A PROSPECTIVE COHORT STUDY OF BONE LOSS AND OSTEOPOROTIC FRACTURES IN A RURAL JAPANESE COMMUNITY. THE EFFECT OF NUTRITION, PHYSICAL EXERCISE, ENVIRONMENTAL AND FAMILIAL FACTORS

在日本和歌山县的一个山村进行了为期10年的骨密度(BMD)测量，以提供有关成年和老年人群骨丢失速度的信息，并比较骨量快速减少者和正常居民之间的骨密度时间进程。从出生于1910-1949年的全部居民名单中按性别和年龄选择400名受试者，并使用双能X射线骨密度仪(DXA)在基线、第3年、第3年、第2年和第10年测量腰椎和股骨近端的BMD。男性40、50、60和70岁时腰椎骨密度年变化率分别为0.17、0.55、0.01和-0.16，女性分别为-0.87、-0.83、-0.48和-0.48。因此，在男性中，腰椎的骨密度在所有年龄段都有所增加，但年龄最大的腰椎的骨密度在下降时是增加的，而在女性中，腰椎的骨密度在所有年龄段都下降了。股骨近端的骨密度在所有年龄段中都下降了。我们的结果显示，不同部位的骨丢失率不同，这表明需要采取不同的策略来预防脊柱和髋部的骨丢失。快速骨量减少者被定义为那些在最初三年内表现出过多骨丢失的受试者，这是骨丢失分布的最大三分之一，其余的被归类为正常受试者。尽管腰椎骨密度在10年间在快速骨量减少组和正常组均急剧下降，但快速骨量减少组的腰椎骨密度值显著低于正常组(P&lt；0.01)。然而，在骨量快速下降的受试者和正常受试者之间，骨密度在十年内的平均变化率没有差别。

Bone mineral density (BMD) was measured over a ten year period in a cohort study in a mountain village, Wakayama Prefecture, Japan, to provide information on rate of bone loss in the mature and elderly population and to compare the temporal course of BMD between fast bone losers and normal residents.Four-hundred subjects were selected by sex and age from the full list of residents born, in 1910-1949, and BMD of the lumbar spine and proximal femur was measured using dual energy X-ray absorptiometry (DXA) at the baseline, third, severth, and 10th years. Annual rate of change in BMD (% per year) in the lumbar spine in men in their forties, fifties, sixties and seventies was 0.17, 0.55, 0.01 and -0.16, respectively, and in women, -0.87, -0.83, -0.48 and -0.48, respectively. Thus in men, BMD at the lumbar spine increased in all age strata but the oldest, when it decreased, while in women, it decreased in all age strata.MD at the proximal femur decreased in both sexes in all age strata. Our results show that bone loss rates differ depending on die site involved, demonstrating that different strategies are needed for the prevention of bone loss in the spine and hip. Fast bone losers were defined as those subjects demonstrating an excess bone loss that was the greatest tertile of the distribution of bone loss between initial three years, and the rest were classified as normal subjects. Although mean values of BMD at lumbar spine over a ten year period decreased steeply in both fast bone losers and normal subjects, those for fast bone losers was significantly lower than that of normal subjects (P<0.01). However, there was no difference of mean rate of change for BMD over ten years between fast bone losers and normal subjects.