Health practices in puberty are formed during infancy. There are few reports on bone mass acquisition during infancy, and there is little consensus on the relationship between Osteo Sono-assessment Index (OSI) and other factors. In this study, we measured the height, weight, body fat percentage, foot size, and OSI of kindergarten-age children and administered a questionnaire survey. We studied 280 children (165 boys ; 115 girls) for whom consecutive data for 2 years were available. Factors that affect bone mass acquisition such as diet, exercise, and sleep were analyzed using multinomial logistic regression analysis, after adjusting for growth factors. Factors that increased the OSI in boys included “sport lessons”, “under 10 hours of sleep”, and “going to bed before 10 pm”. Factors that increased the OSI in girls included “exercise”, “under 10 hours of sleep”, and “going to bed before 10 pm”. The average sleep duration was 9 hours 20 minutes. Based on these findings, we recommend that sports and exercise become an important part of the health education of boys and girls, respectively. Further, a sleep duration of under 10 hours and a bedtime earlier than 10 pm should be encouraged in both boys and girls.
The purpose of this study was to investigate the work-related stress among Japanese emergency doctors who worked harder than other Japanese doctors, in 2003. The analysis of 62 emergency doctors from 5 tertiary emergency medical centers shows that their stress consisted of “irregular life-style and scarce private hours”, “health-related anxiety owing to strong physical burden”, “cheap rewards and few night-duty allowances”, “few nap and meal breaks during duty,” etc. Further, results show that work-related stress differ among job-class (managers, staff doctors, and residents) ; for example, managers' distinctive stress was “the trouble from the patients' insistence of being examined by experts”, and those of residents was “poor cooperation with other clinical departments”. It is important to manage the stress levels and improve emergency doctors' health and ensure their job satisfaction. In Japan, reports about the overwork of Japanese emergency doctors were published after 2005. This has seemed to be changing the work conditions of doctors. However, there are only few investigations to indicate this improvement. Further studies are needed to investigate emergency doctors' work-related stress after 2005.