Male BMD varies by race
MedWire News: Bone mineral density (BMD) in older men varies substantially across race/ethnic groups and countries, study findings indicate.
Jane Cauly (University of Pittsburgh, Pennsylvania, USA) and colleagues found that among 7803 men from seven different races/ethnicities in four countries, total hip BMD was distributed across five strata: Afro-Caribbean men had the highest BMD, followed by African-American men, US Caucasian and US Hispanic men, US Asian and Hong Kong Chinese men, and South Korean men in lowest stratum.
The researchers explain that they carried out the study because epidemiologic information about men's BMD across race/ethnic groups and geographic locations is lacking.
They report that the age-adjusted mean BMD at the femoral neck, total hip, and lumbar spine was a significant 8-20% higher in Afro-Caribbean men and 6-11% higher in African-American men, compared with US Caucasian men.
US Caucasian and Hispanic men had similar hip BMD, but spine BMD was 3% lower in Hispanic men.
Asian men had significantly lower BMD than US Caucasians at all bone sites. Specifically, it was 3-5% lower in US Asian, 7-10% lower in Hong Kong Chinese, and 8-12% lower in South Korean men.
Cauly and co-authors note that Afro-Caribbean and US Asian men weighed less and were shorter than US Caucasian men, while Hong Kong Chinese and Korean men weighed less and were shorter than all the other race/ethnic groups.
When weight and height were taken into account, the differences in mean BMD at each site between Caucasian men and African-American men or Afro-Caribbean men persisted.
However, the adjustment for weight and height greatly attenuated differences in BMD between US Caucasian men and US Asian, Hong Kong Chinese, and Korean men.
This finding "illustrates the role of body size on the difference [in BMD] between these groups," the researchers remark.
Additional adjustment for lifestyle factors such as smoking, alcohol intake, and dietary calcium intake, resulted in only minor changes (-0.1%-0.9%) in the percentage differences between US Caucasian men and each of the other groups.
Writing in the journal Osteoporosis International, Cauly et al comment: "The differences in BMD depend both on genetic and environmental factors across countries and race/ethnic groups."
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By Laura Dean