Hirofumi Kinoshita

Bone loss at the lumbar spine and the proximal femur in a rural Japanese community, 1990-2000: the Miyama study.

Abstract: Bone mineral density (BMD) was measured over a ten year period in a cohort study in Miyama village, Wakayama Prefecture, Japan, to provide information on rate of bone loss in the mature and elderly population. Four hundred subjects were selected by sex and age decade from the full list of residents born in 1910–1949, and aged 40–79 years at the end of 1989, with 50 men and 50 women in each age decade. Baseline BMD of the lumbar spine and the proximal femur was measured using dual energy X-ray absorptiometry (DXA) in 1990 and again in 1993, 1997 and 2000. 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, whereas in women, it decreased in all age strata. On the other hand, BMD at the proximal femur decreased in both sexes in all age strata. Our results show that bone loss rates differ depending on the site involved, demonstrating that different strategies are needed for the prevention of bone loss in the spine and hip. Furthermore, we found evidence of differences in BMD for given age strata between birth cohorts. Data in 1990 and in 2000 showed significant improvements for men in their sixties and for women in their fifties, suggesting that future problems of osteoporosis might be less severe than has previously been predicted in Japan.

Epidemiological study on the bone mineral density of inhabitants in Miyama Village, Wakayama prefecture (Part II) bone mineral density of the spine and proximal femur

Reference values of bone mineral density (BMD) have mainly been based on hospital volunteers in Japan. Consequently, these values may be inappropriate for the use as a standard in the osteoporotic study. In order to establish reference values, BMD was measured of 400 age-stratified inhabitants of Miyama Village, utilizing dual energy x-ray absorptiometry (DEXA).The mean BMD of L2–L4 in males in each age group was 1.19±0.16 g/cm2 (mean±standard deviation) in 40s, 1.15±0.19 g/cm2 in 50s, 1.03±0.18 g/cm2 in 60s and 1.06±0.25 g/cm2 in 70s. The difference of BMD was statistically significant between the 50 and 60 age groups. On the other hand, in females the mean BMD of L2–L4 was 1.18±0.16 g/cm2 in 40s; 0.99±0.18 g/cm2 in 50s, 0.84±0.19 g/cm2 in 60s and 0.78±0.17 g/cm2 in 70s. The BMD was significantly lower in the 50 age group than in the 40 age group and was similarly lower in the 60 age group than in the 50 age group.The mean BMD of femoral neck in males was 0.98±0.14 g/cm2 in 40s, 0.91±0.12 g/cm2 in 50s, 0.83±0.11 g/cm2 in 60s and 0.78±0.11 g/cm2 in 70s. In females, the BMD of femoral neck was 0.88±0.11 g/cm2 in 40s, 0.75±0.11 g/cm2 in 50s, 0.68±0.11 g/cm2 in 60s and 0.63±0.10 g/cm2 in 70s. BMD of the femoral neck in an older age group was lower than that in a younger age group both in males and females.

Epidemiological study on the bone mineral density of inhabitants in Miyama Village, Wakayama prefecture (Part I) background of study population and sampling method

This report describes details of the sampling method and background of the population selected for bone density measurements.A list of inhabitants aged 40 to 79 years in Miyama Village, Wakayama Prefecture, was compiled based upon resident registration as of December, 1988. 1543 subjects consisting of 716 males and 827 females were identified. In order to measure bone density, a total of 400 subjects consisting of 200 males and 200 females were recruited from this list. Most were recruited from a centralized community and the remainder came from nearby areas, to give 50 people in each of eight age-sex groups. All of the selected people were contacted and agreed to participate. In Miyama Village, two large projects in relation to cancer and circulatory diseases are also being carried out as a part of national projects. As a consequence, Various information such as clinical history, personal history, blood analysis and so forth could be obtained for subjects who underwent bone density measurements. From these data, it was found that the percentages for smokers, drinkers and hypertensive subjects were similar to those of other communities and also to those in a nationwide survey. Moreover, we observed no abnormalities in serum calcium and phosphorus levels referable to bone turnover.These facts suggest that a representative sample population for measurements of bone density was drawn from the community.

Decreased activities of daily living and associations with bone loss among aged residents in a rural Japanese community: the Miyama Study

The present study aimed to clarify frequencies of decreased activities of daily living (ADL) and associations with rate of bone loss among inhabitants more than 60 years old in Miyama, a rural community in Japan. A cohort of 1543 inhabitants aged 40–79 years was established according to Miyama resident registrations in 1989. Men (n = 50) and women (n = 50) from each of two age strata between 60 and 79 years (N = 200) were selected from this cohort, and bone mineral density (BMD) of the lumbar spine and proximal femur was measured using dual-energy X-ray absorptiometry in 1990 (initial survey) and again in 1993, 1997, and 2000. Difficulties involving ADL were surveyed at every follow-up study. Of the 200 initial participants, 124 (57 men, 67 women; 62.0%) completed all BMD measurements and answered all items about ADL in the follow-up survey. The following items were investigated as a general indication of changes to ADL: reaching objects on a high shelf or cupboard (reaching); washing and drying the body (washing body); washing hair over a washbasin (washing hair); sitting for 1 h on a hard chair (sitting); raising the torso from a lying position in bed (raising); standing continuously for 30 min (standing); taking socks on and off the feet (taking socks); bending down from a seated position and picking up a small object at the side of the chair (bending); lifting heavy objects (lifting); and running 100 m without stopping (running). Among ADL items, the most frequent difficulties in men involved running (50.0%), followed by raising (30.6%), standing (27.1%), sitting (24.7%), and reaching (16.5%). In women, difficulties involved running (67.0%), followed by lifting (36.3%), standing (33.1%), reaching (30.8%), and sitting (23.6%). To evaluate relationships between decreased ADL and changes in BMD, annual rates of change for BMD at the lumbar spine and femoral neck were compared to changes for each ADL item (2 grade decrease; 1 grade decrease; or no change). Analysis of covariance (ANCOVA) was then performed on decreased ADL and annual bone changes after adjustment for age, concomitant disease (previous fractures, gastrectomy, diabetes mellitus, and renal dialysis at initial survey). In men, annual rates of change in BMD at the femoral neck over 10 years were significantly correlated with decreased abilities in bending (P = 0.046; R2 = 0.10). In women, annual rates of change in BMD at the lumbar spine over 10 years were significantly correlated with decreased abilities in reaching (P = 0.007; R2 = 0.25), and lifting (P = 0.014, R2 = 0.27), and those at the femoral neck were significantly correlated with decreased abilities in lifting (P = 0.001, R2 = 0.33).

Characteristics and course of bone mineral densities among fast bone losers in a rural Japanese community: the Miyama Study

The aim of this study was to clarify and compare the temporal course of bone mineral density (BMD) between fast bone losers and normal residents in Miyama Village, a rural Japanese community. BMD was measured over a 10-year period in a cohort study in Miyama Village, Wakayama Prefecture, Japan, to provide information on rate of bone loss in the mature and elderly population. Subjects (n=400) were selected by sex and age stratum from the full list of residents born in 1910–1949, with 50 men and 50 women in each age decade. Baseline BMD of the lumbar spine and proximal femur was measured using dual energy X-ray absorptiometry in 1990, 1993, 1997 and 2000. In the cohort, 171 men and 189 women completed the follow-up survey performed in 1993. After calculating the rate of bone loss between 1990 and 1993, the greatest tertile from the distribution of bone loss was categorized as fast bone losers, with the remainder considered as normal subjects. Changes in BMD were compared between normal subjects and fast bone losers over the 10-year period. Mean rate of change for BMD at both lumbar spine and femoral neck in fast bone losers recovered to levels similar to those in normal subjects over 7 years of observation. By contrast, BMD at the lumbar spine and femoral neck decreased steeply over the 10-year period in both groups, and mean BMD for fast bone losers was significantly lower than that of normal subjects (P<0.05). These differences were apparent only at the lumbar spine in both men and women, even after adjusting for age. These results indicate that fast bone loss is a transient phenomenon rather than a fixed status, although individuals who have been categorized as fast bone losers at some stage continue to display low BMD in the lumbar spine.