Table 1. The prevalence of 12bp insertion by DNA Sequencing.

Okinawa, Japan	Total	Positive
East-Asian-type cagA/vacA s1m1	9	0	(0.0%)
East-Asian-type cagA/vacA s1m2	15	2	(13.3%)
Western-type cagA/vacA s1m1	10	5	(50.0%)
Western-type cagA/vacA s1m2	31	26	(83.9%)
United State	Total	Positive
East-Asian-type cagA/vacA s1m2	4	0	(0.0%)
Western-type cagA/vacA s1m1	12	0	(0.0%)
Western-type cagA/vacA s1m2	16	6	(37.5%)
Western-type cagA/vacA s2m2	1	0	(0.0%)

^*cagA type was determined based on the 3′ region of cagA sequence