Table 4.

Factor loadings (varimax rotation) across study windows

	Lung Function		BD Response/Ratio		Inflammatory/Atopic		Symptoms		Exacerbation
	screening	48 month	screening	48 month	screening	48 month	screening	48 month	screening	48 month
Pre-BD FEV1	√	√
Pre-BD FVC	√	√
Pre-BD Peak Flow	√	√
Pre-BD FEV1/FVC ratio			√	√
FEV1 BD Responsiveness			√	√
Total serum IgE level (ng/ml)*					√	√
No. of positive core skin tests					√	√
Total Eosinophil Count (mm3)*					√	√
FEV1 PC20 methacholine, mg/ml*					√	√
Mean Symptom Score							√	√
No. of days with albuterol puffs							√	√
No. of episode-free days							√	√
No. of doctor contacts									√	√
No. of school absences									√	√
No. of nights awakened								√	√
No. of days w/prednisone use**	n/a		n/a		n/a		n/a		n/a	√
% of variance explained	17.10%	16.40%	10.10%	9.20%	9.30%	9.20%	8.90%	11.60%	5.80%	12.00%

^*Data was logarithimically transformed for this analysis

^**Participants were taken off of Prednisone during the 28 day screening period but could use it afterwards