关键词: 老年人, 骨密度, 身体成分

Abstract: Objective　 To study the changes in bone density （BD） and body composition with aging among middle-aged and older urban-dwelling females，and to offer suggestions for scientific exercising.Methods　421 healthy middle-aged and older healthy females were enrolled from 10 urban communities of a city in Shandong Province and were stratified into age groups of 55-59，60-64，65-69，70-74.OsteoPro UBD2002A Ultrasonic Bone Densitometer was used to measure the BD.ZEUS 9.9 Body Composition Analyzer was adopted to examine the parameters associated with muscle，fat，water and so on.Comparisons of the above indicators were made between the 4 age groups.Results　Except the body fat parameters （P>0.05），the bone mineral content，osteoporosis index （OI），the T-score and Z-score of BD，total body skeletal muscle mass，total body protein mass，left upper extremity skeletal muscle mass，right upper extremity skeletal muscle mass，left lower extremity skeletal muscle mass，right lower extremity skeletal muscle mass，trunk muscle mass，total body water volume，total body water percentage，volumes of intracellular and extracellular fluid，and edema index differed significantly between the 4 age groups （P<0.05）.In more detail，70-74 age group showed lower bone mineral content compared with 60-64 age group and lower T-score of BD compared with age groups of 60-64 and 65-69 （P<0.05）； age groups of 60-64 and 70-74 presented lower Z-score of BD than 65-69 age group （P<0.05）； 70-74 age group demonstrated less total body skeletal muscle mass and total body protein mass compared with other age groups （P<0.05）； 70-74 age group showed less left upper extremity skeletal muscle mass compared with other three younger age groups （P<0.05），and 65-69 age group also showed less left upper extremity skeletal muscle mass than other two younger age groups （P<0.05）； age groups of 65-69 and 70-74 had less right upper extremity skeletal muscle mass compared with age groups of 55-59 and 60-64 （P<0.05）； 60-64 age group showed more right lower extremity skeletal muscle mass than 65-69 age group （P<0.05）； 70-74 age group showed less trunk muscle mass than age groups of 60-64 and 65-69 （P<0.05）； the total body water volume，volumes of intracellular and extracellular fluid were less in 70-74 age group compared with other age groups （P<0.05）； total body water percentage was lower in 70-74 age group than in 65-69 age group （P<0.05）； edema index was lower in age groups of 55-59 and 70-74 compared with age groups of 60-64 and 65-69 （P<0.05）.Conclusion The age of 70 is a critical period for the changes in bone density and body composition with aging for middle-aged and older urban-dwelling females.In age periods of 65-70 and 70-75，bone loss，and loss of skeletal muscle mass，and total body water accelerate implicitly and explicitly，respectively.In view of this，suggestions are put forward as follows： 1.Appropriate exercising intervention and water supply should be performed to prevent or delay the development of such changes.2.Priorities should be given to particular skeletal muscles during functional training exercises and the order of exercise should be arranged properly，if rapid atrophy of lower extremity skeletal muscles appears earlier than that of trunk muscles.3.Muscular training should be strengthened for muscle atrophy may greatly contribute to the osteoporosis and deficiency of body fluid.

Key words: Aged, Bone density, Body composition