A statistical analysis of the decrease in death rate from peptic ulcer during twenty-five years (1950-1975) after the Second World War in Japan

Abstract

The death rate from peptic ulcer decreased gradually during 25 years after the Second World War in Japan (Vital Statistics, Ministry of Health & Welfare). The difference in the death rate during the period was analysed every five years (5 year difference), between 46 prefectures (inter-prectural difference), by means of analysis of variance (two-way layout). The decrease in the death rate (5 year difference) was significant in all age groups of 15-74 year old males, and 15-79 year old females (p <0.05). The decrease was most significant for males aged 40-69 years. The inter-prefectural difference was most significant for males aged 40-69 years as well. The difference was greater for males than for females in the 15-64 year age groups. It was assumed that steady and extensive development of the screening system for gastric cancer and peptic ulcer for working people was the main factor leading to the age and sex characteristics of the decrease and inter-prefectural difference in the death rate.