Bone Mineral Changes in Obese Women During a Moderate Weight Loss With and Without Calcium Supplementation
作者:Lars Bjørn Jensen、Gina Kollerup、Flemming Quaade、Ole Helmer SØRensen
DOI:10.1359/jbmr.2001.16.1.141
日期:——
A significant relationship between body weight (BW) and bone mass (BM) has been established previously. A diet‐induced weight loss is accompanied by a significant decrease in bone mineral density (BMD) and total body bone mineral (TBBM), but the underlying mechanisms are not clarified. Sixty‐two obese women were included in the study. Dual‐energy X‐ray absorptiometry (DXA) and measurements of a series of calcium‐regulating hormones and biochemical markers of bone turnover were performed at baseline and after 1 month and 3 months on a low calorie diet. Thirty of the women were randomized to a daily supplement of 1 g of calcium. After an additional 3 months without dietary prescriptions or calcium supplements, a subgroup of 48 subjects (24 from each group) were scanned again using DXA. There was a significant decrease in TBBM after 1 month and 3 months. A similar pattern was observed in the bone mineral content (BMC) of the lumbar spine in the patients who did not receive a calcium supplement, whereas no changes occurred in the supplemented group. The initial calcium supplementation seemed to protect against bone loss in the lumbar spine but not in the TBBM. In the nonsupplemented group, a statistically significant inverse correlation was found between the calcium/creatinine ratio in the morning urine and the changes in BMC of the lumbar spine. Such a relationship was not seen in the calcium‐supplemented group. In the nonsupplemented group, no significant biochemical changes were observed, whereas a significant decrease in serum parathyroid hormone (PTH) was seen in the calcium‐supplemented group. This might explain some of the protective effects of calcium supplementation on trabecular bone mass. We conclude that a diet‐induced weight loss is accompanied by a generalized bone loss, which probably is explained mainly by a reduced mechanical strain on the skeleton. This loss can be partly inhibited by a high calcium intake. Therefore, a calcium supplementation should be recommended during weight loss, even if the diet contains the officially recommended amounts of calcium.
体重(BW)与骨量(BM)之间的重要关系已被证实。节食引起的体重减轻伴随着骨矿物质密度(BMD)和全身骨矿物质(TBBM)的显著下降,但其潜在机制尚未明确。研究共纳入了 62 名肥胖女性。在低热量饮食的基线期和 1 个月后及 3 个月后进行了双能 X 射线吸收测量(DXA)和一系列钙调节激素和骨转换生化指标的测量。其中 30 名妇女被随机安排每天补充 1 克钙。在不服用饮食处方或钙补充剂的情况下再过 3 个月后,再次使用 DXA 对 48 名受试者(每组 24 人)进行扫描。1 个月和 3 个月后,TBBM 明显下降。未接受钙补充剂治疗的患者腰椎骨矿物质含量(BMC)也出现了类似的情况,而接受钙补充剂治疗的患者腰椎骨矿物质含量则没有变化。最初的钙补充似乎能防止腰椎的骨质流失,但不能防止 TBBM 的骨质流失。在未补钙组中,晨尿中的钙/肌酐比值与腰椎的 BMC 变化之间存在统计学意义上的显著负相关。而补钙组则没有发现这种关系。未补钙组未观察到明显的生化变化,而补钙组血清甲状旁腺激素(PTH)明显下降。这可能解释了补钙对骨小梁质量的一些保护作用。我们的结论是,节食引起的体重减轻伴随着普遍的骨质流失,这可能主要是由于骨骼的机械应变减少所致。高钙摄入可以部分抑制骨质流失。因此,在减肥期间,即使饮食中含有官方推荐的钙量,也应建议补充钙剂。