Table 2.

Pre-exposure mean percent predicted pre-exposure FEV₁ and PEF for all participants and for Group 2 Participants over entire 7 years by study and by exposure status

Exposure Status	Date	All participants		Group 2 participants
		N	mean percent (%) predicted +/− Standard Deviation*	N	mean percent (%) predicted +/− Standard Deviation*
FEV1
Unexposed	Jan 2003	68	86.5+/−16.8	30	80.3+/−15.6
	May 2004	66	88.6+/−12.4	31	82.4+/−17.4
	Oct 20O4	71	85.5+/−17.2	31	82.2+/−17.6
	Jun 2006	62	86.2+/−17.0	32	84.3+/−16.7
	Sept 2007	62	83.2+/−20.6	27	83.9+/−15.7
	May 2008	73	79.8+/−20.2	30	79.7+/−16.3
Exposed	March 2003	58	84.9+/−17.0	26	79.5+/−16.5
	Feb 2003	79	84.5+/−18.2	33	84.8+/−16.3
	March 2003	79	84.3+/−19.2	35	84.7+/−16.7
	Sept 2006	47	80.9+/−18.7	34	82.6+/−16.3
	December 2009	55	84.3+/−18.5	23	82.5+/−16.9
PEF
Unexposed	Jan 2003	68	99.0+/−17.9	30	92.4+/−17.6
	May 2004	66	102.4+/−21.6	31	92.5+/−22.6
	Oct 20O4	71	97.1+/−21.1	31	94.3+/−20.2
	Jun 2006	62	97.2+/−19.6	32	91.5+/−17.8
	Sept 2007	62	94.9+/−23.7	27	94.8+/−17.3
	May 2008	73	91.5+/−23.2	30	89.9+/−19.4
Exposed	March 2003	58	97.4+/−20.1	26	91.4+/−19.3
	Feb 2003	79	98.1+/−22.3	33	97.3+/−18.4
	March 2003	79	98.1+/−22.9	35	96.8+/−19.1
	Sept 2006	47	92.9+/−19.9	34	94.7+/−17.1
	December 2009	55	96.6+/−22.2	23	94.3+/−21.5

^*Percent predicted FEV₁ standardized by age, gender, race, height, and weight (Hankinson et al. 1999); Group 2= participants in ≥4 exposure studies