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Dive into the research topics where Satoko Iwasawa is active.

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Featured researches published by Satoko Iwasawa.


Journal of Occupational Health | 2009

Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island.

Satoko Iwasawa; Yuriko Kikuchi; Yuji Nishiwaki; Makiko Nakano; Takehiro Michikawa; Tazuru Tsuboi; Shigeru Tanaka; Takamoto Uemura; Ai Ishigami; Hiroshi Nakashima; Toru Takebayashi; Mitsuru Adachi; Akihiro Morikawa; Kouichi Maruyama; Shoji Kudo; Iwao Uchiyama; Kazuyuki Omae

Effects of SO2 on Respiratory System of Adult Miyakejima Resident 2 Years after Returning to the Island: Satoko Iwasawa, et al. Department of Preventive Medicine and Public Health, School of Medicine, Keio University


Preventive Medicine | 2008

Gender difference in the relationships between vision and hearing impairments and negative well-being.

Sei Harada; Yuji Nishiwaki; Takehiro Michikawa; Yuriko Kikuchi; Satoko Iwasawa; Makiko Nakano; Ai Ishigami; Hideyuki Saito; Toru Takebayashi

OBJECTIVES To evaluate the association of hearing impairment, vision impairment and their combination (dual sensory impairment) with negative well-being such as depression, subjective poor health and the reduced functional ability in community-dwelling older adults, and to determine whether any association varies by gender. METHODS Between 2005 and 2006, we objectively examined vision and hearing impairment (using best-corrected visual acuity and pure-tone audiometric test) in 843 people aged 65 years and older (351 males, 492 females) in a rural Japanese town. Through a home visit interview survey using a structured questionnaire, we also collected information on depression (the five-item Geriatric Depression Scale), subjective poor health, and reduced functional activity (the Tokyo Metropolitan Institute of Gerontologys Index of Competence). RESULTS We observed gender differences in the association between sensory impairment and depression. Multiple logistic regression analysis revealed that hearing impairment in males (adjusted odds ratio: 2.22, 95% confidence interval; 1.07-4.61) and vision impairment in females (1.91, 1.14-3.21) were related to depression. Vision impairment and dual sensory impairment were also associated with subjective poor health and reduced functional activity in both sexes. CONCLUSIONS Sensory impairment is significantly associated with negative well-being in older persons, and its association with depression may differ between males and females.


Movement Disorders | 2011

Camptocormia in Japanese patients with Parkinson's disease: a multicenter study.

Morinobu Seki; Kazushi Takahashi; Atsuo Koto; Ban Mihara; Yoko Morita; Kazuo Isozumi; Kouichi Ohta; Kazuhiro Muramatsu; Jun Gotoh; Keiji Yamaguchi; Yutaka Tomita; Hideki Sato; Yoshihiro Nihei; Satoko Iwasawa; Norihiro Suzuki

The aim of this work was to investigate the prevalence of camptocormia and the clinical characteristics of patients with camptocormia in a large population of PD patients.


Journals of Gerontology Series A-biological Sciences and Medical Sciences | 2009

Serum Levels of Retinol and Other Antioxidants for Hearing Impairment Among Japanese Older Adults

Takehiro Michikawa; Yuji Nishiwaki; Yuriko Kikuchi; Kanae Hosoda; Kunio Mizutari; Hideyuki Saito; Keiko Asakura; Ai Milojevic; Satoko Iwasawa; Makiko Nakano; Toru Takebayashi

BACKGROUND The objective of this study was to assess the relation between serum levels of retinol and other antioxidants and hearing impairment in Japanese older adults. METHODS This is a community-based cross-sectional study comprising 762 residents aged 65 years or older in Kurabuchi, Gumma, Japan. We measured serum retinol and other antioxidants (alpha- and gamma-tocopherols, and carotenoids including beta-cryptoxanthin, alpha- and beta-carotenes, lycopene, and lutein plus zeaxanthin) by high-performance liquid chromatography and divided each measurement into quartiles. Hearing impairment was defined as a failure to hear a 30-dB hearing level (HL) signal at 1 kHz and a 40-dB HL signal at 4 kHz in the better ear in pure-tone audiometric tests. The odds ratios (OR) for hearing impairment were calculated for each of the upper three quartiles of retinol and other antioxidant levels relative to the lowest quartile. RESULTS Crude analysis showed that serum levels of retinol and provitamin A carotenoids (beta-cryptoxanthin, and alpha- and beta-carotenes) were inversely related to the prevalence of hearing impairment. The multiadjusted ORs (95% confidence intervals) for the highest quartile of retinol and the provitamin A family (combinations of provitamin A carotenoids) compared with the lowest were 0.51 (0.26-1.00) and 0.53 (0.27-1.02), respectively. A dose-response relationship was observed for retinol (p = .03) and provitamin A (p = .09). CONCLUSION Increased serum levels of retinol and provitamin A carotenoids were clearly associated with a decreased prevalence of hearing impairment.


Journal of Epidemiology | 2009

Lifestyle Factors and Visible Skin Aging in a Population of Japanese Elders

Keiko Asakura; Yuji Nishiwaki; Ai Milojevic; Takehiro Michikawa; Yuriko Kikuchi; Makiko Nakano; Satoko Iwasawa; Greg George Hillebrand; Kukizo Miyamoto; Masaji Ono; Yoshihide Kinjo; Suminori Akiba; Toru Takebayashi

Background The number of studies that use objective and quantitative methods to evaluate facial skin aging in elderly people is extremely limited, especially in Japan. Therefore, in this cross-sectional study we attempted to characterize the condition of facial skin (hyperpigmentation, pores, texture, and wrinkling) in Japanese adults aged 65 years or older by using objective and quantitative imaging methods. In addition, we aimed to identify lifestyle factors significantly associated with these visible signs of aging. Methods The study subjects were 802 community-dwelling Japanese men and women aged at least 65 years and living in the town of Kurabuchi (Takasaki City, Gunma Prefecture, Japan), a mountain community with a population of approximately 4800. The facial skin condition of subjects was assessed quantitatively using a standardized facial imaging system and subsequent computer image analysis. Lifestyle information was collected using a structured questionnaire. The association between skin condition and lifestyle factors was examined using multivariable regression analysis. Results Among women, the mean values for facial texture, hyperpigmentation, and pores were generally lower than those among age-matched men. There was no significant difference between sexes in the severity of facial wrinkling. Older age was associated with worse skin condition among women only. After adjusting for age, smoking status and topical sun protection were significantly associated with skin condition among both men and women. Conclusions Our study revealed significant differences between sexes in the severity of hyperpigmentation, texture, and pores, but not wrinkling. Smoking status and topical sun protection were significantly associated with signs of visible skin aging in this study population.


BMC Geriatrics | 2009

Gender-specific associations of vision and hearing impairments with adverse health outcomes in older Japanese: a population-based cohort study

Takehiro Michikawa; Yuji Nishiwaki; Yuriko Kikuchi; Makiko Nakano; Satoko Iwasawa; Keiko Asakura; Ai Milojevic; Kunio Mizutari; Hideyuki Saito; Susumu Ishida; Tomonori Okamura; Toru Takebayashi

BackgroundSeveral epidemiological studies have shown that self-reported vision and hearing impairments are associated with adverse health outcomes (AHOs) in older populations; however, few studies have used objective sensory measurements or investigated the role of gender in this association. Therefore, we examined the association of vision and hearing impairments (as measured by objective methods) with AHOs (dependence in activities of daily living or death), and whether this association differed by gender.MethodsFrom 2005 to 2006, a total of 801 residents (337 men and 464 women) aged 65 years or older of Kurabuchi Town, Gunma, Japan, participated in a baseline examination that included vision and hearing assessments; they were followed up through September 2008. Vision impairment was defined as a corrected visual acuity of worse than 0.5 (logMAR = 0.3) in the better eye, and hearing impairment was defined as a failure to hear a 30 dB hearing level signal at 1 kHz in the better ear. Information on outcomes was obtained from the town hall and through face-to-face home visit interviews. We calculated the risk ratios (RRs) of AHOs for vision and hearing impairments according to gender.ResultsDuring a mean follow-up period of 3 years, 34 men (10.1%) and 52 women (11.3%) had AHOs. In both genders, vision impairment was related to an elevated risk of AHOs (multi-adjusted RR for men and women together = 1.60, 95% CI = 1.05-2.44), with no statistically significant interaction between the genders. In contrast, a significant association between hearing impairment and AHOs (multi-adjusted RR = 3.10, 95% CI = 1.43-6.72) was found only in the men.ConclusionIn this older Japanese population, sensory impairments were clearly associated with AHOs, and the association appeared to vary according to gender. Gender-specific associations between sensory impairments and AHOs warrant further investigation.


Occupational and Environmental Medicine | 2008

Volcanic sulfur dioxide and acute respiratory symptoms on Miyakejima island

A Ishigami; Yuriko Kikuchi; Satoko Iwasawa; Yuji Nishiwaki; Toru Takebayashi; Shigeru Tanaka; Kazuyuki Omae

Objectives: Following a volcanic eruption in 2000, high concentrations of ambient sulfur dioxide (SO2) are still observed on Miyakejima, Japan despite the reversal 2 years ago of the ban on residents living on the island. This study examines the association between current levels of volcanic SO2 and the incidence of acute subjective symptoms in volunteers on Miyakejima. Methods: The authors conducted a follow-up study on 611 healthy volunteers, on a person-hour basis (28 413 person-hours), who visited the island to provide support to residents from February to July 2005. Adverse health symptoms were measured by self-administered diary and exposure was approximated using monitoring data across 14 sites. Associations between incidence rates and increasing SO2 levels (reference (the lowest), very low, low, middle and high) were examined using Poisson regression. Results: Hourly incidence of cough, scratchy throat, sore throat and breathlessness showed clear exposure–response relationships with SO2 concentrations. There were statistically significant risks of those symptoms at relatively low SO2 levels. Thus, rate ratios in the 0.6-2.0 ppm exposure band (vs <0.01 ppm) were: for cough, 3.4 (95% CI 1.8 to 6.6) in men and 9.8 (3.9 to 24.9) in women; for sore throat, 3.2 (1.7 to 6.2) in men and 5.8 (2.0 to 16.5) in women; and for breathlessness, 10.5 (4.2 to 26.6) in men and 18.5 (4.6 to 74.3) in women. Little evidence of SO2 effects on sputum and nasal discharge/congestion was observed in this study. Eye and skin irritations showed inconsistent results between hourly maximal and hourly mean SO2 concentrations. Conclusion: The authors observed strong evidence of an exposure–response relationship between volcanic SO2 and subjective acute respiratory symptoms among a healthy population on Miyakejima. The results are consistent with reports that females and non-smokers are more sensitive to irritant gas than males and smokers, respectively.


American Journal of Geriatric Psychiatry | 2012

Higher Serum Dehydroepiandrosterone Sulfate Levels Are Protectively Associated with Depressive Symptoms in Men, But Not in Women: A Community-Based Cohort Study of Older Japanese

Takehiro Michikawa; Yuji Nishiwaki; Makiko Nakano; Satoko Iwasawa; Mutsuko Yamada; Keiko Asakura; Noriyuki Yoshioka; Erika Kuwahara; Toru Takebayashi

OBJECTIVE Dehydroepiandrosterone sulfate (DHEAS) appears to have a protective effect against depression, but evidence from prospective cohort studies is sparse. Therefore, we examined the association between serum DHEAS levels and depressive symptoms in older community-dwelling Japanese. DESIGN A community-based cohort study. SETTING Kurabuchi Town, Gunma Prefecture, Japan. PARTICIPANTS A total of 554 residents (248 men and 306 women) age 65 years or older without depressive symptoms at baseline. MEASUREMENTS We performed a baseline examination of the subjects between 2005 and 2006 to determine serum DHEAS levels. The subjects were categorized into three groups based on age strata- and sex-specific tertiles of DHEAS. Depressive symptoms were assessed with the Geriatric Depression Scale 15-item version (GDS-15) in face-to-face home visit interviews carried out once in 2007 and once in 2008. The association of DHEAS with depressive symptoms (GDS-15 ≥ 6) was analyzed with the use of logistic regression models. RESULTS The incidence of depressive symptoms was 12.1% in men and 19.6% in women. In men, the multiadjusted odds ratio of depressive symptoms was 0.24 (95% confidence interval: 0.06-0.94, Wald χ2 = 4.20, degrees of freedom = 1, p = 0.04) for the highest tertile compared with the lowest. The association observed for the highest versus the lowest remained significant even after adjustment for physical performance and cognitive function. In women, DHEAS was not associated with depressive symptoms. CONCLUSIONS In this study, higher serum DHEAS levels were found to be protectively and independently associated with the risk of developing depressive symptoms in men, but not in women.


Journals of Gerontology Series A-biological Sciences and Medical Sciences | 2013

Spinal Posture in the Sagittal Plane Is Associated With Future Dependence in Activities of Daily Living: A Community-Based Cohort Study of Older Adults in Japan

Kojiro Kamitani; Takehiro Michikawa; Satoko Iwasawa; Norihito Eto; Taichiro Tanaka; Toru Takebayashi; Yuji Nishiwaki

BACKGROUND Accumulated evidence shows how important spinal posture is for aged populations in maintaining independence in everyday life. However, the cross-sectional designs of most previous studies prevent elucidation of the relationship between spinal posture and future dependence in activities of daily living (ADL). We tried to clarify the association by measuring spinal posture noninvasively in a community-based prospective cohort study of older adults, paying particular attention to thoracic curvature, lumbar curvature, sacral hip angle, and inclination to determine which parameter is most strongly associated with dependence in ADL. METHODS Spinal posture was evaluated in 804 participants (338 men, 466 women, age range: 65-94 years) who were independent in ADL at baseline. We defined dependence in ADL as admission to a nursing home or need of home assistance. During the 4.5-year follow-up period, 126 (15.7%) participants became dependent in ADL. The relationship between the spinal posture parameters and outcome was assessed by dividing the participants into sex-specific quartiles of the parameters. RESULTS Only inclination (angle subtended between the vertical and a line joining C7 to the sacrum) was associated with outcome, although lumbar curvature also showed a marginal association. The age- and sex-adjusted odds ratio for a 1 unit increase in the quartiles of inclination was 1.79 (confidence interval: 1.44, 2.23). After mutual adjustment for the 4 parameters, statistical significance for inclination still remained, with no substantial changes in the association estimates. CONCLUSIONS This study indicates that spinal inclination is associated with future dependence in ADL among older adults.


Dementia and geriatric cognitive disorders extra | 2014

Screening for Impaired Cognitive Domains in a Large Parkinson's Disease Population and Its Application to the Diagnostic Procedure for Parkinson's Disease Dementia

Kouichi Ohta; Kazushi Takahashi; Jun Gotoh; Keiji Yamaguchi; Morinobu Seki; Yoshihiro Nihei; Satoko Iwasawa; Norihiro Suzuki

Background: Dementia is a new focus of research on improved treatment for Parkinsons disease (PD). In 2007, a screening tool for PD dementia (PD-D) was developed by the Movement Disorder Society (Level I testing), which still requires verification by a large population study. Methods: We conducted a cross-sectional and multicenter study including 13 institutions administering the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) to 304 PD patients (mean age: 70.6 ± 8.3 years; mean Hoehn and Yahr stage: 2.7 ± 0.7). Results: In all, 34.5% of the patients had MMSE scores <26; 94.3% of these patients had impairments in ≥2 cognitive domains and met the criteria for probable PD-D by Level I testing. Executive dysfunction combined with attention and memory impairment was most common (51.4%). In the Level I subtests of executive function, the score for phonemic fluency declined by <50% in patients with high MoCA scores (24-30 points) and lacked specificity for PD-D. No patient had visuospatial impairment (measured by the pentagon copying subtest) alone, and the score for pentagon copying stayed at ≥70% even in patients with low MMSE scores (12-25 points), therefore lacking sensitivity for PD-D. Conclusions: Level I testing with administration of the MMSE and MoCA is a practical and efficient screening tool for PD-D. However, the phonemic fluency and pentagon copying tests should be replaced by more specific/sensitive ones when screening for PD-D.

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Takehiro Michikawa

National Institute for Environmental Studies

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