Volumetric bone mineral density (vBMD), bone structure, and structural geometry among rural South Indian, US Caucasian, and Afro-Caribbean older men

Abstract

SummaryPeripheral quantitative computed tomography (pQCT) provides biomechanical estimates of bone strength. Rural South Indian men have reduced biomechanical indices of bone strength compared to US Caucasian and Afro-Caribbean men. This suggests an underlying higher risk of osteoporotic fractures and greater future fracture burden among the rural South Indian men.IntroductionGeographical and racial comparisons of bone mineral density (BMD) have largely focused on DXA measures of areal BMD. In contrast, peripheral quantitative computed tomography (pQCT) measures volumetric BMD (vBMD), bone structural geometry and provides estimates of biomechanical strength. To further understand potential geographical and racial differences in skeletal health, we compared pQCT measures among US Caucasian, Afro-Caribbean, and rural South Indian men.MethodsWe studied men aged ≥ 60 years enrolled in the Mobility and Independent Living among Elders Study (MILES) in rural south India (N = 245), Osteoporotic Fractures in Men Study (MrOS) in the US (N = 1148), and the Tobago Bone Health Study (N = 828).ResultsThe BMI (kg/m2) of rural South Indian men (21.6) was significantly lower compared to the US Caucasians (28) and Afro-Caribbean men (26.9). Adjusting for age, height, body weight, and grip strength; rural South Indian men compared to US Caucasians had significantly lower trabecular vBMD [− 1.3 to − 1.5 standard deviation (SD)], cortical thickness [− 0.8 to − 1.2 SD]; significantly higher endosteal circumference [0.5 to 0.8 SD]; but similar cortical vBMD. Afro-Caribbean men compared to US Caucasians had similar trabecular vBMD but significantly higher cortical vBMD [0.9 to 1.2 SD], SSIp [0.2 to 1.4 SD], and tibial endosteal circumference [1 SD],ConclusionsIn comparison to US Caucasians, rural South Indian men have reduced bone strength (lower trabecular vBMD) and Afro-Caribbean men have greater bone strength (higher cortical vBMD). These results suggest an underlying higher risk of osteoporotic fractures and greater future fracture burden among rural South Indian men.

Ethnic Differences in Bone Microarchitecture

“…In a cross-cohort comparison between rural South Indian, the US Caucasian (MrOS) and Afro Caribbean (Tobago Cohort) men aged 60 and above, similar patterns were observed. Compared to the US-Caucasians, rural Indian men had lower bone strength, trabecular vBMD and cortical thickness, whereas Afro-Caribbeans’ had similar trabecular vBMD, higher cortical vBMD and greater strength [ 25 •], similar to the reported UK differences [ 24 ]. More studies are required to understand how bone geometry translates to fracture risk in men.…”

“…number* White American < Chinese-American and White American < Hong Kong Chinese (post-menopausal) Tb. separation* Chinese > Caucasian (pre-menopausal) Ct./total cross-sectional area, matrix mineral density* Matrix mineral density* [ 23 ] Caucasian > Chinese (pre-menopausal) Total cross-sectional area, Ct. area, medullary cross-sectional area, Ct. porosity (total*, compact-appearing*, outer transitional zone) Total cross-sectional area, Ct. area*, Medullary cross-sectional area*, Ct. porosity (total*, compact-appearing*, outer transitional zone*) Chinese > Caucasian (post-menopausal) Ct. porosity (inner transitional zone*) Ct. porosity (inner transitional zone*) Caucasian > Chinese (post-menopausal) Total cross-sectional area, Ct. area*, medullary cross-sectional area*, Ct. thickness*, Whole bone stiffness*, Failure load* Total cross-sectional area, Whole bone stiffness, Failure load pQCT in men Black Afro-Caribbean > White European and South Asian, White European > South Asian Ct. thickness*, Ct. area* (diaphysis) Ct. area*, Ct. thickness, Cross-sectional area, CSMI (diaphysis) [ 24 ] Rural South Indian < US Caucasian and Afro-Caribbean > US Caucasian Ct. thickness (diaphysis)** SSI (metaphysis)** [ 25 •] Rural South Indian<US Caucasian and Afro-Caribbean < US Caucasian Ct. thickness (diaphysis)** Rural South Indian>US Caucasian and Afro-Caribbean > US Caucasian Endosteal circumference (diaphysis)** HR-pQCT in young adults Caucasian > Asian men Total bone area*, Tb. area*, Tb.…”

Failure rates and factors associated with infrazygomatic crestal orthodontic implants - A prospective study

“…The reason for the lower success rate in our study may be attributed to lower cortical bone mineral density in Indians. 16 …”