本研究目的在比較正常骨質密度與骨質較低停經婦女，其身體活動量與骨質密度是否有差異。以雙能量X光吸收儀(dual energy X-ray absorptiometry, DEXA)，測量受試者腰椎L2-4及左股骨頸的骨質密度(bone mineral density, BMD)，均低於年輕女性1個標準差以上者，列爲骨質較低組有102人（平均年齡54.5±4.90歲），另以41人正常者爲骨質健康組（平均年齡53.7±4.47歲）。並以七日身體活動回憶問卷，調查受試者的身體活動量。但爲避免日常飲食鈣質影響骨質變化，及深入了解骨質之代謝情形，所以同時觀察受試者的鈣質攝取量與骨生化代謝指標氮末端胜肽(N-telopeptides, NTx)。所得結果以t檢定，來考驗兩組的同質性，另爲考量兩組間的的體重差異及荷爾蒙和鈣質的可能影響，乃以MANCOVA 來檢定身體活動量、BMD及NTx的差異情形，並將體重、停經年數及鈣質攝取量列爲共變項(covariate)，顯著水準定爲p<0.05。結果發現，骨質較低組的劇烈活動時間、能量消耗、L2-4及股骨頸骨質密度(BMD)，均明顯低於骨質健康組；但在NTx方面，則明顯高於骨質健康組。顯示骨質較低組較少從事劇烈活動，身體活動量偏低，並有較高的骨質分解代謝率。因此建議，婦女朋友們宜增加日常身體活動量，將有助於維持或增進骨質密度。

The purpose of this study was to determine the relationship of physical activities with bone mineral density (BMD) in postmenopausal women. Through dual energy X-ray absorptiometry (DEXA) measurements, 102 women with BMD more than one standard deviation below (T-score < -1.0 SD) were grouped as osteopenia group (average age 54.5 ± 4.90/yrs), 41 women with BMD less than one standard deviation below (T-score > -1.0 SD) grouped as healthy group (average age 53.7 ± 4.47/yrs) were included in this study. Age, height, body weigh, body mass index (BMI), duration of menopause and calcium intake were testified with t-test for both groups and showed only significantly difference in body weight. Considering hormone status and calcium intake were critical to BMD, together with body weight, we put them as covariance. Physical activities, BMD, and bone resorption marker (assessed by urinary N-telopoptides (NTx)) were analyzed with MANCOVA. The results showed physical activities was significantly lower and NTx significantly higher in osteopenia group (p<0.05). It is our recommendation that womankind should increase regular physical activities to benefit bone mineral density.