経年栄養調査対象者の参加・脱落

Abstract

Food consumption surveys of the female population were conducted every year in a semi-rural community for eight years. The authors examined their commitment to the surveys. The surveys have been executed on women's food consumption by weight record method every year since 1978 in Ohami-Shirasatocho, chiba prefecture. The results were as follows : 1) The population size was 108 in the first year, and it increased gradually to 196 persons in 1980. The number of the participants of the survey was between 80 and 106. The participation rate of the population was 74.1% in 1978 and 82.5% in 1979. It decreased gradually to 49.0% in 1985. 2) The participation rate showed decreasing tendency during the observed pariod with some fluctuation. Half of the participants in the first year remained in the survey in the last observed year. 3) Up to the fourth year, the rate of those who dropped out was over 60%. But, it became fewer after that year. About 24% of the original participants in the first year still remained as active participants in 1985, even after eight years. 4) The frequency of participation shows ; while the participants in 1978 were surveyed 7 or 8 times, those who began to participate in subsequent years were less active in the survey. 5) It is desirable to consider these factors at the planning stages of the field survey in order to maintain a certain number of participants.