Table 1. Demographics and lung function (baseline and change from time of initial diagnosis with Western red cedar asthma).

	N	Mean	SD	Range
Age (years)	40	62.0	10.0	33, 82
Years from initial diagnosis	40	24.5	6.8	6, 38
Years from last exposure	40	17.0	9.3	1, 34
FEV1, percent predicted	40	83.2	16.1	48, 128
PC20-FEV1 (methacholine, mg/ml)	40	6.8	6.8	0.1,16.0
Change of PC20 (mg/ml)	30*	2.0	8.7	−24.1,15.0
Change of FEV1 (L)	40	−1.5	0.6	−2.6, −0.4
Change of FEV1 per year (L)	40	−0.07	0.05	−0.3, −0.01

^*10 subjects did not have PC₂₀ available from the time of initial diagnosis with Western red cedar asthma