Taiki Komatsu

Effect of combined exercise training on bone, body balance, and gait ability: a randomized controlled study in community-dwelling elderly women

The purpose of this study was to investigate whether a 48-week multicomponent exercise program could improve the risk factors for fall and hip fracture. Fifty elderly women 65–70 years of age participated. These participants were divided into an exercise group (25 subjects) that attended an exercise program and a control group (25 subjects) that did not. The exercise program included stretching for 9 min, strength training for 10 min followed by 23 min of weight-bearing exercise at an intensity above 65%–75% of the maximal heart rate, and 18 min of balance and posture correction training. The program was conducted three times per week for 48 weeks. The 10-m maximal walk time, maximal step length, and eyes-open-one-legged-stand time in the exercise group improved significantly (P < 0.05). Concerning deoxypyridinoline, the exercise group achieved a significant improvement (P < 0.05) after the 48 weeks. Bone mineral density (BMD) of the femoral neck and trochanter in the exercise group was significantly increased after the exercise program; also body sway was significantly improved (P < 0.05). In conclusion, a multi-component exercise program with weight-bearing exercise at a moderate intensity and gait training may be effective in offsetting a decline in BMD and improving aggravation of bone resorption in this population. In addition, this program has a positive effect on postural stability and gait ability.

Clinical factors as predictors of the risk of falls and subsequent bone fractures due to osteoporosis in postmenopausal women

In Japan, the “bedridden state” is one of the most serious problems the aged face, and it is becoming a social problem. The main causes of the bedridden state are cerebrovascular disorders and bone fractures following falls. The purpose of this study was to predict risk factors for falls and resultant bone fracture due to osteoporosis. We explored mobility parameters for possible fall prevention. In order to examine the correlation between the risk of falling and resultant bone fracture due to osteoporosis, logistic regression analysis was performed between bone mass (independent variable) and various factors dependent variables: body mass index [BMI], body fat percentage, atherogenic index, presence of transformation-related osteoarthritis of knee, presence of transformation-related osteoarthritis of spine, maximum step length, single-leg stance with open eyes, and hip-joint flexion motion angle); predictive factors were then examined. Predictive factors were determined by the stepwise method. Subjects who could not perform the “single-leg stance with open eyes” test had a risk of falling and bone fracture 2.49 times as large as that of subjects who could. The “single-leg stance with open eyes” test may be considered a useful method for the early detection of the risk of falling and bone fracture associated with osteoporosis. As a first step to identify factors predicting the occurrence of falls and bone fractures due to osteoporosis, we intended to discover an indicator that would help to detect incipient osteoporosis.

Cortisol level measurements in fingernails as a retrospective index of hormone production

The cortisol level in fingernails may reflect the hormones cumulative production over a long period, but the notions have not been fully established. In this study, we investigated the association of cortisol in fingernails with cortisol accumulation over a long period (hair cortisol) and over a relatively short period (salivary cortisol). In study 1, hair and fingernail samples were collected from 58 middle-aged and elderly men. The cortisol level in hair samples was moderately associated with the level in fingernail samples (r = 0.29, p < 0.05 and rs = 0.36, p < 0.01). In study 2, 37 workers provided 4 saliva samples over the course of one day (at awakening, 30 min after awakening, before lunch, and after work) and another set a month later. Further, the workers were asked to provide fingernail samples during a six-month period. We found that the cortisol level in saliva over the whole day (area under the curve for cortisol) was moderately associated with the cortisol level measured in fingernail samples that were collected 4 months (r = 0.43, p < 0.05 and rs = 0.50, p < 0.01) and 5 months later (r = 0.45, p < 0.05 and rs = 0.53, p < 0.01). These results indicated that the cortisol level in fingernail samples might retrospectively represent hormone production during a given period. The cortisol level in fingernail samples may be useful in the investigation of the link between psychosocial stress and health.

Association of body mass index with lifestyle and rotating shift work in Japanese female nurses

Higher body mass index (BMI) values have been reported in rotating shift workers compared with regular daytime workers. This study examines the relationship between work schedule and BMI, and considers whether lifestyle habits could explain the relationship.

Diurnal 24-Hour Rhythm in Ambulatory Heart Rate Variability during the Day Shift in Rotating Shift Workers

Circadian variation in cardiac autonomic nervous system activity and behavior during the day shifts of shift workers has not hitherto been clarified. This study examined diurnal 24-h variation in heart rate variability (HRV), sleep-wake cycle, physical activity, and food intake during the day shift in rotating shift workers. The subjects were female nurses and caregivers working at a health care facility (14 day workers and 13 rotating shift workers). Each subject was asked to undergo 24-h electrocardiograph and step count recordings. Coarse graining spectral analysis was used for approximately 10-min segments of HRV (600 beats) to derive the total power (TOT: >0.04 Hz), integrated power in the low-frequency (LF: 0.04-0.15 Hz) and high-frequency (HF: >0.15 Hz) ranges, the ratio of HF power to TOT (HF nu), and the ratio of LF power to HF power (LF/HF). Double cosinor analysis was used to obtain 24-h and 12-h period variations in variables of HRV and physical activity. While no difference was found in the acrophases of either period for step counts or in the 12-h period of HRV variables between the groups, the acrophases of the 24-h period for HRV variables were delayed by 1.3 to 5.5 h in rotating shift workers, and their differences in HF power, HF nu, and LF/HF reached a significant level (p < 0.05). On the days of the experiment, retiring time, waking up time, total time in bed, sleep efficiency, and mealtimes and energy intake for each diet did not differ between the groups. These results suggest that there is a possibility of an abnormal phase angle between circadian variation in cardiac autonomic nervous system activity and the sleep-wake cycle during the day shift in shift workers.

Association between depressive symptoms and morningness-eveningness, sleep duration and rotating shift work in Japanese nurses

ABSTRACT Higher depressive symptoms have been reported in rotating shift workers compared with day workers. Depressive symptoms in adults who do not engage in night work have also been shown to be associated with chronotype and sleep duration. This study examines associations between depressive symptoms, morningness-eveningness (i.e. the degree to which people prefer to be active in the morning or the evening), sleep duration and rotating shift work. Japanese nurses (1252 day workers and 1780 rotating shift workers, aged 20–59) were studied using a self-administered questionnaire. The questionnaire covered depressive symptoms, morningness-eveningness, sleep habits and demographic characteristics of the participants. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to determine the levels of depressive symptoms. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure morningness-eveningness. The CES-D score of shift workers was significantly (p < 0.05) higher than that of day workers. The MEQ score was significantly (p < 0.05) lower (i.e. greater eveningness) in shift workers than in day workers. Sleep duration on the day shift was significantly (p < 0.05) shorter in shift workers than in day workers. Simple linear regression revealed that the MEQ score, sleep duration on the day shift and current work shift (i.e. rotating shift work) were significantly (p < 0.05) associated with the CES-D score. Multivariate linear regression indicated that greater eveningness and shorter sleep duration were independently associated with higher CES-D scores, while rotating shift work was not. These associations between the MEQ score, the sleep duration and the CES-D score were also confirmed in both day workers and shift workers when the groups were analyzed separately. These results suggest that greater eveningness and shorter sleep duration on the day shift were independently associated with higher levels of depressive symptoms, which may explain associations between rotating shift workers and depressive symptoms. These findings have important implications for the development of novel strategies for preventing poor mental health in day workers and rotating shift workers.

Accelerometer-Based Monitoring of Upper Limb Movement in Older Adults With Acute and Subacute Stroke.

Background and Purpose:Use of the affected extremity during daily life is important if disuse atrophy is to be prevented after stroke. This study examined whether objectively measured real-world upper limb movement is associated with the amount of use of the affected upper limb, as assessed by a standardized assessment tool in older adults with acute or subacute stroke. This study also examined whether the real-world upper limb movement is associated with the extent of impairment of upper and lower extremities. Methods:The participants were 19 older adults with hemiparesis from acute or subacute stroke [17 (7) days after the stroke]. All the participants wore 3 accelerometers—1 on each wrist (bilateral accelerometry) and 1 on the waist—throughout a 24-hour period. They were interviewed about use of their upper limb in the real-world setting using a Motor Activity Log. Functions of the affected upper limb or upper and lower limbs were assessed using the National Institute of Health Stroke Scale, the Brunnstrom Recovery Stage (BRS), the Simple Test for Evaluating Hand Function, and the Functional Independence Measure tests. Results and Discussion:Movement counts measured with the wrist accelerometer on the affected upper limb (unilateral accelerometry) over 24 hours and during the 12-hour daytime period (08:00 to 20:00) were significantly correlated with scores for affected upper limb use (the Motor Activity Log) and functions (the upper extremity BRS and the affected side Simple Test for Evaluating Hand Function), upper and lower extremity functions (the National Institute of Health Stroke Scale, the lower extremity BRS, and the motor Functional Independence Measure), and step counts measured over the same period. To estimate the affected upper limb use or disuse, we subtracted the movement counts of the unaffected upper limb from those of the affected upper limb. As a result, the subtracted counts over 24 hours and during the 12-hour daytime period were only related to scores for affected upper limb use and functions. Conclusions:Bilateral accelerometry for monitoring upper limb movements in a real-world setting might be useful to clinicians for objective assessment of affected upper limb use or disuse and function among older adults with hemiparesis from acute or subacute stroke.

Associations between Diurnal 24-Hour Rhythm in Ambulatory Heart Rate Variability and the Timing and Amount of Meals during the Day Shift in Rotating Shift Workers

It has not hitherto been clarified whether there is an association between dietary behavior and circadian variation in autonomic nervous system activity among shift workers. This study examines diurnal 24-h rhythm in heart rate variability (HRV) and dietary behavior among rotating shift workers, while taking into account the sleep-wake cycle and physical activity. The subjects were 11 female and 2 male nurses or caregivers working in a rotating 2-shift system at a health care facility. All the subjects were asked to undergo 24-h electrocardiograph and step count recordings, and to record the time of each meal and the amounts of each food and beverage consumed. Coarse graining spectral analysis was used for approximately 10-min segments of HRV to derive the total power (TOT: >0.04 Hz) of the periodic components and the integrated power of periodic components in the low-frequency (LF: 0.04–0.15 Hz) and high-frequency (HF: >0.15 Hz) ranges. Then the ratio of HF power to TOT (HF nu) and the ratio of LF power to HF power (LF/HF) were calculated to assess cardiac vagal tone and cardiac sympathovagal balance, respectively. Single cosinor analysis was used to obtain 24-h period variations in both variables of HRV. Acrophases of HF nu and LF/HF expressed in time since awakening were significantly (p<0.05) delayed for subjects having breakfast at a later time after awakening. Multivariable regression analysis indicated that the timing of breakfast, the ratio of energy intake at dinner to total energy intake, and total energy intake were correlated to the acrophases of HF nu and/or LF/HF. These results suggest that the phase angle between circadian variation in cardiac autonomic nervous system activity and the sleep-wake cycle may be associated with dietary behavior in shift workers.

Relationship between near-infrared spectroscopy, and subcutaneous fat and muscle thickness measured by ultrasonography in Japanese community-dwelling elderly

Aim:  Near‐infrared spectroscopy (NIRS) allows estimation of the percentage of body fat (%BF) regardless of the patients posture; thus, it is useful for assessment of elderly patients with severe decline of basic activity who cannot hold a standing position. However, the accuracy by which the near‐infrared light emitted from NIRS reflects subcutaneous tissue is unknown. The aim of this study was to assess how correctly NIRS reflects the subcutaneous fat and muscle thickness derived from ultrasonography in community‐dwelling elderly.