Teruichi Shimomitsu

Association between perceived neighborhood environment and walking among adults in 4 cities in Japan

Background Recent research highlights the importance of environment as a determinant of physical activity; however, evidence among Japanese is sparse. The aim of this study was to examine the association between perceived neighborhood environment and neighborhood walking for multiple purposes among Japanese. Methods We conducted a population-based, cross-sectional study of 1461 Japanese adults (age: 48.2 ± 14.1 years, men: 44.8%). Neighborhood environment and walking were assessed by a validated questionnaire. The odds ratio of active walkers was calculated in relation to environmental characteristics after adjustment for age, sex, and other potential confounders. Results Participants were more likely to walk when they perceived that there was high residential density (odds ratio, 1.47; 95% confidence interval, 1.11–1.96), fair land use mix–diversity (1.37, 1.04–1.81), good walking/cycling facilities (1.56, 1.19–2.04), and attractive aesthetics (1.49, 1.14–1.95). Environmental factors associated with walking differed with respect to the purpose for walking. The environmental characteristics associated with walking for daily errands and with walking for commuting were similar, and included residential density and land use mix. Walking for leisure was associated with walking/cycling facilities, aesthetics, and traffic safety. Stratified analyses showed some sex-specific associations. Among women, there was an unexpected inverse association of leisure walking with both residential density and land use mix–diversity. Conclusions The association between neighborhood environment and walking differed by walking purpose. The results were generally consistent with those of studies conducted in Western countries, except for the association of high residential density and good land use mix–diversity with less leisure walking in women. These results suggest possible targets for environmental interventions to promote walking.

Association of physical activity and neighborhood environment among Japanese adults.

OBJECTIVE Although environmental attributes related to physical activity is an emerging research topic, most studies have been reported from Western countries. This study aimed to examine the relationship between perceived environment and physical activity among Japanese adults. METHODS The sample included 492 adults aged 20 to 74 years (61%: male) living in Tokyo and Himeji in Japan. Primary measures were the short version of International Physical Activity Questionnaire and its Environmental Module. Data were collected between October and December 2003. Odds ratio (OR) of meeting physical activity recommendations was examined in relation to neighborhood environmental characteristics, adjusted for age, sex, employment status and education. RESULTS Three perceived environmental attributes were significantly related to walking 150 min/week or more: high residential density (OR=1.82), good access to shops (OR=1.65) and presence of sidewalks (OR=1.65). Two environmental attributes, access to shops (OR=2.32) and the presence of bike lanes (OR=1.57), were related to high levels of moderate to vigorous physical activity (950 MET*min/week or more). CONCLUSION Associations of physical activity with four environmental attributes emerged in this Japanese sample. These results support the generalizability of findings on physical activity environments across Western countries and Japan.

Television viewing time is associated with overweight/obesity among older adults, independent of meeting physical activity and health guidelines

Background Previous studies have shown associations of sedentary behavior with cardiovascular risk, independent of moderate-to-vigorous physical activity (MVPA). However, few studies have focused on older adults. This study examined the joint associations of television (TV) viewing time and MVPA with overweight/obesity among Japanese older adults. Methods A population-based, cross-sectional mail survey was used to collect self-reported height, weight, time spent in TV viewing, and MVPA from 1806 older adults (age: 65–74 years, men: 51.1%). Participants were classified into 4 categories according to TV viewing time (dichotomized into high and low around the median) and MVPA level (dichotomized into sufficient and insufficient by the physical activity guideline level of ≥150 minutes/week). Odds ratios (ORs) for overweight/obesity (body mass index ≥25 kg/m2) were calculated according to the 4 TV/MVPA categories, adjusting for potential confounders. Results Of all participants, 20.1% were overweight/obese. The median TV viewing time (25th, 75th percentile) was 840 (420, 1400) minutes/week. As compared with the reference category (high TV/insufficient MVPA), the adjusted ORs (95% CI) of overweight/obesity were 0.93 (0.65, 1.34) for high TV/sufficient MVPA, 0.58 (0.37, 0.90) for low TV/insufficient MVPA, and 0.67 (0.47, 0.97) for low TV/sufficient MVPA. Conclusions In this sample of older adults, spending less time watching TV, a predominant sedentary behavior, was associated with lower risk of being overweight or obese, independent of meeting physical activity guidelines. Further studies using prospective and/or intervention designs are warranted to confirm the presently observed effects of sedentary behavior, independent of physical activity, on the health of older adults.

Perceived neighborhood environment and walking for specific purposes among elderly Japanese.

Background Recent research has revealed the importance of neighborhood environment as a determinant of physical activity. However, evidence among elderly adults is limited. This study examined the association between perceived neighborhood environment and walking for specific purposes among Japanese elderly adults. Methods This population-based, cross-sectional study enrolled 1921 participants (age: 65–74 years, men: 51.9%). Neighborhood environment (International Physical Activity Questionnaire Environmental Module) and walking for specific purposes (ie, transportation or recreation) were assessed by self-report. Multilevel logistic regression analyses with individuals at level 1 and neighborhoods at level 2 were conducted to examine the association between environment and walking, after adjustment for potential confounders. Results Access to exercise facilities, social environment, and aesthetics were associated with total neighborhood walking. Odds ratios (95% CI) were 1.23 (1.00–1.51), 1.39 (1.14–1.71), and 1.48 (1.21–1.81), respectively. Regarding walking for specific purposes, social environment and aesthetics were consistent correlates of both transportation walking and recreational walking. Environmental correlates differed by specific types of walking and by sex. Transportation walking significantly correlated with a greater variety of environmental attributes. Sex differences were observed, especially for transportation walking. Bicycle lanes, crime safety, traffic safety, aesthetics, and household motor vehicles were significant correlates among men, while access to shops, access to exercise facilities, and social environment were important among women. Conclusions Specific environment–walking associations differed by walking purpose and sex among elderly adults. Social environment and aesthetics were consistent correlates of both transportation walking and recreational walking. Improving these environmental features might be effective in promoting physical activity among elderly Japanese.

Quantification of ischemic muscle deoxygenation by near infrared time-resolved spectroscopy

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

Time Trends for Step-Determined Physical Activity among Japanese Adults

PURPOSE The studys purpose was to describe the most recently reported (2007) step-determined physical activity and trends from 1995 to 2007 among Japanese adults. METHODS Data were extracted from published reports of the Japan Heath and Nutrition Survey, which has been conducted annually by the Ministry of Health, Labour and Welfare of Japan using a nationally representative Japanese adult sample of 6502-9833 participants (≥20 yr) each year. Pedometer data were collected on an individually specified weekday in November each year. Because of the change in age distribution of the sample, steps per day were adjusted by age to examine time trends. RESULTS Men took 7321 ± 4588 (mean ± SD) steps per day and women took 6267 ± 3827 steps per day in the Japan Heath and Nutrition Survey 2007. Men took more steps per day than women in all age groups. Steps per day were lower with older age groups among men, whereas among women, the 40- to 49-yr-old age group took the highest steps per day relative to other ages. Time trends displayed a decline of age-adjusted mean steps per day (-529 steps per day among men and -857 steps per day among women) from peak values in 1998-2000 to 2007. Decreases in percent of people classified as active (age-adjusted proportion taking ≥10,000 steps per day = -5.1% among men and -5.0% among women) and increases in percent classified as sedentary (age-adjusted proportion taking <4000 steps per day = +4.8% among men and +8.2% among women) were also observed during the same period. CONCLUSIONS Japanese steps per day have decreased over time from a peak around 1998-2000. The increase in the percent taking <4000 steps per day was especially noticeable among women.

Vitamin E supplementation and endurance exercise: are there benefits?

It has been widely noted that vitamin E shows numerous beneficial effects through and beyond its antioxidative properties; consequently, vitamin E is expected to prevent degenerative diseases. In the field of sports medicine, many studies dealing with vitamin E have been conducted originally from the point of view of its effects on physical performance. Although some earlier studies indicated that vitamin E supplementation could improve physical performance, defects in the study design or statistical analysis were pointed out at a later time. The majority of subsequent well controlled studies have reported no significant effect on physical performance from vitamin E supplementation. Recent studies suggest that endurance exercise may promote free radical generation in the body, and vitamin E may play an important role in preventing the free radical damage associated with endurance exercise. Although there is evidence of free radical involvement in exercise-induced muscle injury, vitamin E supplementation might not be expected to prevent muscle damage caused by exercise in humans without a vitamin E deficiency. Since it is still unclear whether exercise induces lipid peroxidation in the human body, the beneficial effect of vitamin E supplementation on exercise-induced lipid peroxidation has not yet been established. However, it is proposed that as a result of exercise vitamin E may be mobilised from store tissues and redistributed in the body to prevent oxidative damage. Therefore, we are convinced that vitamin E contributes to preventing exercise-induced lipid peroxidation. It has also been indicated that strenuous endurance exercise may enhance the production of oxidised low density lipoprotein (LDL), which plays a key role in the initiation and progression of atherosclerosis. It is also suggested that this enhanced production of oxidised LDL could be reduced if a higher vitamin E status is maintained. Supplementation with 100 to 200mg of vitamin E daily can be recommended for all endurance athletes to prevent exercise-induced oxidative damage and to reap the full health benefits of exercise.

Factors Associated With Shift Work Disorder in Nurses Working With Rapid-Rotation Schedules in Japan: The Nurses’ Sleep Health Project

Workers who meet the criteria for shift work disorder (SWD) have elevated levels of risk for various health and behavioral problems. However, the impact of having SWD on shiftworkers engaged in rapid-rotation schedules is unknown. Moreover, the risk factors for the occurrence of SWD remain unclear. To clarify these issues, we conducted a questionnaire-based, cross-sectional survey on a sample of shiftworking nurses. Responses were obtained from 1202 nurses working at university hospitals in Tokyo, Japan, including 727 two-shift workers and 315 three-shift workers. The questionnaire included items relevant to age, gender, family structure, work environment, health-related quality of life (QOL), diurnal type, depressive symptoms, and SWD. Participants who reported insomnia and/or excessive sleepiness for at least 1 mo that was subjectively relevant to their shiftwork schedules were categorized as having SWD. The prevalence of SWD in the sampled shiftworking nurses was 24.4%; shiftworking nurses with SWD showed lower health-related QOL and more severe depressive symptoms, with greater rates of both actual accidents/errors and near misses, than those without SWD. The results of logistic regression analyses showed that more time spent working at night, frequent missing of nap opportunities during night work, and having an eveningness-oriented chronotype were significantly associated with SWD. The present study indicated that SWD might be associated with reduced health-related QOL and decreased work performance in shiftworking nurses on rapid-rotation schedules. The results also suggested that missing napping opportunities during night work, long nighttime working hours, and the delay of circadian rhythms are associated with the occurrence of SWD among shiftworking nurses on rapid-rotation schedules. (Author correspondence: yuinoue@tokyo-med.ac.jp)

The Effort-reward Imbalance Model : Experience in Japanese Working Population

The Effort‐reward Imbalance Model: Experience in Japanese Working Population: Akizumi Tsutsumi, et al. Okayama University Graduate School of Medicine and Dentistry—The validity of Siegrists effort‐reward imbalance model was examined in Japanese workers: 105 dental technicians, 902 employees of production companies, and 2,827 selected from staff of hospitals. After controlling for possible confounders, levels of the two stress measures, ‘effort‐reward imbalance’ and ‘overcommitment’, were similar for both genders. The effort‐reward imbalance was most prevalent in the 25‐ 30 age employees and then decreased with age, but the level of overcommitment increased with age. Those with lower educational attainment and others who reported working long hours were more often exposed to effort‐reward imbalance and those in the private sector reported higher overcommitment levels than their respective counterparts. Hospital staff (predominantly nurses) had almost twice as high a level of effort‐reward imbalance as production workers. A review of empirical studies confirmed validity of the criterion with respect to a self‐reported health outcome and the responsiveness of the measures to organizational changes. Nevertheless, the low prevalence of an effort‐reward imbalance (originally formulated by Siegrists group on European samples) in Japanese employees seemed to reduce the statistical power of these tests. A subsequent change in exposure prevalence by defining the top quintile of the distribution of the logarithmic‐transformed effort‐ reward ratio resulted in an improvement in the statistical fit. The Japanese evidence indicates promising applicability of the effort‐reward imbalance model, particularly if statistical approaches that measure the models core notion are extended, and recommendation of repeated measures for exposure. Cross‐cultural research on occupational stress is instructive in terms of health science.

Differences in HDL Cholesterol Concentrations in Japanese, American, and Australian Children

BACKGROUND Mortality from coronary heart disease is relatively low in Japan compared with other developed countries and has remained low despite an increasing standard of living and an apparent increase in mean plasma cholesterol concentration in adults over the past three decades. Important differences in childhood plasma lipoprotein profile might contribute to some of the difference in coronary heart disease mortality seen between Japan and both Australia and North America. METHODS AND RESULTS Plasma HDL cholesterol and total cholesterol were surveyed in representative populations of schoolchildren in Australia, Japan, and Bogalusa, La. The mean concentration of plasma HDL cholesterol (but not total cholesterol) was higher for Japanese schoolchildren than for Australian or US schoolchildren (P<.001). In addition, the difference in plasma HDL cholesterol between the ages of 8 to 10 years and 12 to 15 years was much greater for Australian (boys, 15.2%; girls, 2.6%) and US (boys, 9.1%; girls, 2.7%) children than for their Japanese counterparts (boys, 4.2%; girls, 1.9%). An examination of potential explanatory factors revealed little difference in body mass index between samples, higher physical activity levels for the Japanese compared with the Australians, and substantial differences in dietary intake between Japanese and Australian schoolchildren. CONCLUSIONS The relatively high ratio of plasma HDL cholesterol to total cholesterol in Japanese schoolchildren and the relatively small negative difference of plasma HDL cholesterol with age may help to explain why the coronary heart disease mortality rate in Japan is low compared with that in other developed countries.