Bone mineral acquisition in healthy Asian, Hispanic, black, and Caucasian youth: A longitudinal study

Ethnic and gender differences in bone mineral acquisition were examined in a longitudinal study of 423 healthy Asian, black, Hispanic, and white males and females (aged 9-25 yr). Bone mass of the spine, femoral neck, total hi p, and whole body was measured annually for up to 4 yr by dual energy x-ray absorptiometry. Age-adjusted mean bone mineral curves for areal (BMD) and volumetric (BMAD) bone mineral density were compared for the 4 ethnic group s. Consistent differences in areal and volumetric bone density were observe d only between black and nonblack subjects. Among females, blacks had great er mean levels of BMD and BMAD at all skeletal sites. Differences among Asi ans, Hispanics, and white females were significant for femoral neck BMD, wh ole body BMD, and whole body bone mineral content/height ratio, for which A sians had significantly lower values; femoral neck BMAD in Asian and white females was lower than that in Hispanics. Like the females, black males had consistently greater mean values than nonblacks for all BMD and BMAD measu rements. A few differences were also observed among nonblack male subjects. Whites had greater mean total hip BMD, whole body BMD, and whole body bone mineral content/height ratio than Asian and Hispanic males; Hispanics had lower spine BMD than white and Asian males. The tempo of gains in BMD varie d by gender and skeletal site. In females, total hip, spine, and whole body BMD reached a plateau at 14.1, 15.7, and 16.4 yr, respectively. For males, gains in BMD leveled off at 15.7 yr for total hip and at age 17.6 yr for s pine and whole body. Black and Asian females and Asian males tended to reac h a plateau in BMD earlier than the other ethnic groups. The use of gender- and ethnic-specific standards is recommended when interpreting pediatric b one densitometry data.