Table 3.

Stepwise multiple logistic regression for the association between reporting any occupational cold exposure at baseline and incident wheeze, long-standing cough, or productive cough

Step	Any occupational cold exposure (NRS > 1) at baseline	Incident wheeze	Incident long-standing cough	Incident productive cough
		OR (95% CI)	OR (95% CI)	OR (95% CI)
I	Crude analysis	1.35 (1.08–1.69)*	1.08 (0.87–1.35)	1.32 (1.07–1.62)*
II	Physician-diagnosed asthma at baseline excluded (N = 591)	1.40 (1.10–1.79)*	1.03 (0.80–1.31)	1.32 (1.05–1.64)*
III	Physician-diagnosed chronic obstructive pulmonary disease at baseline excluded (N = 35)	1.42 (1.11–1.81)*	1.03 (0.80–1.31)	1.33 (1.06–1.66)*
IV	Non-workers at baseline excluded (N = 1064)	1.46 (1.11–1.93)*	0.99 (0.75–1.29)	1.34 (1.04–1.72)*
V	Adjusted for age at baseline (continuous)	1.47 (1.12–1.94)*	0.99 (0.75–1.29)	1.37 (1.06–1.75)*
VI	Adjusted for body mass index at baseline (continuous)	1.40 (1.06–1.85)*	0.96 (0.73–1.27)	1.36 (1.06–1.74)*
VII	Adjusted for daily smoking at baseline (yes/no)	1.38 (1.04–1.82)*	0.96 (0.73–1.26)	1.36 (1.05–1.74)*
VIII	Adjusted for occupational physical workload at baseline (high/low to medium)	1.41 (1.06–1.87)*	0.98 (0.74–1.29)	1.37 (1.06–1.77)*

OR odds ratio, NRS numerical rating scale, 95% CI ninety-five percent confidence interval

*Significant at the 0.05 level