BILATERAL TYPE DIVERTICULAR-DISEASE OF THE COLON

7,543 double-contrast barium enema studied for the presence of diverti cula which were classified into right-sided, left-sided and bilateral types, and the relationship of the frequency (detection rate) and numb ers of diverticula to age were examined for the earlier (1982-87) and later (1988-92) periods. Diverticular disease was found in 22.2% of ma le and 15.5% of female examinees. The right-sided type predominated am ong the subjects. Frequency distribution by age of the bilateral type was similar to that of the left-sided type. Bilateral diverticular dis ease increased in frequency with advancing years in the sixth and seve nth decade, the right-sided type increased in middle-aged subjects, an d the left-sided type did not. The bilateral type was composed of dive rticula in the right colon, where numbers were greater than in the pur e right-sided type, but remained unchanged with increasing age, and di verticula in the left colon, where numbers were similar to the pure le ft-sided type, but did not increase with age. Increase in the prevalen ce of bilateral and not pure left-sided form has contributed to the re cent increase in di; verticula in the left colon among the Japanese, a nd might have been preceded by an increase in the right-sided type.