The effect of advancing age on bone mineral content of female rhesus monkeys

Abstract

Dual-energy X-ray absorptiometry (DXA) can be used to assess bone mass in nonhuman primates; however, the changes in bone mineral across the lifespan have not been well described. The purpose of this cross-sectional study was to evaluate the effect of maturation and subsequent aging on bone mineral content (BMC) and bone size (two dimensional bone area) in female rhesus monkeys at sites analogous to those commonly evaluated in humans. Total body (n = 178) and lumbar spine (n = 167) DXA scans were performed on female rhesus monkeys aged 2.8 to 34.6 years. Radius scans (n = 86) were performed on monkeys aged 9.7 to 34.6 years. Measurement precision was comparable to that reported for humans. At all sites, BMC was highly correlated with bone area (p = 0.0001), which was positively correlated with both body weight (p < or = 0.002) and age (p < or = 0.08). Total body and lumbar spine BMC and bone area increased with maturation (p < 0.0001) until age 11 and then remained stable with further advancing age. There was little change in total body and lumbar spine area-adjusted BMC across the lifespan. At the radial sites, there were no significant changes in BMC or bone area with age, but the area-adjusted BMC and the weight- and area-adjusted BMC declined in older animals (p < 0.05). In conclusion, the female rhesus monkey does not attain peak bone mass until age 11. Significant bone loss at later ages was observed only at radial sites.