a decreasing trendp < 0.001
7 The incidence of ICC among Japanese women aged 20–29 years significantly increased during 1975–2011 (APC 5.9, 95% confidence interval [95%CI] 5.6 to 6.1, p < 0.001), in line with previous reports, 13 , 14 , 15 but converted to a decreasing trend from 8.0 to 2.8 (reduction rate 65.0%) during 2011–2020 (APC −13.5, 95%CI −11.9 to −14.5, p < 0.001).