Diagnostic practice and the estimated prevalence of craniosynostosis in Colorado
B. W. Alderman, S. K. Fernbach, C. Greene, E. J. Mangione and S. W. Ferguson
Department of Epidemiology, University of Washington, Seattle, USA.
BACKGROUND: In the late 1980s, evidence of an epidemic of craniosynostosis
in Colorado included reports of clusters from selected high-altitude
communities and an investigation showing the high and rapidly rising rates
of surgically corrected synostosis. Some evidence suggested that local
diagnostic practice could account for the epidemic. OBJECTIVE: To determine
the contributions of any excess rates of disease occurrence, surgery-based
ascertainment, and diagnosis to the reported epidemic. DESIGN:
Population-based birth prevalence study with diagnostic evaluation.
SETTING: The Colorado Department of Health, April 15, 1986, to July 14,
1989. PATIENTS OR OTHER PARTICIPANTS: Children in the Craniosynostosis
Registry or state birth record files. MAIN OUTCOME MEASURES: Birth
prevalence was estimated from registry and birth record data; case
classification by suture type and malformation patterns were determined by
review of radiographs and medical records. RESULTS: The period birth
prevalence of radiographically confirmed nonsyndromic synostosis was 14.1
per 10,000 live births. Of a total of 605 children, 307 (51%) had definite
radiographic evidence of synostosis, for which the intrarater reliability
was good (except for the coronal suture on plain films) and the interrater
reliability was fair or good (except for the metopic suture on plain
films). Between the first and third years, case reports fell from 347 to
103. CONCLUSIONS: Diagnostic criteria strongly influenced the rate of
synostosis. The rate of radiographically confirmed synostosis was within
the range of published estimates. Low diagnostic thresholds, which changed
over time, created the semblance of a severe statewide epidemic and may
have obscured excess rates of disease at high altitude.