J Iwamoto

Tenri University, Nara, Nara, Japan

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Publications (49)158.03 Total impact

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    ABSTRACT: In contrast with randomized controlled trials, observational studies have suggested that physiological levels of melatonin are reduced in patients with dementia or depression but the relationship has not been evaluated in large populations. To determine the relationships between physiological levels of melatonin and cognitive function and depressive symptoms. A cohort of 1105 community-dwelling elderly individuals was enrolled in this cross-sectional study (mean age, 71.8 ± 7.1 years). Urinary 6-sulfatoxymelatonin excretion (UME) and Mini-Mental State Examination (MMSE, n=935) and Geriatric Depression Scale (GDS, n=1097) scores were measured as indices of physiological melatonin levels, cognitive function, and depressive symptoms, respectively. With increases in UME quartiles, prevalence of cognitive impairment (MMSE score ≤26) and depressed mood (GDS score ≥6) significantly decreased (P for trend=0.003 and 0.012, respectively). In multivariate logistic regression models, after adjusting for confounders such as age, gender, socioeconomic status, physical activity, and sleep/wake cycles, higher UME levels were significantly associated with lower odds ratios (ORs) for cognitive impairment and depressed mood (ORs: Q1=1.00; Q2=0.88 and 0.76; Q3=0.66 and 0.85; Q4=0.67 and 0.53; P for trend=0.023 and 0.033, respectively). In addition, the highest UME group showed a significantly lower OR for depressed mood than the lowest UME group (Q4 vs. Q1: OR, 0.53, 95% confidence interval, 0.32-0.89, P=0.033). UME levels above the median value were significantly associated with a lower OR for cognitive impairment, even after further adjustment for depressive symptoms (OR=0.74; 95% confidence interval, 0.55-0.99; P=0.043). Significant associations of higher physiological melatonin levels with lower prevalence of cognitive impairment and depressed mood were revealed in a large general elderly population. The association between physiological melatonin levels and cognitive function was independent of depressive symptoms.
    Full-text · Article · Jun 2015 · The Journal of Clinical Endocrinology and Metabolism
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    ABSTRACT: Background: Melatonin is associated with a variety of diseases in advanced age, including insomnia, depression, and dementia, and its secretion is influenced by light exposure. Although studies in young and middle-aged subjects have shown that females tend to have higher melatonin levels than males, gender differences in melatonin levels among older people remain unclear. Methods: To determine the gender differences in melatonin levels among older people in home settings, we conducted a cross-sectional study in 528 older people. We measured overnight urinary 6-sulfatoxymelatonin excretion (UME; an index of melatonin secretion), and ambulatory light intensity. Results: The mean age of females was 1.8 years younger, and average intensity of daytime light exposure was half that in males (P < 0.01). In a univariate comparison, UME was significantly lower in females than in males (P < 0.01). A multivariate model using analysis of covariance showed that log-transformed UME remained significantly lower in females after adjustment for potential confounding factors, including age and daytime and nighttime light exposure profiles (males vs. females: 1.90 vs. 1.73 log µg; adjusted mean difference 0.17 log µg [95% confidence interval [CI] 0.02-0.32]; P = 0.02). This result indicates that older females have 18.4% (95% CI, 2.2-37.4%) lower UME than older males. Conclusions: Older females have significantly lower UME than older males, an association which is independent of light exposure profiles in home settings. Our findings may be useful as basic data for further research to investigate gender differences in several diseases associated with melatonin in the elderly.
    Full-text · Article · Sep 2014 · Journal of Epidemiology
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    ABSTRACT: AimThe present study investigated whether physical performance and musculoskeletal pain (MSP) are associated with self-perceived hearing handicap (HH) among high-functioning older adults.Methods We analyzed a total of 3982 community-dwelling high-functioning older adults (age 65 years and older). HH was assessed using the Hearing Handicap Inventory for Elderly-Screening. Self-reported hearing impairment (HI) was evaluated using a single question. We measured handgrip strength, walking speed (WS) and standing balance for assessments of physical performance. The severity of MSP assessed by interviews took into account its duration, limitation of daily activity and frequency.ResultsThe prevalence of HH and HI in our sample was 22.2% and 28.1%, respectively. After adjusting for other two physical performance measures, MSP, sex, age, education, marital status, risk factors for hearing loss, instrumental activity of daily living, depression, cognitive function and self-reported HI, the odds ratios for HH in the second fastest, the second slowest, and the slowest WS quartile were 1.14 (95% CI = 0.81–1.58), 1.29 (95% CI = 0.92–1.79), and 1.58 (95% CI = 1.11–2.23), respectively, compared with the fastest WS quartile. A significant dose–response relationship was found between slower WS and HH (P for trend = 0.01). No significant association with HH was found in handgrip strength, standing balance and MSP.ConclusionWS is associated with self-perceived HH in high-functioning older adults. The present study suggests that exercise programs to improve walking ability might be effective in preventing HH of self-sustainable older adults. Geriatr Gerontol Int 2014; ●●: ●●–●●.
    No preview · Article · Sep 2014 · Geriatrics & Gerontology International
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    ABSTRACT: Background: Higher cardiovascular mortality in winter may be partly explained by increased blood pressure (BP) because of cold exposure. However, this winter excess mortality is higher in countries with moderate winter than those with severe winter climate. Objectives: Although higher BP in low outdoor temperatures has been reported, the magnitude of association of indoor temperature with ambulatory BP remained unclear. We aimed to compare the associations of indoor and outdoor temperature with ambulatory BP. Methods: From repeated measurements on two consecutive days during colder months (October-April) among 868 elderly individuals, we assessed the association of indoor and outdoor temperatures with ambulatory BP using multilevel analysis with random intercept for each individual. Results: Correlation between indoor and outdoor temperature got weak along with decreasing outdoor temperature. Outdoor temperature was not significantly associated with ambulatory BP. In contrast, a 1 degrees C lower indoor temperature was significantly associated with 0.22 mmHg higher daytime SBP, 0.18% higher nocturnal BP fall, 0.34mmHg higher sleep-trough morning BP surge independent of potential confounders including physical activity. The models with indoor temperature showed better fit of the model than those with outdoor temperature. Night-time SBP did not show significant association with indoor and outdoor temperature but with bed temperature. Discussion: Our results suggest the importance to assess the association of indoor temperature with cardiovascular mortality to determine whether improving housing thermal environment reduces winter excess mortality. Conclusion: Indoor temperature showed stronger association than outdoor temperature with BP in colder months.
    No preview · Article · Jun 2014 · Journal of Hypertension
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    ABSTRACT: Background: Very few studies have investigated the association between diabetes and impaired health-related quality of life (HRQOL) in older adults, independent of chronic conditions and geriatric syndromes. Methods: We conducted a self-administered questionnaire survey and structured interviews with 3946 people aged 65 years or older to obtain medical histories of diabetes, chronic conditions, and geriatric syndromes. Blood tests were performed to measure glycated hemoglobin (HbA1c) and plasma glucose levels. HRQOL was evaluated using the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36), and multiple logistic regression analysis was used to calculate adjusted odds ratios and 95% CIs for low HRQOL. Results: A total of 3521 participants had not received a physician diagnosis of diabetes. Of these, 2345 participants with an HbA1c less than 5.7% were defined as the referent group. As compared with the referent group, 1029 participants with an HbA1c of at least 5.7% but less than 6.5% showed no significant decrease in QOL on the SF-36 physical, mental, and role component summaries, after adjustment for chronic conditions, geriatric syndromes, and other potential confounders. However, 572 patients who had received a physician diagnosis of diabetes and/or had an HbA1c of 6.5% or higher had a significantly higher adjusted odds ratio (1.48; 95% CI, 1.18-1.84) for the low physical component summary. No significant differences in relation to glycemic control, treatment regimen, or diabetes duration were found in any of the 3 component summaries among the 425 participants who were undergoing diabetes treatment. Conclusions: Older Japanese adults with diabetes had decreased physical QOL, independent of chronic conditions and geriatric syndromes.
    Full-text · Article · May 2014 · Journal of Epidemiology
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    ABSTRACT: Circadian misalignment between internal and environmental rhythms dysregulates blood pressure (BP) variability because of disruption of the biological clock, resulting in increased nighttime BP. Although exposure to light-at-night is associated with the circadian misalignment, it remains unclear whether exposure to light-at-night in home settings is associated with nighttime BP. In this cross-sectional analysis of 528 elderly individuals (mean age: 72.8 years), we measured bedroom light intensity at 1-min intervals on two consecutive nights along with ambulatory BP, overnight urinary melatonin excretion and actigraphy. With regard to adjusted mean comparisons using analysis of covariance, the light-at-night group (average: ≥5 lux; n = 109) showed significantly higher nighttime systolic BP (SBP; adjusted mean: 120.8 vs. 116.5 mmHg, p = 0.01) and diastolic BP (70.1 vs. 67.1 mmHg, p < 0.01) compared with the Darker group (average: <5 lux; n = 419) independently of potential confounding factors including overnight urinary melatonin excretion and actigraphic sleep quality. We observed consistent associations between light-at-night and nighttime BP in different cutoff values for light-at-night intensity (i.e. 3 and 10 lux). In conclusion, exposure to light-at-night in home settings is significantly associated with increased nighttime BP in elderly individuals independently of overnight urinary melatonin excretion. A 4.3 mmHg increase in nighttime SBP is associated with a 6.1% increase in total mortality, which corresponds to approximately 10 000 annual excess deaths in Japanese elderly population.
    Full-text · Article · Mar 2014 · Chronobiology International
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    ABSTRACT: Higher morning blood pressure (BP) surge is a risk factor for cardiovascular disease independent of 24-h mean BP. Although low outdoor temperatures are associated with higher morning BP surges (MBPSs), the influence of indoor temperature and ambient temperatures (temperature while indoors or temperature while outdoors) on MBPS remains unclear. Such information may help prevent excess winter mortality. We simultaneously measured indoor temperatures (living room and bedroom), ambulatory BP and physical activity using wrist actigraphy for 768 person-days during winter and spring/fall in 192 participants (mean age, 69.9 years). Although the indoor and outdoor temperatures showed a strong correlation during periods of moderate temperature (range: 9.8 to 27.7 °C, rp=0.84), the correlation decreased during periods of lower outdoor temperatures (range: -3.37 to 9.73 °C, rp=0.28). In univariate and multivariate analyses, models with ambient temperatures showed the best goodness of fit (lowest Akaike's information criterion (AIC)) followed by models with indoor temperatures and those with outdoor temperatures (AIC: ambient<indoor<outdoor temperature). A multivariate linear mixed-effect regression model showed that a 1 °C decrease in the ambient temperature was significantly associated with a 0.44 mm Hg increase in the sleep-trough MBPS and a 0.52 mm Hg increase in the prewaking BP surge. This was independent of potential confounders, including physical activity.Journal of Human Hypertension advance online publication, 20 February 2014; doi:10.1038/jhh.2014.4.
    No preview · Article · Feb 2014 · Journal of human hypertension
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    ABSTRACT: Circadian misalignment between internal and environmental rhythms dysregulates glucose homeostasis because of disruption of the biological clock, and increases risk of diabetes. Although exposure to evening light and decreased melatonin secretion are both associated with the circadian misalignment, it remains unclear whether they are associated with diabetes. In this cross-sectional study on 513 elderly individuals (mean age, 72.7 years), we measured ambulatory light intensity during the 4 h prior to bedtime at 1-min intervals during two consecutive days and overnight urinary 6-sulfatoxymelatonin excretion (UME) along with glucose metabolism. The median average intensity of evening light exposure and UME were 25.4 lux (interquartile range 17.5-37.6) and 6.6 μg (interquartile range 3.9-9.7), respectively. Both log-transformed average intensity of evening light exposure and log-transformed UME were significantly associated with diabetes in a multivariate logistic regression model adjusted for covariates, including gender, body mass index, duration in bed, and night-time light exposure [adjusted odds ratio (OR), 1.72; 95% confidence interval (CI), 1.12-2.64; p = 0.01; and adjusted OR, 0.66; 95% CI, 0.44-0.97; p = 0.04; respectively]. An increase in evening light exposure from 17.5 to 37.6 lux (25-75th percentiles) was associated with a 51.2% (95% CI, 8.2-111.4%) increase in prevalent diabetes, and an increase in UME from 3.9 to 9.7 μg (25-75th percentiles) was associated with a 32.0% (95% CI, 1.9-52.8%) decrease in prevalent diabetes. In conclusion, this study in elderly individuals demonstrated that evening light exposure in home settings and UME were significantly and independently associated with diabetes.
    Full-text · Article · Dec 2013 · Chronobiology International
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    ABSTRACT: Objective Metabolic syndrome contains many risks for medical diseases such as cardiovascular disease and diabetes, which might precipitate depressive symptoms in the older people. However, the association between depressive symptoms and metabolic syndrome in Japanese community-dwelling older people is unclear. This study was performed to answer this important question. Methods Cross-sectional analyses were performed on 3796 community-dwelling independent older people (65years, 1911 men and 1885 women) from the 2007-2008 baseline examination of the Fujiwara-kyo study, a prospective cohort study on successful aging. Depressive symptoms were assessed using the 15-item short form of the Geriatric Depression Scale and metabolic syndrome was defined according to the 2005 International Diabetes Federation. Covariates were social supports, negative life events, health behavior, education, cognitive function, anthropometric status, and others. Multiple logistic regression analyses were performed to determine the relationships between depressive symptoms and these variables. ResultsThe prevalence of depressive symptoms (Geriatric Depression Scale-15 6) and metabolic syndrome were 14.8% and 16.6%, respectively. Significant protective factors against depressive symptoms were higher education, more opportunity for drinking of alcohol, better social supports, and more walking daily. Metabolic syndrome was statistically associated with depressive symptoms (adjusted odds ratio=1.32, 95% confidence interval=1.03-1.68). Other risk factors significantly associated with depressive symptoms were sleep disturbance, visual or hearing impairment, and negative life events. Conclusions The present study showed an association between metabolic syndrome and depressive symptoms in ambulatory Japanese older people, as in western countries.
    No preview · Article · Dec 2013 · International Journal of Geriatric Psychiatry
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    ABSTRACT: Epidemiologic data have demonstrated associations of sleep-onset insomnia with a variety of diseases, including depression, dementia, diabetes and cardiovascular diseases. Sleep initiation is controlled by the suprachiasmatic nucleus of the hypothalamus and endogenous melatonin, both of which are influenced by environmental light. Exposure to evening light is hypothesized to cause circadian phase delay and melatonin suppression before bedtime, resulting in circadian misalignment and sleep-onset insomnia; however, whether exposure to evening light disturbs sleep initiation in home settings remains unclear. In this longitudinal analysis of 192 elderly individuals (mean age: 69.9 years), we measured evening light exposure and sleep-onset latency for 4 days using a wrist actigraph incorporating a light meter and an accelerometer. Mixed-effect linear regression analysis for repeated measurements was used to evaluate the effect of evening light exposure on subsequent sleep-onset latency. The median intensity of evening light exposure and the median sleep-onset latency were 27.3 lux (interquartile range, 17.9-43.4) and 17 min (interquartile range, 7-33), respectively. Univariate models showed significant associations between sleep-onset latency and age, gender, daytime physical activity, in-bed time, day length and average intensity of evening and nighttime light exposures. In a multivariate model, log-transformed average intensity of evening light exposure was significantly associated with log-transformed sleep-onset latency independent of the former potential confounding factors (regression coefficient, 0.133; 95% CI, 0.020-0.247; p = 0.021). Day length and nighttime light exposure were also significantly associated with log-transformed sleep-onset latency (p = 0.001 and p < 0.001, respectively). In conclusion, exposure to evening light in home setting prolongs subsequent sleep-onset latency in the elderly.
    Full-text · Article · Oct 2013 · Chronobiology International
  • J Iwamoto · Y Sato · H Matsumoto
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    ABSTRACT: The objective of the present study was to clarify the relationships between physical function, bone mass, biochemical markers, renal function, and a history of nonvertebral fracture in postmenopausal women with osteoporosis. In total, 143 postmenopausal women with osteoporosis (mean age: 71.2 years) and an osteoporosis treatment-naïve status were recruited. Twenty-seven women had a history of nonvertebral fracture (nonvertebral fracture group) and 116 women did not (control group). The patients' bone mass, biochemical markers, estimated glomerular filtration rate (eGFR), unipedal standing time (index of body balance), and the five-repetition chair-rising time (index of muscle power) were compared between the two groups. Age, body mass index, bone mass, serum alkaline phosphatase, creatinine, albumin, urinary cross-linked N-terminal telopeptides of type I collagen, eGFR, and the unipedal standing time did not differ significantly between the two groups. However, the chair-rising time was significantly longer (12.3 sec vs. 9.6 sec) in the nonvertebral fracture group than in the control group. The odds ratio (95% confidence intervals) for nonvertebral fractures in subjects with a chair-rising time >10.1 sec (mean value) was 4.28 (1.78, 10.30). Thus, a significant association was found between the impairment of muscle power and a history of nonvertebral fracture in postmenopausal women with osteoporosis.
    No preview · Article · Sep 2013 · Journal of musculoskeletal & neuronal interactions
  • Y Sato · Y Honda · J Iwamoto · N Amano
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    ABSTRACT: Objectives: Minodronate is a nitrogen-containing bisphosphonate that is commercially available for the treatment of osteoporosis in Japan. Preclinical studies demonstrated that minodronate is at least 10 times more potent than alendronate in inhibiting bone resorption in vivo. A high incidence of fractures, particularly of the hip, represents an important problem in Alzheimer disease (AD) patients who are prone to falls and may have osteoporosis. Methods: A total of 256 elderly patients with AD were assigned to daily treatment with 1.0 mg of minodronate or a daily treatment with risedronate combined with daily 1000 IU ergocalciferol and 1200 mg elemental calcium, and followed up for 12 months. Results: At baseline, patients of both groups showed low 25-hydroxyvitamin D with compensatory hyperparathyroidism. Non-vertebral fractures occurred in 5 patients in the minodronate group and 7 patients in the risedronate group (5 hip fractures; one fracture each at the distal forearm and pelvis). There was no difference in risk of hip fracture between the two groups (p=.70; odds ratio=0.8). Conclusions: The study medications were well tolerated with relatively few adverse events and were equivalent in reducing the risk of a fracture in elderly patients with AD.
    No preview · Article · Sep 2013 · Journal of musculoskeletal & neuronal interactions
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    ABSTRACT: Recent advances in understanding the fundamental links between chronobiology and depressive disorders have enabled exploring novel risk factors for depression in the field of biological rhythms. Increased exposure to light at night (LAN) is common in modern life, and LAN exposure is associated with circadian misalignment. However, whether LAN exposure in home settings is associated with depression remains unclear. We measured the intensities of nighttime bedroom light and ambulatory daytime light along with overnight urinary melatonin excretion (UME) in 516 elderly individuals (mean age, 72.8). Depressive symptoms were assessed using the Geriatric Depression Scale. The median nighttime light intensity was 0.8lx (interquartile range, 0.2-3.3). The depressed group (n=101) revealed significantly higher prevalence of LAN exposure (average intensity, ≥5lx) compared with that of the nondepressed group (n=415) using a multivariate logistic regression model adjusted for daytime light exposure, insomnia, hypertension, sleep duration, and physical activity [adjusted odds ratio (OR): 1.89; 95% confidence interval (CI), 1.10-3.25; P=0.02]. Consistently, another parameter of LAN exposure (duration of intensity ≥10lx, ≥30min) was significantly more prevalent in the depressed than in the nondepressed group (adjusted OR: 1.71; 95% CI, 1.01-2.89; P=0.046). In contrast, UME was not significantly associated with depressive symptoms. Cross-sectional analysis. These results suggested that LAN exposure in home settings is significantly associated with depressive symptoms in the general elderly population. The risk of depression may be reduced by keeping nighttime bedroom dark.
    Full-text · Article · Jul 2013 · Journal of Affective Disorders
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    ABSTRACT: Although oral melatonin administration may enhance a nocturnal blood pressure fall, it remains unclear whether endogenous melatonin, which is present at considerably lower levels than pharmacological melatonin, is associated with the non-dipper pattern. The present cross-sectional study aimed to determine the association between urinary melatonin excretion, an index of endogenous melatonin, and the non-dipper pattern. We measured the following variables in 141 elderly hypertensives: overnight urinary melatonin excretion, ambulatory blood pressure and actigraphic physical activity. We defined a non-dipper pattern as a <10% fall in sleep systolic blood pressure compared with awake systolic blood pressure. When participants were divided into two groups (high and low melatonin groups) by the cutoff value for identifying the top tertile, the characteristics, except for age, did not significantly differ between the two groups. Crude logistic regression analysis showed significant associations of the non-dipper pattern with age, diabetes, higher urinary melatonin excretion (high vs. low) and daytime activity. In a multivariate analysis after adjustment for age, diabetes and daytime activity, the odds ratio for the non-dipper pattern in the high melatonin group was significantly lower than that in the low melatonin group (odds ratio: 0.39, 95% confidence interval (CI): 0.17-0.91, P=0.03). Moreover, the mean percentage systolic blood pressure nocturnal fall, adjusted for the former covariates, was significantly higher in the high melatonin group than the low melatonin group (difference 3.5%, 95% CI: 0.0-7.0%, P=0.048). Among elderly hypertensive individuals, nocturnal urinary melatonin excretion is significantly and inversely associated with the non-dipper pattern.Hypertension Research advance online publication, 11 April 2013; doi:10.1038/hr.2013.20.
    Full-text · Article · Apr 2013 · Hypertension Research
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    ABSTRACT: Background: Previous studies have proposed that higher blood pressure (BP) in winter is an important cause of increased mortality from cardiovascular disease during the winter. Some observational and physiological studies have shown that cold exposure increases BP, but evidence from a randomised controlled study assessing the effectiveness of intensive room heating for lowering BP was lacking. Objectives: The present study aimed to determine whether intensive room heating in winter decreases ambulatory BP as compared with weak room heating resulting in a 10°C lower target room temperature when sufficient clothing and bedclothes are available. Methods: We conducted a parallel group, assessor blinded, simple randomised controlled study with 1:1 allocation among 146 healthy participants in Japan from November 2009 to March 2010. Ambulatory BP was measured while the participants stayed in single experimental rooms from 21:00 to 8:00. During the session, participants could adjust the amount of clothing and bedclothes as required. Compared with the weak room heating group (mean temperature ± SD: 13.9 ± 3.3°C), systolic morning BP (mean BP 2 h after getting out of bed) of the intensive room heating group (24.2 ± 1.7°C) was significantly lower by 5.8 mm Hg (95% CI 2.4 to 9.3). Sleep-trough morning BP surges (morning BP minus lowest night-time BP) in the intensive room heating group were significantly suppressed to about two thirds of the values in the weak room heating group (14.3 vs 21.9 mm Hg; p<0.01). Conclusions: Intensive room heating decreased morning BP and the morning BP surge in winter.
    Full-text · Article · Feb 2013 · Journal of epidemiology and community health
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    ABSTRACT: Objectives: To investigate factors associated with activities of daily living in independently living elderly persons in a community. Subjects and methods: The potential subjects were 4,472 individuals aged 65 years and older who voluntarily participated in a large cohort study, the Fujiwara-kyo study. We used self-administered questionnaires consisting of an activities of daily living (ADL) questionnaire with the Physical Fitness Test established by the Ministry of Education, Culture, Sports, Science and Technology (12 ADL items) to determine the index of higher-level physical independence, demographics, Geriatric Depression Scale, and so on. Mini-mental state examination, measurement of physical fitness, and blood tests were also carried out. A lower ADL level was defined as having a total score of the 12 ADL items (range, 12-36 points) that was below the first quartile of a total score for all the subjects. Factors associated with a low ADL level were examined by multiple logistic regression. Results: A total of 4,198 remained as subjects for analysis. The male, female and 5-year-old groups showed significant differences in the median score of 12 ADL items between any two groups. The highest odds ratio among factors associated with lower ADL level by multiple logistic regression with mutually adjusted independent variables was 4.49 (95%CI: 2.82-7.17) in the groups of "very sharp pain" or "strong pain" during the last month. Low physical ability, self-awareness of limb weakness, a BMI of over 25, low physical activity, cerebrovascular disorder, depression, low cognitive function, unable "to see normally", unable "to hear someone", "muscle, bone and joint pain" were independently associated with lower ADL level. Conclusion: Multiple factors are associated with lower ADL level assessed on the basis of the 12 ADL items.
    No preview · Article · Jan 2013 · Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene)
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    ABSTRACT: Context:Obesity and exposure to light at night (LAN) have increased globally. Although LAN suppresses melatonin secretion and disturbs body mass regulation in experimental settings, its associations with melatonin secretion, obesity, and other metabolic consequences in uncontrolled home settings remain unclear.Objective:The aim of this study was to determine the association of exposure to LAN in an uncontrolled home setting with melatonin secretion, obesity, dyslipidemia, and diabetes.Design and Participants:A cross-sectional study was performed in 528 elderly individuals (mean age, 72.8 yr).Measures:The intensity of LAN in the bedroom was measured at 1-min intervals during two consecutive nights, along with overnight urinary melatonin excretion and metabolic parameters.Results:Compared with the Dim group (average <3 lux; n = 383), the LAN group (average ≥3 lux; n = 145) showed significantly higher body weight (adjusted mean, 58.8 vs. 56.6 kg; P = 0.01), body mass index (23.3 vs. 22.7 kg/m(2); P = 0.04), waist circumference (84.9 vs. 82.8 cm; P = 0.01), triglyceride levels (119.7 vs. 99.5 mg/dl; P < 0.01), and low-density lipoprotein cholesterol levels (128.6 vs. 122.2 mg/dl; P = 0.04), and showed significantly lower high-density lipoprotein cholesterol levels (57.4 vs. 61.3 mg/dl; P = 0.02). These associations were independent of numerous potential confounders, including urinary melatonin excretion. Furthermore, LAN exposure is associated with higher odds ratios (ORs) for obesity (body mass index: OR, 1.89; P = 0.02; abdominal: OR, 1.62; P = 0.04) and dyslipidemia (OR, 1.72; P = 0.02) independent of demographic and socioeconomic parameters. In contrast, urinary melatonin excretion and glucose parameters did not show significant differences between the two groups.Conclusions:Exposure to LAN in an uncontrolled home setting is associated with impaired obese and lipid parameters independent of nocturnal urinary melatonin excretion in elderly individuals. Moreover, LAN exposure is associated with higher ORs for obesity and dyslipidemia independent of demographic and socioeconomic parameters.
    Full-text · Article · Nov 2012 · The Journal of Clinical Endocrinology and Metabolism
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    ABSTRACT: Context:Melatonin is involved in a variety of diseases, including cancer, insomnia, depression, dementia, hypertension, and diabetes; its secretion is influenced by environmental light. Although daylight exposure increases nocturnal melatonin secretion in a controlled laboratory setting, whether it increases nocturnal melatonin secretion in an uncontrolled daily life setting remains unclear.Objective:We aimed to determine the association between daylight exposure in an uncontrolled daily life setting and urinary 6-sulfatoxymelatonin excretion.Design and Participants:A cross-sectional study was conducted in 192 elderly individuals (mean age, 69.9 yr).Measures:We measured ambulatory daylight exposure using a wrist light meter in two 48-h sessions; furthermore, we measured overnight urinary 6-sulfatoxymelatonin excretion, an index of melatonin secretion, on the second night of each session.Results:The median duration of daylight exposure of at least 1000 lux was 72 min (interquartile range, 37-124). Univariate linear regression analysis showed marginal to significant associations between log-transformed urinary 6-sulfatoxymelatonin excretion and age, current smoking status, benzodiazepine use, day length, log-transformed duration of daylight exposure of at least 1000 lux, and daytime physical activity. In a multivariate model, log-transformed duration of daylight exposure of at least 1000 lux was significantly associated with log-transformed urinary 6-sulfatoxymelatonin excretion (regression coefficient, 0.101; 95% confidence interval, 0.003-0.199; P = 0.043). Furthermore, an increase in the duration of daylight exposure of at least 1000 lux from 37 to 124 min (25th to 75th percentiles) was associated with a 13.0% increase in urinary 6-sulfatoxymelatonin excretion (6.8 to 7.7 μg).Conclusions:Daylight exposure in an uncontrolled daily life setting is positively associated with urinary 6-sulfatoxymelatonin excretion in the elderly.
    Full-text · Article · Sep 2012 · The Journal of Clinical Endocrinology and Metabolism
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    J Iwamoto · Y Sato · T Takeda · H Matsumoto
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    ABSTRACT: A randomized controlled trial was conducted to determine the effect of 6 months of whole body vibration (WBV) exercise on physical function in postmenopausal osteoporotic women treated with alendronate. Fifty-two ambulatory postmenopausal women with osteoporosis (mean age: 74.2 years, range: 51-91 years) were randomly divided into two groups: an exercise group and a control group. A four-minute WBV exercise was performed two days per week only in the exercise group. No exercise was performed in the control group. All the women were treated with alendronate. After 6 months of the WBV exercise, the indices for flexibility, body balance, and walking velocity were significantly improved in the exercise group compared with the control group. The exercise was safe and well tolerated. The reductions in serum alkaline phosphatase and urinary cross-linked N-terminal telopeptides of type I collagen during the 6-month period were comparable between the two groups. The present study showed the benefit and safety of WBV exercise for improving physical function in postmenopausal osteoporotic women treated with alendronate.
    Preview · Article · Sep 2012 · Journal of musculoskeletal & neuronal interactions
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    ABSTRACT: Purpose: Little is known about the usefulness of the Hearing Handicap Inventory for the Elderly-Screening (HHIE-S) and a single question (SQ) in assessing hearing impairment (HI) and the impact of HI on quality of life (QOL). The objective of this study was to examine the reliability, validity, and associations with QOL measures (i.e., subjective well-being, depressive symptoms, subjective loneliness, and physical functioning) of the HHIE-S and the SQ in the elderly community. Methods: A self-report questionnaire including HHIE-S, SQ, Philadelphia Geriatric Center Morale Scale, Geriatric Depression Scale, UCLA Loneliness Scale, and the Tokyo Metropolitan Institute of Gerontology Index of Competence was administered to community elderly (781 males and 950 females). Among them, 97 males and 100 females also responded voluntarily to a request for test-retest and auditory tests. The criterion validity was tested by using pure-tone averages. Results: Regarding the reliability of HHIE-S, Cronbach's alpha coefficient was 0.91, Spearman-Brown coefficient was 0.90, and intra-class correlation coefficient was 0.85. Regarding the test-retest reliability of SQ, kappa coefficient was 0.65. HHIE-S had significantly lower sensitivity in identifying >25-dB HI, but significantly higher specificity for the detection of >40-dB HI than SQ. HHIE-S had stronger associations with QOL measures than did SQ. Conclusions: HHIE-S had high reliability, while SQ had insufficient reliability. HHIE-S was more specific in detecting HI and more sensitive in assessing the impact of HI on QOL than SQ. HHIE-S is a more effective instrument for assessing HI and QOL research than SQ in the elderly community.
    No preview · Article · Jul 2012 · Quality of Life Research

Publication Stats

778 Citations
158.03 Total Impact Points

Institutions

  • 2012-2015
    • Tenri University
      Nara, Nara, Japan
  • 1999-2013
    • Keio University
      • • Institute for Integrated Sports Medicine
      • • Department of Orthopedic Surgery
      Edo, Tokyo, Japan
  • 2010-2012
    • Nara Medical University
      • Department of Community Health and Epidemiology
      Kashihara, Nara, Japan
  • 2011
    • Yokkaichi University
      Yokkaiti, Mie, Japan