Figure 2.

Adjusted relative risk ratios for severe airway hyperresponsiveness (AHR). From multinomial logistic regression models by serum CC16 (club cell secretory protein 16) tertile categories from age 11 to age 26 years (n subjects = 555; n observations = 1,228). High CC16 is the reference category. Error bars indicate 95% confidence intervals. Estimates for mild and moderate AHR are not presented in the figure, but they are reported in Table 3. No AHR is the reference group for both estimates presented in the figure and in Table 3. RRR = relative risk ratio.