Long-term fracture risk among children with asthma: a population-based study.
Fracture risk among patients diagnosed with asthma in childhood is greater in males and oral corticosteroid users, but most fractures are of the appendicular skeleton and may relate to impaired skeletal development.


BACKGROUND
There are no population-based data on fracture outcomes among the growing number of patients with asthma diagnosed in childhood.


METHODS
We conducted a population-based retrospective (historical) cohort study among 279 Rochester, Minnesota, residents who were <35 years of age (mean, 6.2 years) when first diagnosed with asthma. Fractures were ascertained by review of comprehensive community medical records, and cases were compared directly with age- and sex-matched controls in a stratified proportional hazards model. Risk factors for fractures among the asthma cases were assessed using Andersen-Gill time-to-fracture regression models.


RESULTS
During 6649 person-years of follow-up (median, 24.3 years/subject), 107 asthma patients experienced 189 fractures, for a crude fracture incidence rate of 2.8 per 100 person-years. The actuarially estimated cumulative fracture incidence after 20 years was 40% compared with 34% among controls (p = 0.122). There was no significant increase in overall fracture risk among cases compared to their age- and sex-matched controls (hazard ratio [HR], 1.3; 95% CI, 0.9-1.9), but males with asthma had a 2.6-fold greater risk of hand and finger fractures than control males. The independent predictors of overall fracture risk among the asthma patients included male gender (HR, 2.2; 95% CI, 1.5-3.2) and use of oral corticosteroids (HR, 2.0; 95% CI, 1.2-3.1) or anti-cholinergic agents (HR, 3.9; 95% CI, 1.5-10).


CONCLUSIONS
Rather than osteoporotic fractures of the axial skeleton, oral corticosteroid therapy was associated here with limb fractures, suggesting a relationship with impaired development of a biomechanically competent skeleton. Additional studies are needed to assess this possibility.
Melton
L Joseph
LJ
Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
Patel
Ashok
A
Achenbach
Sara J
SJ
Oberg
Ann L
AL
Yunginger
John W
JW
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000009:adverse effects / Q000627:therapeutic use; D000328:Adult; D000367:Age Factors; D018927:Anti-Asthmatic Agents / Q000009:adverse effects / Q000627:therapeutic use; D001249:Asthma / Q000150:complications* / Q000188:drug therapy; D001842:Bone and Bones / Q000293:injuries*; D002648:Child; D005260:Female; D050723:Fractures, Bone / Q000209:etiology*; D006801:Humans; D008297:Male; D018570:Risk Assessment; D012737:Sex Factors
D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents