Published papers

The objective of this study was to clarify the awareness and treatment status of hypertension in Japanese workers, comparing with those of hypercholesterolemia. The subjects were 6,186 workers (age 19 to 69 years), who worked at 12 workplaces in Japan and who continuously participated in the High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) study at the baseline (1999 or 2000) and the subsequent year (2000 or 2001). No Intervention was performed during the study period. Blood pressure and total cholesterol level were measured at baseline. Awareness and treatment status were examined by a self-administered questionnaire in the following year. Untreated subjects were defined as those were not aware of hypertension (or hypercholesterolemia) or those not taking medication and not undergoing lifestyle modification. The percentages of subjects with hypertension defined as aware were 65.7% in men and 72.7% in women, respectively. The percentages of subjects with hypercholesterolemia defined as aware were 55.7% in men and 58.6% in women, respectively. In subjects 40 years and older, the awareness rate for hypertension was significantly higher than the awareness rate for hypercholesterolemia (75.0% vs. 59.2%, p<0.001). The percentage of untreated subjects with hypertension was significantly lower than the percentage of untreated subjects with hypercholesterolemia (41.0% vs. 57.1%, p<0.001). Although Japanese workers ≥40 years old have a higher awareness of and are more often treated for hypertension than for hypercholesterolernia, there are still many unaware and untreated individuals with either disease in all age groups. It is important to increase the awareness of risk factors in individuals with positive findings for these conditions.

The "Just-in-Time system" improves productivity and efficiency through cost reduction while it makes workers work in a standing posture. The aim of this study was to investigate the prevalence of postural hypotension in females during prolonged standing work, and to discuss preventive methods. Twelve female static standing workers (mean age+/-standard deviation; 32+/-14 yr old), 6 male static standing workers (30+/-4 yr old), 10 female walking workers (27+/-7 yr old) and 9 female desk workers (31+/-5 yr old) in a certain telecommunications equipment manufacturing factory agreed to participate in this study. All participants received an interview with an occupational physician, and performed the standing up test before working and ambulatory blood pressure monitoring (ABPM) while working. Although the blood pressure of the standing up test did not differ among the groups, mean pulse rates on standing up significantly increased in every group. Hypotension rates in the female standing workers' group by ABPM were 9 persons of 12 participants (75%) for systolic blood pressure (SBP), and were 11 persons of 12 participants (92%) for diastolic blood pressure (DBP). There were significantly higher than those in the female desk workers' group, none of 9 participants (0%) for SBP and 2 of 9 participants (22%) for DBP. The hypotension rates both male standing and female walking worker groups did not differ. Because all 8 workers who were found to have postural hypotension by the standing up test had decreased SBP and/or DBP by ABPM, it is suggested that persons at high risk of postural hypotension during standing work could be screened by the standing up test. The mechanism of postural hypotension may be a decrease of venous return due to leg swelling, and neurocardiogenic or vasovagal response. Preventing the congestion of the lower limbs by walking, managing standing time and wearing elastic hose to keep the amount of the venous return could prevent postural hypotension during prolonged standing work.

Objectives: The rapid increase of mobile phone use has increased public concern about its possible health effects in Japan, where the mobile phone system is unique in the characteristics of its signal transmission. To examine Hie relation between mobile phone use and acoustic neuroma, a case-control study was initiated. Methods: The study followed the common, core protocol of the international collaborative study, INTERPHONE. A prospective case recruitment was done in Japan for 2000-04. One hundred and one acoustic neuroma cases, who were 30-69 years of age and resided in the Tokyo area, and 339 age, sex, and residency matched controls were interviewed using a common computer assisted personal interview system. Education and marital status adjusted odds ratio was calculated with a conditional logistic regression analysis. Results: Fifty one cases (52.6%) and 192 controls (58.2%) were regular mobile phone users on the reference date, which was set as one year before the diagnosis, and no significant increase of acoustic neuroma risk was observed, with the odds ratio (OR) being 0.73 (95% CI 0.43 to 1.23). No exposure related increase in the risk of acoustic neuroma was observed when the cumulative length of use (<4 years, 4-8 years, >8 years) or cumulative call time (<300 hours, 300-900 hours, >900 hours) was used as an exposure index. The OR was 1.09 (95% CI 0.58 to 2.06) when the reference date was set as five years before the diagnosis. Further, laterality of mobile phone use was not associated with tumours. Conclusions: These results suggest that there is no significant increase in the risk of acoustic neuroma in association with mobile phone use in Japan.

Objective: To evaluate exercise intervention efficacy for the prevention and treatment of sarcopenia in the elderly. Methods: We conducted a systematic literature search of randomized controlled trials in the Physical Activity Guidelines Advisory Committee Report (before 2007), Pubmed, the Cochrane database, and Igaku Chuo Zasshi (January 2006 to August 2009) Data Extraction: Two authors independently extracted relevant data. A total of 951 articles were found by search engines, and 9 studies were finally selected after a review by 2 experts. The content of these studies, especially duration, sets, periods, frequency, and intensity of exercise intervention were extracted and summarized in a results table. Five of 6 articles concluded that high-intensity resistance training significantly increased soft lean tissue and muscle mass. The remaining 3 articles indicated that moderate-intensity resistance training did not affect soft lean tissue or muscle mass. Conclusion: This systematic review suggested that high-intensity resistance training with sufficient periods, frequency, repetitions, and sets is effective to counteract the loss of muscle mass associated with advancing age.

Background: Prevalence of men with cardiometabolic risk factors (CMRF) is increasing in Japan. Few studies have comprehensively examined the relation between lifestyles and CMRF. Methods. We examined the baseline data from 3,498 male workers ages 19 to 69 years who participated in the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study at 12 large-scale companies throughout Japan. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). Dietary intake was surveyed by a semi-quantitative Food Frequency Questionnaire. We defined four CMRF in this study as follows: 1) high blood pressure (BP): systolic BP 130 mmHg, or diastolic BP ≥85 mmHg, or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration < 40 mg/dl, or triglycerides concentration ≥150 mg/dl, or on medication for dyslipidemia; 3) impaired glucose tolerance: fasting blood sugar concentration ≥110 mg/dl; 4) obese: a body mass index ≥25 kg/m 2. Results: Those who had 0 to 4 CMRF accounted for 1,597 (45.7%), 1,032 (29.5%), 587 (16.8%), 236 (6.7%), and 44 (1.3%) participants, respectively, in the Poisson distribution. Poisson regression analysis revealed that independent factors that contributed to the number of CMRF were age (b = 0.020, P < 0.01), IPAQ (b = -0.091, P < 0.01), alcohol intake (ml/day) (b = 0.001, P = 0.03), percentage of protein intake (b = 0.059, P = 0.01), and total energy intake (kcal)(b = 0.0001, P < 0.01). Furthermore, alcohol intake and its frequency had differential effects. Conclusions: Alcohol intake, percent protein and total energy intake were positively associated, whereas drinking frequency and IPAQ were inversely associated, with the number of CMRF. © 2011 Katano et al; licensee BioMed Central Ltd.

Objective: To estimate the prevalence and risk factors of dry eye disease (DED) in a rural setting in Japan. Design: Cross-sectional study. Participants: We included 3294 subjects, aged <40 years who were in the residential registry for Koumi town. Intervention: Subjects in a rural mountain area, Koumi town, completed questionnaires designed to detect dry eye diagnosis and risk factors. Main Outcome Measures: Clinically diagnosed DED was defined as the presence of a previous clinical diagnosis of DED by ophthalmologists or severe symptoms of DED (both dryness and irritation constantly or often). Current symptoms of DED and possible risk factors such as age, gender, educational history, smoking history, alcohol drinking history, height and weight, visual display terminal (VDT) use, and contact lens (CL) wear, and past/current history of certain common systemic diseases were the main outcome measures. We used logistic regression analysis to examine associations between DED and other demographic factors. Results: Of the 3294 eligible residents, 2791 residents (85%) completed the questionnaire. The percentage of women with a composite outcome of clinically diagnosed DED or severe symptoms (21.6%; 95% confidence interval [CI], 19.523.9) was higher than that of men (12.5%; 95% CI, 10.714.5; P<0.001). A low body mass index (BMI; odds ratio [OR], 2.07; 95% CI, 0.984.39), CL use (OR, 3.84; 95% CI, 1.4610.10), and hypertension (HT) (OR, 1.39; 95% CI, 0.942.06) were risk factors for DED in men. Use of a VDT (OR, 2.33; 95% CI, 1.124.85), CL use (OR, 3.61; 95% CI, 2.136.10), and myocardial infarction or angina were the risk factors (OR, 2.64; 95% CI, 1.514.62), whereas high BMI was a preventive factor (OR, 0.69; 95% CI, 0.481.01) for DED in women. Conclusions: Among a Japanese cohort, DED leading to a clinical diagnosis or severe symptoms is prevalent. Use of CLs was a common dry eye risk factor in both genders. The condition is more prevalent in men with low BMI, HT, and in women with myocardial infarction or angina and VDT use. Relevant measures directed against the modifiable risks may provide a positive impact on public health and quality of life of Japanese. © 2011 by the American Academy of Ophthalmology.

Background and objective. Unilateral spatial neglect (USN) can interfere with rehabilitation processes and lead to poor functional outcome. The purpose of this study was to determine whether prism adaptation (PA) therapy improves USN and functional outcomes in stroke patients in the subacute stage. Methods. A multicenter, double-masked, randomized, controlled trial was conducted to evaluate the effects of a 2-week PA therapy on USN assessed with the Behavioral Inattention Test (BIT), the Catherine Bergego Scale (CBS), and activities of daily living (ADL) as evaluated with the Functional Independence Measure (FIM). A total of 38 USN patients with right-brain damage were divided into prism (n = 20) and control (n = 18) groups. Patients were divided into mild and severe USN groups according to BIT behavioral test (mild 55 and severe<55). The prism group performed repetitive pointing with prism glasses that induce rightward optical shift twice daily, 5 days per week, for 2 weeks, whereas the control group performed similar pointing training with neutral glasses. Results. The FIM improved significantly more in the prism group. In mild USN patients, there was significantly greater improvement of BIT and FIM in the prism group. Conclusions. PA therapy can significantly improve ADL in patients with subacute stroke. © 2011 American Society of Neurorehabilitation.

Aims/Introduction: To examine the cross-sectional relationship between sleep duration and impaired glucose tolerance (IGT), including diabetes mellitus (DM), we analyzed a large-scale healthy workers database in Japan. Materials and Methods: We examined the baseline database of 4143 participants (3415 men and 728 women) aged 19-69years. Sleep duration of participants was categorized into four groups: <6, 6 to <7, 7 to <8 and ≥8h. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). We defined IGT including DM (IGT/DM) in the present study according to previous studies as follows: fasting blood sugar level ≥110mg/dL, or if <8h after meals ≥140mg/dL, or on medication for diabetes mellitus, or those diagnosed as having DM. Logistic regression was applied to estimate the odds ratio (OR) to examine the relationship between IGT/DM, sleep duration and other related factors. Results: The number of participants with IGT/DM was 402 (9.7%). The factors that significantly associated with IGT/DM were age (OR 1.08, 95% confidence interval [CI] 1.07-1.10, P<0.001), high blood pressure (OR 1.94, CI 1.52-2.47, P<0.001), and <6h of sleep duration in comparison with 6 to <7h sleep (OR 2.32, CI 1.18-4.55, P=0.015). The associations of difficulty in sleep initiation, IPAQ classification, current smoking and alcohol intake with IGT/DM were not statistically significant. Conclusions: Our results showed that shorter sleep duration (<6h of sleep duration per night) was associated with a risk of IGT/DM independent of other lifestyle habits and metabolic risk factors. © 2011 Asian Association for the Study of Diabetes and Blackwell Publishing Asia Pty Ltd.

Studies have associated hearing impairment with adverse health outcomes, but the actual impact of hearing difficulty has been barely investigated. We investigated among older adults (i) the prevalence of hearing difficulty, (ii) the association of hearing difficulty with a composite outcome of dependence in activities of daily living (ADL) and death, and (iii) the population attributable risk fraction (PAF) of hearing difficulty. In 2005, a home-visit survey of 1364 Japanese older adults aged ≥65 (participation proportion = 95.5%) was conducted to evaluate self-reports of hearing difficulty. Over 3 years, 99.4% of the initial sample was followed. Outcomes were measured by incidence of death or dependence in ADL. In the sample, the prevalence of hearing difficulty was 17.7% (age ≥65) and 25.7% (age ≥75). Hearing difficulty at high levels was associated with a composite outcome of dependence in ADL and mortality (adjusted odds ratio = OR and 95% confidence interval = 95% CI = 6.19 (1.92-19.92)) as well as with each outcome independently. Improving the hearing difficulty from high to moderate or no difficulty would reduce the composite outcome in 4.3% (age ≥65) and in 6.3% (age ≥75) of the target population. In conclusion, hearing difficulty was common, was associated with and had substantial impact on adverse health outcomes. © 2010 Elsevier Ireland Ltd.