Tatsuya Noda

Trends in Disability-Free Life Expectancy in Japan, 1995–2004

Background In Japan, life expectancy at birth is currently the highest in the world. However, recent trends in disability-free life expectancy in Japan have not been examined. Methods We used data from Japanese national surveys for the period 1995–2004. These surveys included information on activity status measured by common self-reported instruments. The numbers of expected years with and without activity limitation were estimated by using the Sullivan method. Results The numbers of expected years of life without activity limitation, at birth, in 1995 and 2004 were 68.5 and 69.7, respectively, in males and 72.1 and 73.0 in females. As a proportion of total life expectancy, at birth, these values represent a decrease from 89.7% to 88.6% in males and from 87.1% to 85.3% in females. The proportion of expected years with a limitation of some activities except activities of daily living (ADL) increased in males and females. The proportion of those with an ADL limitation increased in females, but not in males. Conclusions The trends in expected years with and without activity limitation suggest that the duration of life with a light or moderate disability increased in Japanese males and females during the period 1995–2004.

Population Size Estimation of Men Who Have Sex with Men through the Network Scale-Up Method in Japan

Background Men who have sex with men (MSM) are one of the groups most at risk for HIV infection in Japan. However, size estimates of MSM populations have not been conducted with sufficient frequency and rigor because of the difficulty, high cost and stigma associated with reaching such populations. This study examined an innovative and simple method for estimating the size of the MSM population in Japan. We combined an internet survey with the network scale-up method, a social network method for estimating the size of hard-to-reach populations, for the first time in Japan. Methods and Findings An internet survey was conducted among 1,500 internet users who registered with a nationwide internet-research agency. The survey participants were asked how many members of particular groups with known population sizes (firepersons, police officers, and military personnel) they knew as acquaintances. The participants were also asked to identify the number of their acquaintances whom they understood to be MSM. Using these survey results with the network scale-up method, the personal network size and MSM population size were estimated. The personal network size was estimated to be 363.5 regardless of the sex of the acquaintances and 174.0 for only male acquaintances. The estimated MSM prevalence among the total male population in Japan was 0.0402% without adjustment, and 2.87% after adjusting for the transmission error of MSM. Conclusions The estimated personal network size and MSM prevalence seen in this study were comparable to those from previous survey results based on the direct-estimation method. Estimating population sizes through combining an internet survey with the network scale-up method appeared to be an effective method from the perspectives of rapidity, simplicity, and low cost as compared with more-conventional methods.

Physical Activity and All-cause Mortality in Japan: The Jichi Medical School (JMS) Cohort Study

Background In April 2008, a new health check-up and health guidance system was introduced by the Japanese Government to promote increased physical activity. However, few studies have documented the health benefits of physical activity in Asian populations. We examined the association between all-cause mortality and level of physical activity in a Japanese multicommunity population-based study. Methods The Jichi Medical School Cohort Study is a multicommunity, population-based study based in 12 districts in Japan. Baseline data from 4222 men and 6609 women (mean age, 54.8 and 55.0 years, respectively) were collected between April 1992 and July 1995. The participants were followed for a mean duration of 11.9 years. To determine the association between all-cause mortality and level of physical activity, crude mortality rates per 1000 person-years and hazard ratios (HRs) with 95% confidence intervals (CI) were determined using the Cox proportional hazards model. Physical activity was categorized by using physical activity index (PAI) quartiles. The lowest (first) PAI quartile was defined as the HR reference. Results In men, the lowest mortality rate was observed in the third quartile, with 95 deaths and a crude mortality rate of 7.6; the age- and area-adjusted HR was 0.59 (95% CI, 0.45–0.76), and the mortality curve had a reverse J shape. In women, the lowest mortality rate was observed in the highest PAI quartile, with 69 deaths and a crude mortality rate of 3.5; the HR was 0.81 (95% CI, 0.58–1.12). Conclusion Our results suggest that increased physical activity lowers the risk for all-cause death in Japanese.

Gains in disability-free life expectancy from elimination of diseases and injuries in Japan.

Background Although disability-free life expectancy has been investigated in Japan, gains from elimination of diseases and injuries have not been examined. Methods We used data from the 2007 Japanese national health statistics to calculate the number of years with and without activity limitation that could be expected from eliminating 6 selected diseases and injuries. Results At birth, the number of expected years of life without and with activity limitation was 70.8 and 8.4, respectively, in males and 74.2 and 11.8 in females. More than 1.0 expected years without activity limitation were gained from eliminating malignant neoplasms and cerebrovascular diseases; smaller gains were observed after eliminating other diseases and injuries. Elimination of cerebrovascular diseases, dementia, and fracture decreased expected years with activities of daily living (ADL) limitation, and elimination of shoulder lesions/low back pain decreased expected years with non-ADL limitation. Conclusions Elimination of diseases and injuries increased expected years with and without activity limitation among Japanese, which suggests that improved prevention of those diseases and injuries—including cerebrovascular diseases and dementia—would result in longer disability-free life expectancy and fewer years of severe disability.

Incidence of Symptoms and Accidents During Baths and Showers Among the Japanese General Public

Background Bathing is a deeply ingrained custom among Japanese; however, data on the incidence rate of symptoms and accidents during bathing have not yet been reported for the Japanese general public. Methods We conducted a population-based cross-sectional study of 617 Japanese adults who attended a specialized health checkup. Participants completed a self-administered questionnaire to assess weekly frequencies of bathtub bathing and showering and the frequency of symptoms/accidents (falling, loss of consciousness, and other) during these activities in the past year. We calculated the incidence rates of accidents per 10 000 baths/showers and 95% confidence intervals (CIs) and compared the clinical characteristics of participants who had symptoms/accidents with those who did not. Results The incidence rates of accidents per 10 000 bathtub baths and showers were 0.43 (95% CI: 0.22–0.84) and 0.24 (95% CI: 0.04–1.37). Although these rates are low, there were 740 000 bathtub bathing-related accidents in Japan, due to the fact that bathing is an almost-daily habit. There was no significant difference in clinical characteristics between groups Conclusions We collected basic information on the incidence of bathing-related accidents in Japan. Falls and loss of consciousness during bathing or showering can potentially lead to a serious accident, so the general public should be educated about the possibility of such accidents during bathing.

Trends in life expectancy with care needs based on long-term care insurance data in Japan.

Background Using a previously developed method for calculating expected years of life with care needs based on data from the Japanese long-term care insurance system, we examined recent trends in expected years of life with care needs by age group and prefecture. Methods Information on care needs was available from the long-term care insurance system of Japan. Expected years of life with care needs by age group and prefecture in 2005–2009 were calculated. Results Expected years of life with care needs at age 65 increased from 1.43 years in 2005 to 1.62 years in 2009 for men, and from 2.99 to 3.44 years for women. As a proportion of total life expectancy, these values show an increase from 7.9% to 8.6% in men and from 12.9% to 14.4% in women. Expected years with care needs did not increase in the age groups of 65 to 69 and 70 to 74 years but markedly increased in the age group of 85 years or older. Expected years with care needs increased in every prefecture during the period studied. The difference in 2005 between the 25th and 75th percentiles in prefectural distributions was 0.16 years for men and 0.35 years for women. The difference remained nearly constant between 2005 and 2009. Conclusions Expected number of years of life with care needs increased among Japanese from 2005 to 2009, and there was a wide range in distribution among prefectures. Further studies on coverage of care needs under the long-term insurance program are necessary.

Brief Intervention in the Workplace for Heavy Drinkers: A Randomized Clinical Trial in Japan

AIMS To investigate the effectiveness of brief intervention (BI) conducted in the workplace for heavy drinkers. METHODS A randomized controlled trial was conducted at six companies in Japan. Participants were heavy drinkers who met the inclusion criteria and were randomized into three groups: the BI group, BI with diary group and a control group. Outcomes (total drinks, binge drinking episodes and alcohol-free days) were evaluated at 3 and 12 months. RESULTS The 304 participants recruited were allocated to the three groups and 277 participated in all follow-up evaluations. Dropout rates in the respective groups were 7.0, 14.9 and 5.5%. Some improvements were observed in all the groups. In particular, alcohol-free days in the BI group were significantly increased by 93.0% at 12 months. Total drinks at 12 months were reduced by 41 g per week in the BI group compared with the control group, although the intergroup difference was not significant. CONCLUSION BI in the workplace is effective for increasing the number of alcohol-free days. However, the effectiveness on decreasing alcohol consumption was unclear, which could be explained by alcohol screening itself causing a reduction in drinking.

Occupational Factors and Problem Drinking among a Japanese Working Population

Problem drinking is a serious public health problem in the workplace. However, few Japanese epidemiological studies have investigated the occupational characteristics of problem drinking. The purpose of this study is to clarify the occupational risk factors for problem drinking among a Japanese working population. We used data from a random-sampling survey about mental health and suicide, conducted among Hamamatsu City residents aged 15 to 79 yr old during May and June in 2008. The relation between occupational factors and problem drinking was analyzed with multiple logistic regression models stratified by gender. CAGE questionnaire was used to assess problem drinking. With regard to employment types, problem drinkers were more prevalent among self-employed women. With regard to occupational types, clerical and service professions had more problem drinkers of either sex, while administrative/managerial and sales professions had more women with such problem. With regard to company size, male problem drinkers were more prevalent in smaller companies than in larger ones. These results indicate that the prevalence of problem drinkers in the workplace depends on where one works. It is necessary to consider these characteristics to provide effective measures to address problem drinking in the workplace.

Effects of charcoal kiln saunas (Jjimjilbang) on psychological states

This uncontrolled intervention study explored the effects of sauna bathing utilizing residual heat from charcoal kilns (charcoal kiln saunas) on psychological states. Forty-five volunteers (24 males and 21 females; mean age 51.9 years (S.D. 15.7) visiting a bamboo charcoal kiln in Japan participated in the study. They completed a shortened version of the Profile of Mood States (POMS) and State-Trait Anxiety Inventory (STAI) before and after charcoal kiln sauna bathing in order to determine mood and anxiety states. Six factors relating to mood were measured using the POMS: Tension-Anxiety, Depression-Dejection, Anger-Hostility, Vigor, Fatigue, and Confusion. The two anxiety concepts of state anxiety and trait anxiety were also measured. Changes in psychological states before and after sauna bathing were then determined. All mood scales and both manifest anxiety measures were improved after sauna bathing. Charcoal kiln sauna bathing appears to improve mood and decrease anxiety. It is a limitation of this study that this was a descriptive prospective and an uncontrolled intervention study. Further investigation of the improvement of trait anxiety is required.

Gargling for Oral Hygiene and the Development of Fever in Childhood: A Population Study in Japan

Background Fever is one of the most common symptoms among children and is usually caused by respiratory infections. Although Japanese health authorities have long recommended gargling to prevent respiratory infections, its effectiveness among children is not clear. Methods The children in this observational study were enrolled from 145 nursery schools in Fukuoka City, Japan. Children in the exposure group were instructed to gargle at least once a day. The endpoints of this study were incidence of fever during the daytime and incidence of sickness absence. Differences among gargling agents for each endpoint were also analyzed. Results A total of 19 595 children aged 2 to 6 years were observed for 20 days (391 900 person-days). In multivariate logistic regression, the overall odds ratio (OR) for fever onset in the gargling group was significantly lower (OR = 0.68). In age-stratified analysis, ORs were significantly lower at age 2 (OR = 0.67), 4 (OR = 0.46), and 5 (OR = 0.41) years. Regarding sickness absence, the overall OR was 0.92 (not significant) in the gargling group. In age-stratified analysis, ORs were significantly lower at age 4 (OR = 0.68), 5 (OR = 0.59), and 6 (OR = 0.63) years. In subgroup analysis, significantly lower ORs for fever onset were observed for children who gargled with green tea (OR = 0.32), functional water (OR = 0.46), or tap water (OR = 0.70). However, the ORs were not significant for sickness absence. Conclusions Gargling might be effective in preventing febrile diseases in children.