ASYNCHRONY BETWEEN THE RATES OF STANDING HEIGHT GAIN AND BONE MASS ACCUMULATION DURING PUBERTY

During puberty, the marked increases in both standing height and bone mass appear to be dissociated in time, the former occurring earlier th an the latter. However, the age or pubertal stage at which this dissoc iation is maximal in girls as opposed to boys, and whether this dissoc iation is similar at all parts of the skeleton, are not clearly establ ished. Standing height and bone mineral mass, as assessed by measuring areal bone mineral density (BMD), at the levels of the lumbar spine, femoral neck and midfemoral shaft, were measured in 98 females and 100 males between the ages of 9 and 19 years twice at a 1-year interval. In males, the greatest difference between height and BMD gains occurre d in the 13-14 year age group and was more pronounced for the lumbar s pine and femoral neck than for the midfemoral shaft. In females, the g reatest difference was detectable at a younger age (11-12 year age gro up) and appeared to be of a lower magnitude than in males. In both gen ders, the maximal difference occurred during the period of peak height velocity, which corresponded to the pubertal stages P2-P3. Such a dis sociation between the rates of statural growth and mineral mass accrua l could define a state of relatively low bone mass and contribute to t he higher incidence of fracture known to occur at the age and/or puber tal stage when this dissociation is maximal.