but not girls (OR 1.03, 95% CI 0.78-1.37; OR 0.67, 95% CI 0.38-1.19). Results were independent of age, and sustained after adjustment for medication. CONCLUSIONS: Independent of age, asthma was associated with fracture for boys, but not girls. There is an imperative for strategies to promote bone health among children with asthma.