Racial Differences in Bone Microarchitecture and Estimated Strength at the Distal Radius and Distal Tibia in Older Adolescent Girls: a Cross-Sectional Study

Abstract

Background Previous studies have demonstrated that an individual’s race and ethnicity are important determinants of their areal bone mineral density (aBMD), assessed by dual-energy x-ray absorptiometry. However, there are few data assessing the impact of race on bone microarchitecture and strength estimates, particularly in older adolescent girls and young adults. We hypothesized that bone microarchitecture and strength estimates would be superior in Blacks compared to White and Asian American adolescent girls and young adults of similar age based on reports of higher aBMD in Blacks. Methods We assessed BMD using DXA, bone microarchitecture at the distal radius and distal tibia using high resolution peripheral quantitative computed tomography (HRpQCT) and estimated measures of bone strength using micro-finite element analysis (FEA) in 35 White, 15 Asian-American and 10 Black girls 14–21 years. Results After controlling for height, most DXA measures of aBMD and aBMD Z-scores were higher in Black girls compared with Whites and Asian-Americans. HRpQCT and FEA showed that at the distal radius, Blacks had greater cortical perimeter, cortical area, trabecular thickness, trabecular BMD, estimated failure load and stiffness than the other two groups. For the distal tibia, trabecular number and BMD were higher in Blacks than Asian-Americans. Conclusions Particularly at the distal radius, adolescent and young adult White and Asian-American girls have less favourable bone microarchitecture and lower bone strength than Blacks, possibly explaining the lower risk of fracture seen in Blacks. Level of Evidence Level II

Risk of Stress Fracture Varies by Race/Ethnic Origin in a Cohort Study of 1.3 Million US Army Soldiers

“…Furthermore, peripheral quantitative computed tomography data indicate that black and Hispanic children have 10% to 37% greater estimated bone strength of the tibia and radius than white children, attributable to greater cortical bone density (2% to 5%) and bone area (7% to 18%) in Hispanic and black children compared with white children . Studies using high‐resolution peripheral computed tomography also confirm more favorable bone microarchitecture at the peripheral skeleton in adolescent black and Asian individuals compared with non‐Hispanic whites . Altogether, these patterns of racial and ethnic variations in BMD, bone microarchitecture, and bone strength that begin in childhood and track into adulthood likely contribute to race and ethnic differences in stress fracture risk found in the current study of US Army Soldiers.…”

“…Low areal bone mineral density (aBMD), tibial trabecular volumetric BMD (vBMD), and cortical area are associated with increased stress fracture risk among military personnel . Consistent with their lower risk of stress fracture, studies have routinely demonstrated higher BMD and more favorable bone microarchitecture among black individuals . For example, the National Health and Nutrition Examination Study (NHANES) reported that in older adults, non‐Hispanic blacks have the highest BMD values, non‐Hispanic whites the lowest BMD values, and Mexican Americans have BMD values between those of non‐Hispanic blacks and non‐Hispanic whites .…”

“…(3,(37)(38)(39)(40) Consistent with their lower risk of stress fracture, studies have routinely demonstrated higher BMD and more favorable bone microarchitecture among black individuals. (28,(41)(42)(43) For example, the National Health and Nutrition Examination Study (NHANES) reported that in older adults, non-Hispanic blacks have the highest BMD values, non-Hispanic whites the lowest BMD values, and Mexican Americans have BMD values between those of non-Hispanic blacks and non-Hispanic whites. (41) Blacks have also been shown to have greater cortical thickness at the proximal femur in older men (43) and greater cortical area and thickness at the tibia and radius in older women (28) when compared with their white counterparts.…”

“…The antecedents for these racial variations in bone properties and stress fracture risk appear rooted in puberty when racial differences in peak bone mass, bone density, and structure manifest. (42,(47)(48)(49)(50)(51)(52)(53)(54) For example, the Bone Mineral Density in Childhood Study examined more than 2000 healthy children (5 to 20 years of age) and found that BMD is higher at all skeletal sites in black compared with non-black children and young adults. (54) Furthermore, peripheral quantitative computed tomography data indicate that black and Hispanic children have 10% to 37% greater estimated bone strength of the tibia and radius than white children, attributable to greater cortical bone density (2% to 5%) and bone area (7% to 18%) in Hispanic and black children compared with white children.…”

Overexpression of GαS in Murine Osteoblasts In Vivo Leads to Increased Bone Mass and Decreased Bone Quality

“…Increased Gα S stimulates bone turnover in favor of bone formation; however, this also drastically reduces bone quality. As levels of Gα S in the human population are known to vary, they may contribute to currently unexplained variation in bone microarchitecture, mineral density, and strength . The HOM‐G S mice will allow us to assess the effects of catabolic and anabolic stimuli in the presence of increased Gα S and assess potential avenues for therapeutic intervention.…”