Tetracycline double-labeling of iliac trabecular bone in 41 normal adults.

A histomorphometric evaluation of the iliac crest trabecular bone remodeling was performed after tetracycline double-labeling in 41 normal Danes (12 males and 29 females) aged 19 to 56 years. The fraction of formative (osteoid covered) and resorptive surfaces was unrelated to age but higher in males than in females (P less than 0.02 and P less than 0.05, respectively). The appositional rate (0.65 +/- 0.12 micrometer/day) was unrelated to age and sex, whereas the fractional labeled surfaces were higher (P less than 0.01) in the males (0.18 +/- 0.08 micrometer2/micrometer2) than in the females (0.12 +/- 0.05 micrometer2/micrometer2), and among the females inversely related to age (R = -0.38, P less than 0.05). The bone formation rate at BMU level (0.50 +/- 0.20 micrometer3/micrometer2/day) was unrelated to sex, but among the females inversely related to age R = -0.49, P less than 0.01). The bone formation rate at tissue level was higher (P less than 0.02) in the males (0.13 +/- 0.07 micrometer3/micrometer2/day) than in the females (0.07 +/- 0.03 micrometer3/micrometer2/day) and among the females inversely correlated to age (R = -0.43, P less than 0.05). the age- and sex-dependent variations in the dynamic parameters underline the importance of a more elaborated normal material.