Seiji Morioka

Determinants of bone loss in a rural Japanese community : the Taiji Study

Abstract: The objective of this study was to assess the rate of bone loss and characterize its determinants, among the inhabitants of Taiji, a rural Japanese community. A cohort of 2261 inhabitants aged 40–79 years was established using resident registration in 1992. Fifty men and 50 women in each of four age strata between 40 and 79 years were randomly selected and completed a self-administered risk factor questionnaire. Baseline bone density of lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry in 1993. BMD was measured again on the same participants in 1996. The rates of change of lumbar spine BMD in men in their 40s, 50s, 60s and 70s were 0.20%, 0.34%, 0.43% and 0.28% respectively. Rates in women were –0.35%, –1.02%, –0.10% and –0.20% respectively. At the femoral neck, rates of change in BMD among men in their 40s, 50s, 60s and 70s were 0.09%, –0.07%, 0.34% and 0.31% respectively. Femoral neck rates of change among women were –0.55%, 0.02%, 0.49% and –0.25% respectively. The rate of change of lumbar spine BMD was –0.24% in premenopausal women with regular periods, –1.99% in premenopausal women with irregular periods and –0.33% in postmenopausal women. Anthropometric measurements at baseline were also related significantly to change in bone density. Baseline weight and height were statistically significant predictors of bone loss rate.These data provide estimates of the rate of bone loss among Japanese men and women aged 40– 79 years. They suggest that body build and menstrual function in women are important determinants of bone loss.

Biochemical Markers of Bone Turnover and Bone Loss at the Lumbar Spine and Femoral Neck: The Taiji Study

Abstract. The purpose of this study was to ascertain whether biochemical markers of bone turnover predict bone loss. The survey was carried out in Taiji, Wakayama Prefecture, Japan. From a list of inhabitants aged 40–79 years, 400 participants (50 men and 50 women in each of four age groups) were selected randomly. Bone mineral density (BMD) was measured, and blood and urine samples of all participants were examined to obtain values for eight biochemical markers: alkaline phosphatase (ALP), bone Gla protein (BGP), type I procollagen (carboxyterminal peptide of type I procollagen; PICP), cross-linked carboxyterminal telopeptide region of type I collagen (ICTP), and urinary excretion of calcium (Ca), phosphate (P), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr). Each marker was evaluated as a predictor of the rate of bone change in lumbar spine and femoral neck BMD over a 3-year period. The value of Pyr was significantly related to the change of lumbar spine BMD in men (P= 0.009), and that of BGP was found to be significant in women (P= 0.045). By contrast, none of the bone markers significantly correlated with bone loss at the femoral neck. The coefficient of determination at the lumbar spine was 5% and 7% at the femoral neck only. We conclude that biochemical markers of bone turnover cannot predict bone loss rates in middle-aged or elderly Japanese men and women over a 3-year period with sufficient accuracy for use in clinical decision making.

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 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.

Joint Effects of Smoking and Alcohol Drinking on Esophageal Cancer Mortality in Japanese Men: Findings from the Japan Collaborative Cohort Study

BACKGROUND The purpose of our study was to elucidate the joint effects of combined smoking and alcohol intake on esophageal cancer mortality in Japanese men through a large cohort study with a 20-year follow-up period. MATERIALS AND METHODS The Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study) was established in the late 1980s, including 46,395 men and 64,190 women aged 40 years and older and younger than 80. Follow-up of these participants was conducted until 2009. We used the Cox proportional hazards model to analyze data for 42,408 people excluding female participants, 411 people with histories of malignant neoplasms, and 3,576 with unclear smoking and drinking data. RESULTS The joint effects of age at start of smoking and amount of alcohol consumed per day were compared with non-smokers and non-drinkers or those consuming less than one unit of alcohol per day. The mortality risk was 9.33 (95% confidence interval, 2.55-34.2) for those who started smoking between ages 10 and 19 years and drinking at least three units of alcohol per day. Regarding the joint effects of cumulative amount of smoking and alcohol intake, the risk was high when both smoking and alcohol intake were above a certain level. CONCLUSIONS In this Japanese cohort study, increased cancer mortality risks were observed, especially for people who both started smoking early and drank alcohol. Quitting smoking or not starting to smoke at any age and reducing alcohol consumption are important for preventing esophageal cancer in Japan.

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.

Bone metabolic marker levels in residents of a rural community in Japan

The sex and age distributions of values of bone metabolic markers were investigated among the inhabitants of a mountain village in Wakayama Prefecture, Japan. The survey was carried out in Miyama village, which has a population of 2372 (1129 men and 1243 women) based on the resident registration of 1990. In this village, all residents aged 40 years or over are eligible for general mass health examinations once a year. In the present study, bone metabolic markers were measured in recruited participants in the health examinations conducted in 1992 in each of four age strata: 40–49, 50–59, 60–69, and 70–79 years. The bone metabolic markers measured were osteocalcin (BGP), carboxyterminal peptide of type I procollagen (PICP), alkaline phosphatase (ALP), crosslinked carboxyterminal telopeptide region of type I collagen (ICTP), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr). In men in their 40s, 50s, 60s, and 70s, the mean serum BGP level was 6.15, 7.04, 7.65, and 7.69 ng/ml, respectively; the level in men in their 40s was significantly lower than that in those in their 60s. The serum PICP level in the 40- to 49-year age group was significantly higher than those in the other age groups, while that of serum ICTP tended to increase with age. The mean values of urinary Pyr and D-Pyr were higher in the older groups. In women, the mean values of all bone metabolic markers were all higher among those in the 50–59, 60–69, and 70–79 age groups compared to those in the 40–49 age group. These findings suggest that active bone metabolic turnover occurs even in the older age groups in both men and women.

Incidence of fast bone loss in residents of a rural community in Japan

A COMPARISON OF MXAANDRADIOGRAPHIC MORPHOMETRY ~N THE ASSESSMENT OF VERTEBRAL FRACTURES. K.Kushida, H.Hoshino, K.Yamazaki, A.Kitazawa, K. Atsumi, M.Ishikawa, T.Inoue, Department of Orthopaedic Surgery, Hamamatsu University School of Medicine. Morphometric x-ray absorptiometry (MXA) has be4n proposed as means of removing the obliquities and reducing the scatter which affect conventional lateral radiographs of the spine. We have compared morphometric X-ray absorptiometry (MXA) with radiographic assessment in osteoporotic patients. 66 osteoporotic subjects (mean age 69 years) were measured on morphometric X-ray absorptiometry using Lunar EXP-5000 device. All subject had dorsal and lumber lateral X-ray to measure the height of the vertebrae using fracture analysis system (FA) and to assess vertebral fractures non-quantitatively by an orthopedist (NQ). Analyses were performed from Thl0 toLl. The fracture criteria was less than 0.75 for A/P or less than 0.8 for C/P. The percentage of agreement whether the fracture has been occurred or not between MXA and NQ, FA and NQ, and MXAand FA were 98.9%, 97.7%, and 97.7%, respectively. T~e correlations between MXA and FA in each vertebrae were more than 0.6 for A/P and were slightly worse for C/P than those for A/P because the centr41 height was more affected by the obliquities in radiographic assessment. In conclusion, MXA using EXP-5000 appears a valuable method to evaluate vertebral fractures from the viewpoint of the agreement with radiographic assessment.

Distribution of bone mineral density of inhabitants in two areas in Wakayama Prefecture in Japan Comparison between mountain and seaside community

A COMPARISON OF MXAANDRADIOGRAPHIC MORPHOMETRY ~N THE ASSESSMENT OF VERTEBRAL FRACTURES. K.Kushida, H.Hoshino, K.Yamazaki, A.Kitazawa, K. Atsumi, M.Ishikawa, T.Inoue, Department of Orthopaedic Surgery, Hamamatsu University School of Medicine. Morphometric x-ray absorptiometry (MXA) has be4n proposed as means of removing the obliquities and reducing the scatter which affect conventional lateral radiographs of the spine. We have compared morphometric X-ray absorptiometry (MXA) with radiographic assessment in osteoporotic patients. 66 osteoporotic subjects (mean age 69 years) were measured on morphometric X-ray absorptiometry using Lunar EXP-5000 device. All subject had dorsal and lumber lateral X-ray to measure the height of the vertebrae using fracture analysis system (FA) and to assess vertebral fractures non-quantitatively by an orthopedist (NQ). Analyses were performed from Thl0 toLl. The fracture criteria was less than 0.75 for A/P or less than 0.8 for C/P. The percentage of agreement whether the fracture has been occurred or not between MXA and NQ, FA and NQ, and MXAand FA were 98.9%, 97.7%, and 97.7%, respectively. T~e correlations between MXA and FA in each vertebrae were more than 0.6 for A/P and were slightly worse for C/P than those for A/P because the centr41 height was more affected by the obliquities in radiographic assessment. In conclusion, MXA using EXP-5000 appears a valuable method to evaluate vertebral fractures from the viewpoint of the agreement with radiographic assessment.