OBJECTIVESTo clarify the relationship between bone mineral density (BMD) and body composition in Japanese women aged 18-40 years with low forearm BMD.

METHODSThe subjects were Japanese 199 women who had been selected for inclusion in the study based on a low forearm BMD determined at the Annual Women's Health Examination. The subjects' mean (+/- standard deviation) age, body height, body weight, and body mass index (BMI) were 33.5 (+/-4.3) years, 158.1 (+/-5.1) cm, 49.6 (+/-5.7) kg, and 19.8 (+/-2.1), respectively. The BMD of the lumbar spine, total body, and left arm were measured using dual-energy X-ray absorptiometry (DXA). Fat mass (FM), bone-free lean tissue mass (LTM), and body fat percentage (BF%) were measured simultaneously with DXA.

RESULTSIn the structural equation model, the standardized regression weights for the path from BMI to BMD of all sites were 0.273-0.434. Conversely, the BF% to BMD of the total body and left arm were -0.192 and -0.296, respectively. In multiple regression analysis, the FM index (FMI) was significantly associated with the BMD of the lumbar spine as a weight-bearing site. The LTM index (LTMI) was significantly associated with the BMD of the total body and left arm as a non-weight-bearing site.

CONCLUSIONSYoung females with low forearm BMD had low body weight and BMI. Thinness was shown to be a risk factor for low BMD, in accordance with results reported elsewhere. A gain in body weight may have the effect of increasing BMD, but our results suggest that to increase BMD, the gain in body weight must include increases in LTM, and not FM alone.

OBJECTIVEThe purpose of this study was to clarify the relationship between forearm bone mineral density (BMD), body mass index (BMI), and body composition focusing on body fat percentage (BF%) in Japanese females 18 to 40 years old.

METHODSSubjects were 2,280 females 18-40 years old. Anthropometric measurements were taken, and a medical history was obtained by questionnaire, including age at the time of the study and age at menarche. BF% was measured by bioelectrical impedance analysis. Forearm BMD was measured using dual-energy X-ray absorptiometry (DXA). The correlations of BMD with BMI and BF% were analyzed using a structural equation model.

RESULTSThe standardized regression coefficients for the path from BMI to BMD and the path from BF% to BMD were 0.538 and -0.184 respectively. The squared multiple correlation of BMD was 0.146. In addition, the standardized regression coefficient for the path from BMI to BF% was 0.896.

CONCLUSIONThe results showed a positive correlation between BMD and BMI and an inverse correlation between BMD and BF%. At the same time, it was noted that BF% increased with BMI. This indicated that BMD is dependant on BF% in subjects who have a similar BMI. Therefore, this study concluded that it is necessary to take body composition measurements into account when examining the relationship between BMI and BMD, especially in young females.

The objective of this study was to examine the association between body mass index (BMI) and blood pressure. Two sets of cross-sectional data were obtained from annual health examinations for adults aged 40 years and over (n=1,327 in 1993; n=1,302 in 2000) in Tsunagi area of Kumamoto Prefecture, Japan. BMI was associated with mean blood pressure and with prevalence of hypertension both in 1993 and 2000. The association was independent of age, smoking status and alcohol consumption. A significant increase in risk of hypertension was found in most categories of BMI 25.0 and above, and a greater than three fold increase in those with BMI of 27 and above compared with those with BMI of 18.5-22.9. Although mean blood pressure and prevalence of hypertension sharply decreased in 2000 compared with that in 1993, BMI was positively and independently associated with increased blood pressure.

OBJECTIVEClarify the relation between the complaints of wheelchair users and the vibration characteristics of the wheelchair, to improve wheelchair comfort and design.

METHODSThe question naires were distributed to 33 wheelchair users directly by the experimenter in order to identify the causes of complaints from wheelchair vibrations that they experienced. The vibration transmissibility of wheelchairs of ten subjects was measured to clarify the causes of complaints of wheelchair vibration according to the ISO 10326-1 standard in the laboratory using a broadband random vibration spectrum with a frequency-weighted vibration magnitude of 0.1 ms(-2) r.m.s. over the frequency range from 0.2 to 100 Hz. Each vibration exposure lasted 60 seconds.

RESULTSThe following findings were clear from the questionnaire results; (i) the vibration rom the wheelchair affected psychological comfort; (ii) the effects of different riding surfaces were important engineering issues affecting wheelchair ride comfort; (iii) the wheelchair users felt the vibration during wheelchair usage at locations on the neck, lower back and buttocks; (iv) vertical vibration was the most noticeable vibration from the wheelchair to each participant's body. The following findings were clear from the results of the transmissibility measurement of the wheelchair; (i) the resonance frequency-ranges of the transmissibility of the wheelchair showed significant differences between the subjects; (ii) intra-subject variability from three repeated transmissibility measurements was small; (iii) the first resonant frequency occurred approximately 5 to 7 Hz and the second resonant frequency occurred at around 8 Hz and the third resonant frequency occurred approximately 13 to 15 Hz; (iv) the magnitude of the peak transmissibility varied from 1.3 to 2.6.

CONCLUSIONFrom the comparison of the results of questionnaires and the transmissibility measurement of the wheelchair, the resonance frequency-ranges of the maximum vibration transmissibility of the manual wheelchairs were consistent with the frequency-ranges of the body parts of the causes of the complaints of wheelchair users. In addition, from these experimental results, it was suggested that the main point for improving a wheelchair user's comfort was to reduce the wheelchair seat vibration transmissibility at around 8 Hz and also to design wheelchair stiffness and damping characteristics to minimize vibration transmission at specific frequencies at body locations that caused the discomfort reported by wheelchair users.

OBJECTIVESThe goal of the present study was to describe the changes in activities of daily living (ADL) of community-dwelling Beijing elderly people (n=3,257), observed for 8 years, and to identify the demographic characteristic that predict the functional change.

METHODSTwo sets of interview data (1992 and 2000) were used to evaluate changes among the elderly in reports of limitation in ADL management.

RESULTSThe prevalence of disability increased over 8 years both in IADL and BADL disability. The patterns of ADLs change were bi-directional. A large proportion (74.7%) of the elderly were found to remain active in their functional states, 20.4% of the elderly declined, 3.4% of the elderly remained disabled, and 1.5% showed improvement in functional states. The transition rates from non-disability and disability states to various functional states showed different characteristic, a high disability rate accompanied a high mortality rate. The demographic factors that affected the level of disability among different kinds of population manifested similar trends.

CONCLUSIONAge was the most significant predictor for functional limitations. In addition, demographic variables played an important role in estimating functional outcomes. It is recommended that the demarcation factor for the evaluation of ADLs should be 75 years of age.

OBJECTIVEThe purpose of this study was to test the hypothesis that ADL disability affects the risk of onset of depressive symptoms and the role of possible confounding variables in this relation.

METHODSThe data was obtained from the Beijing Longitudinal Study of Aging, a community-based cohort study of 3,257 elderly, aged 55 through 99 years, who were assessed four time at an 8-year interval. ADL disability and depressive symptoms were assessed by self-reported measures.

RESULTSCompared with non-disabled persons, the disabled persons were associated with an increased risk of onset depression (RR=7.28 for urban, R=2.22 for non-urban). Although an adjustment for possible confounders reduced the risk for depression association with the disability, the detrimental effect of disability remained significantly present. This excess risk is partly explained by the lower satisfation with economy and poor perceived health status of the disabled elderly.

CONCLUSIONSDisability among elderly may significantly increase the risk for depressive symptoms.

To examine the work load of recent mechanized forestry work, energy expenditure, serum sarcoplasmic enzyme and urinary catecholamine were measured during engagement in the production of trees among twelve lumberjacks. Energy expenditure was relatively high in the works of debranching by a hatchet and hanging trees on carring wire cables. At least, the debranching work by a hatchet must be changed to more safety and lighter works. It was suggested that much more attention must be paid to the physiologic character of forestry work still now on the results of the changing pattern in serum sarcoplasmic enzyme and urinary catecholamine during these working process.

In order to observe the actual work types and the work load of female farmers in various kinds of agriculture that have gradually become a large part of agriculture in Japan as a result of changes in the structure of agricultural production, the authors performed a questionnaire and interview with a large number of female farmers (2, 113) and women in non-agricultural households.
Greenhouse farming was the most common work type for female farmers, followed by tobacco cultivation. The jobs conventionally undertaken by men, that have required a large dynamic work load, have been progressively mechanized, while auxiliary work before and after machinary work remain as manual labor by women. Some clear differences in the work type between full-time farming and part-time farming of female farmers were observed. On the other hand, it does not seem to be easy to estimate the work strain due to the work loads as mentioned above.

In the farm household of “vegetable planting by plastic green house”, “mandarin orange”, “rush (igusa)”, “dairy-farming” and “silk worm”, measurement of energy expenditure in agricultural work and analysis of daily working hours were conducted at the busy season of each crops. The results are as follows:
The energy consumption per day are estimated respectively to be 3300 Cal for male and 2900 Cal for female in the household of the “plastic green house”; 3500 and 2500 Cal in the “mandarin orange”, 3800 and 3600 Cal in the “rush”, 3300 and 2700 Cal in the “dairy-farming”, 3400 and 2700 Cal in the “silk worm”.
The agricultural machines and tools are mainly operated by male and so attached muscular works not yet machanized are carried by female. And management of animals or crops specially required prudent care have a tendency to be also carried by female. Then the average relative metabolic rate (RMR) a working day is relatively higher in female than male, except “mandarin orange”.
In the “rush harvesting” and “dairy-farming”, having the most development of the agricultural mechanization it seems obviousely to be rising the labor efficiency, but because of expansion of management scale and decreasing number of employee the reduction of work load for a worker is not necessory obvious.

A field study on the hourly working pattern, energy expenditure, air conditions and the testing for fatigue of the process of the raising silk worms for 4 days in August, the period of early autumn raising. Three couples of the typical raising silk worms households in Kikuchi district in Kumamoto Pref. were selected for the study. The results were as follows.
1. In Kikuchi district, there were 5-10 raising periods in a year from april to november for each households and the yearly working days for the process were to be 160-260 days.
In the period of early autumn raising, the average working times and energy expenditure a day were calculated to be 374±136 min. and 2891±277 kcal for males and 383±119 min. and 2494±91 kcal for females in the third state of period (after 5 days of accepting the larva); and in the fifth state of the process (after 10 days of the former state) 644±112 min. and 3087±136 kcal for males, 618±65 min. 2851±48 kcal for females; in the state of the spinning cocoons, 944±238 min. and 3735±459 kcal for males, 846±271 min. and 3209±754 kcal for females; in the state of the controlling cocoons, 560±115 min. and 2944±233 kcal for males, 478±68 min. and 2537±101 kcal for females. In the spinning state it was the highest work loads to be taken for both males and females through one raising period.
2. The RMR (relative metabolic rates) values of each elemental work were measured to be 0.6-3.7 (0.0322-0.0995 kcal/kg/min). The average RMR in a working time was 2.2±0.3 (1.7-2.9) for males and 2.1±0.3 (1.4-2.5) for females, and in the spinning state higher average value was observed for females than for males.
3. There was some difference between males and females in the distribution of working posture. For males 30.8%(9.5-46.2%) of all working times was the standing position, but in the contrally, for females, 66.0%(64.0-69.8%) was the half sitting position and only 11.0% was the standing position.
4. The considerable reduction of flicker frequency was observed at the end of working a day in each state of the period especially in the spinning state, and the increasing of complaints of fatigue symptoms was also observed.