子供の生活環境と健康に関する研究 (第２報)

In this second report, we aimed to argue the lifestyle habits and stress level of preschoolers as indexes of s-IgA (secretory Immunoglobulin A) and -amylase in saliva. Subjects were 38 kindergarteners and their guardians of W kindergarten in K city of Kanagawa Prefecture. Basic lifestyle habits of the kindergarteners were analyzed and compared with the same items as the previous report “Studies on Preschoolers’ Physical Activities and Lifestyle” 12) . Collection of saliva was performed six times for two days in the kindergarten (upon arrival at the kindergarten, before lunch, and just before going home) and three times at home by guardians (before dinner, at bedtime, and when waking up in the morning). The average wake-up time was significantly earlier in the Y nursery school and the W kindergarten than the K nursery school (p0.001). The average bedtime was significantly earlier in the Y nursery school and the W kindergarten than the K nursery school (p0.01). The average sleeping period was significantly longer in the Y nursery school and the W kindergarten than the K nursery school (p0.001). From this study, there are many ratios of preschoolers showing lifestyle habits such as short sleeping period, late wake-up time, and late bedtime in the nursery school located in the city. Conversely, many ratios of preschoolers showed lifestyle habits such as longer sleeping period, early wake-up time and, early bedtime in the preschool and kindergarten located in the mountain area and the quiet residential area. However, the playing locations did not show significant difference by areas. One possible reason for this may be that the playing space of preschoolers is governed by the social backgrounds including TV games rather than environmental factors. A correlation was not recognized between the average values s-IgA / total protein and the activities of -amylase in saliva from arrival at the nursery school or kindergarten on the first day to just before going home the next day. However, a reverse correlation of the average values of s-IgA / total protein and the average activities of -amylase on wake-up, was observed with high tendency of the former and lower tendency of the latter. Therefore, the preschoolers investigated in this study are believed to have proper stress levels by maintaining sufficient sleep and living a proper lifestyle.