[Correlation of bone mineral density of the mandibular angle, hand and total body in 839 healthy individuals aged from 5 to 18 years].

OBJECTIVES: To investigate the correlation of bone mineral density (BMD) of mandibular angle, hand and total body in healthy individuals aged from 5 to 18 years. METHODS: Eight hundred and thirty-nine healthy individuals from 5 to 18 years old (422 males, 417 females) in 5 primary and secondary schools in Guangzhou were divided into 14 age groups. Dual energy X-ray absorptiometry (DXA) was used to measure the BMD of mandibular angle, hand and total body. The data were statistically analyzed using Pearson correlation analysis. RESULTS: The BMD of mandibular angle increased with age. In females, the BMD of mandibular angle increased quickly from 12 to 16 years old, and its increasing rate gradually slowed down after 16 years old. In males, the BMD of mandibular angle increased quickly after 14 years old, and its increase had not been stopped until 18 years old. Females in 12, 13, 14, 15, 16, 17-year-old group had significantly higher mandibular angle BMD [(0.95 ± 0.19), (1.01 ± 0.17), (1.11 ± 0.17), (1.25 ± 0.13), (1.28 ± 0.14), (1.30 ± 0.13) g/cm(2)] than males in the age-matched group (P < 0.05). There was no significant difference between mandibular angle BMD in males and in females at the age of 18, and from 5 to 11 years old (P > 0.05). For males, the mandibular angle BMD was highly correlated with age (r = 0.696, P < 0.001), hand BMD (r = 0.779, P < 0.001) and total body BMD (r = 0.831, P < 0.001). For females, the mandibular angle BMD was highly correlated with age (r = 0.795, P < 0.001), hand BMD (r = 0.839, P < 0.001) and total body BMD (r = 0.872, P < 0.001). CONCLUSIONS: The mandibular angle BMD in healthy individuals from 5 to 18 years old increased with age. The mandibular angle BMD was closely related to hand BMD and total body BMD.