Peripheral single photon absorptiometry was used to measure forearm bone mineral density in 22 celiacs on gluten-free diet from childhood (male 14, female 8, age 13-20) and 29 untreated adult celiacs at diagnosis (male 5, female 24, age 18-56, 14 with subclinical disease), compared with healthy sex- and age-matched controls. Bone mineral density was similar in patients treated from childhood and their controls [(668.4 +/- 65.3 vs. 654.9 +/- 69.6 mg/cm2, (mean +/- SD)], but significantly lower in untreated patients than in their controls (598.3 +/- 83.1 vs 673.2 +/- 42.7 mg/cm2, p less than 0.001). It was also significantly lower in the 12 younger untreated celiacs (18-28 yr) versus controls (619.4 +/- 68.5 vs 669.1 +/- 39.3 mg/cm2, p less than 0.01). In the untreated women, but not their controls, a negative correlation (p less than 0.05) was observed between bone mineral density and age. Bone mineral density did not correlate with severity of clinical or biochemical abnormalities. These results suggest that bone derangements are common in celiacs diagnosed in adulthood, even if they never presented evident malabsorption symptoms, and emphasize the importance of early diagnosis and treatment.