Artifact in bone mineral measurements during a very low calorie diet - Short-term effects of growth hormone

Short-term effects of growth hormone on bone metabolism and soft tissue col lagen metabolism during weight loss in obese subjects on a very low calorie diet were investigated in a double-blind, placebo-controlled design. Twent y healthy, obese women (body mass index between 33 and 45 kg/m(2)) aged 21- 48 yr were followed for 8 wk: half received growth hormone. A 740-kcal diet was administered the first 4 wk, followed by a 1200-kcal diet. Lumbar spin e body mineral context (BMC), total-body fat mass, total-body lean body mas s, total-body BMC, and total-body bone area were measured by dual-energy X- ray absorptiometry along with biochemical markers of bone turnover. The body weight decreased by 5.5% and fat mass by 11.4%. There were no chan ges in biochemical bone markers in the placebo group despite a marked decre ase in BMC (3.1%). Projected total bone area decreased proportional to BMC (r(2) = 0.89) during the weight loss. Growth hormone treatment did not modu late the decrease in lean body mass, body weight, fat mass, or BMC, but inc reased bone turnover markers. Growth hormone did not change the results con cerning BMC, projected bone area, BMD, lean body mass, or fat mass. Because 89% of the observed change in BMC could be explained by alterations in projected bone area without changes in biochemical bone markers, it is concluded that a large part of the observed decrease in BMC during weight l oss may be caused by scanner artifact.