Seventy hundred and sixty one patients of cholelithiasis, who had been operated at twenty two hospitals in Aomori prefecture from 1964 to 1969, were investigated into the distribution of area, age, sex, occupation and so on.
1) Gallstones were classified into cholesterin stones, and pigmented calcium stones. Generally speaking, cholesterin stones and pigmented calcium stones were found in equal ratio in Aomori prefecture. In western part of the prefecture faced the Japan Sea, pigmented calcium stones got an advantage over cholesterin stones, but in some cities of the eastern part of the prefecture, cholesterin stones were predominant. In other districts, both stones were found in nearly equal ratio.
2) On the basis of vital statistics classified in age, 60 to 69 years old were the most frequent age to have gallstones. Pigmented calcium stones were less common than cholesterin stones among patients of age between 10 to 49 years old. Among older patients, pigmented calcium stones were almost equally frequent as cholesterin stones.
3) Women had much tendencies to have gallstones especially cholesterin stones. Pigmented calcium stones were equally distributed in men and women.
4) Divided the patients with cholelithiasis into professional and laboring groups, the laboring group existed in between 30 to 80 per cent of the patients, which were nearly equal to the ratio of inhabitants in these area. We should confirm that one of the reason why cholestrin stones were increasing at some cities in the prefecture recently might be the result of the increase of the number of professional group. Whereas, decreasing of pigmented calcium stones in other area might be the result of the decrease of the number of laboring group in the area.
