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一项为期十年的队列研究，测量了骨密度（BMD），以提供有关成熟和老年人口骨质流失率的信息，并比较了快速骨质流失和正常居民骨密度的时间过程。根据性别和年龄从1910-1949年出生的全部居民名单中选择400名受试者，使用双能x线骨密度仪（DXA）在基线、第3年、第7年和第10年测量腰椎和股骨近端骨密度。40岁、50岁、60岁和70岁男性腰椎骨密度年变化率（% /年）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，但年龄最大的人则有所下降，而在女性中，所有年龄段的骨密度都有所下降。股骨近端MD在所有年龄层中男女均有所下降。我们的研究结果表明，骨质流失率取决于所涉及的死亡部位，这表明需要不同的策略来预防脊柱和髋关节的骨质流失。快速骨质流失被定义为那些在最初三年内骨质流失分布中表现出超额骨质流失的受试者，其余的被归类为正常受试者。快速失骨组和正常组的腰椎骨密度平均值在10年期间均有明显下降，但快速失骨组明显低于正常组（P<0.01）。然而，在快速骨质流失和正常受试者之间，十年来骨密度的平均变化率没有差异。

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.