Figure 2

The number and frequency of cases demonstrating the blue and red pattern in each age group. The black bar indicates the number of positive cases; white bar indicates negative cases. The positive ratios of blue and red pattern in each group are described at the left and right side of each bar, respectively. The blue pattern was increasingly frequent with age (* P < 0.01, Cochran-Armitage test and logistic regression model), while the red pattern was unrelated to age.