Arm span, height and forearm bone mineral density in normal young and postmenopausal women.

The value of arm span and height measurements in the erect position were evaluated by (1) comparing them in individual young adults and postmenopausal women and (2) comparing them with forearm bone mineral density (BMD) using a Panasonic dual energy X-ray absorptiometry (DXA). The study group consisted of 301 healthy women composed of 165 young adults (20-40 years), 62 postmenopausal women and 74 women whose age was more than 40 and had regularity of menstruation. Arm span and height of the individual young adults and postmenopausal women were not significantly different (p>0.05). It indicated that arm span and height measurements were independent of normal aging. Height loss occurred in some elderly women who had some diseases or conditions which induced short stature. We suggested that arm span can be used to predict height during the younger adult life of elderly women and to predict the current height in patients who had a height loss problem. A simple linear regression equation of height and arm span has already been constructed. During the increase of years since menopause in postmenopausal women, height and arm span measurements were relatively constant, while BMD gradually declined. We also found that the greater the number of years since menopause, the higher the rate of BMD loss (%). Height and arm span had low correlation with BMD. Height or arm span alone can not be used to predict BMD, but may be combined with other risk factors of osteoporosis.

Prediction of bone mineral density of lumbar spine, hip, femoral neck and Ward's triangle by forearm bone mineral density.

Bone mineral density (BMD) of dual energy X-ray absorptiometry (DEXA) at both radius and ulna were measured to evaluate the correlation of those and BMD at lumbar (L) spine, hip, femoral neck and Ward's triangle. The 64 simple linear regression analysis was calculated to postulate the predicted equation by using the BMD at supradistal, distal 1/10, distal 1/6 and distal 1/3 of both forearms as independent variables, while the dependent variables were BMD at L1-L4 spine, total hip, femoral neck and Ward's triangle. 115 patients aged between 41-79 years (mean age 55.97+/-8.34 years) from the menopausal clinic, Pramongkutklao Hospital, were scanned at both forearms by Panasonic (DXA-70) DEXA and at non forearm regions by Hologic (QDR 4500) DEXA on the same day. The results showed that the BMD of each of the 4 parts of both radius and ulna had positive correlation to those of L-spine, total hip, femoral neck and Ward's triangle with r = 0.4012 to 0.7032 (P<0.001 for all). The greater distal of the forearm, the better correlation of BMD to the non forearm BMD. The 64 simple linear regression equations were constructed with regression coefficient ranging from 0.6048 to 1.9011 (P<0.001 for all). When considering the non forearm BMD, the mean BMD at Ward's triangle significantly declined more rapidly than that of L-spine, total hip and femoral neck (P<0.05 for all). It indicated that there was an early change of BMD at Ward's triangle. However, this change followed the forearm BMD. Distal forearm BMD was the earliest sign of bone loss. We can predict non forearm BMD by supradistal and distal 1/10 of forearm BMD.