Dental X-rays and the risk of intracranial meningioma: a population-based case-control study.
BACKGROUND
Ionizing radiation is a likely cause of intracranial meningioma. The authors determined whether the risk of intracranial meningioma was associated with past dental X-rays-specifically, posterior bitewings, full-mouth series, and lateral cephalometric and panoramic radiographs.


METHODS
The authors conducted a population-based case-control study of residents of King, Pierce, and Snohomish counties in western Washington State. Case patients (n = 200) had an incident intracranial meningioma that was confirmed histologically during life between January 1995 and June 1998. The authors used random-digit dialing and Medicare eligibility lists to identify two control subjects to be matched to each case patient based on age and gender. Exposures were determined during an in-person interview. The authors compared self-report and dental records in a subset of study participants.


RESULTS
Of the 4 dental X-ray procedures evaluated, only the full-mouth series (specifically, > or = 6 over a lifetime) was associated with a significantly increased risk of meningioma (odds ratio, 2.06; 95% confidence limits, 1.03-4.17). However, evidence for a dose-response relation was lacking (P for trend = 0.33). The risk was elevated with the aggregate number of full-mouth series in 10-year periods from approximately 15-40 years before diagnosis, with significant elevations in the 10-year periods beginning 22-30 years before diagnosis. The risks in these analyses were even greater when only women were considered.


CONCLUSIONS
Dental X-rays involving full-mouth series performed 15-40 years ago, when radiation exposure from full-mouth series was much greater than it is now, were associated with an increased risk of meningioma. The authors did not observe an increased risk with bitewings, lateral cephalometric, and panoramic radiographs.
Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA. wl@u.washington.edu
W T
WT
Longstreth
Leslie E
LE
Phillips
Mark
M
Drangsholt
Thomas D
TD
Koepsell
Brian S
BS
Custer
Jo-Ann
JA
Gehrels
Gerald
G
van Belle
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000209:etiology; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008579:Meningioma / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis* / Q000453:epidemiology*; D016017:Odds Ratio; D011159:Population Surveillance; D011379:Prognosis; D011861:Radiography, Dental / Q000009:adverse effects*; D012016:Reference Values; D018570:Risk Assessment; D017678:Sex Distribution