BMD and fracture risk by age

(A) Bone loss begins in the third decade of life in both sexes. The data are from the Epidemiological Follow-up Study cohort of the NHANES I, a nationally representative sample of noninstitutionalized civilians who were followed for a maximum of 22 years. A cohort of 2879 White males (1437 in the bone density subsample) aged 45 to 74 years at baseline (1971 to 1975) were observed through 1992^[1].
(B) Age is a more critical determinant of fracture risk than bone mass in humans. Data are from a follow-up of 521 White females over an average of 6.5 years with repeated bone mass measurements at the radius. A total of 138 nonspinal fractures in 3388 person-years were detected, and the incident fractures were cross-classified by age and bone mass. The incidence of fracture was then fitted to a log-linear model in age and bone mass^[2].