dyspnea (OR = 2.0; 95% CI, 1.7–2.4), and persistent wheezing (OR = 1.8; 95% CI, 1.5–2.3) were all more likely among arrival group 1 members. A similar pattern was appar- ent for those with persistent URS: persistent rhinosinusitis (OR = 1.3; 95% CI, 1.1–1.6) and persistent sore throat (OR = 1.6; 95% CI, 1.3–1.9). In contrast, asymptomatic status was consistently related to later arrival status (p < 0.0001; Table 2). The prevalence of smoking in the cohort was 13.5%, 11.1%, and 75.4% for current, former, and never smokers, respectively. Current and former smokers were generally Trends in post-9/11 respiratory symptoms overrepresented among those with persistent symptoms. We also carried out analyses com- paring persons with persistent symptoms with those who recovered. We found that current smoking compared with never smoking was associated with persistent wheeze (OR = 1.5; 95 CI, 1.1–2.1), cough (OR = 1.5; 95% CI, 1.1–2.0), and GERD (OR = 1.6; 95% CI, 1.2–2.3). Former smoking compared with never smoking was not significantly asso- ciated with individual symptoms but was associated with persistent LRS (OR = 1.3; 95% CI, 1.0–1.8) and URS (OR = 1.3; 95% CI, 1.0–1.7). Table 1. Annual prevalence of symptoms in 10,378 firefighters by arrival group (%).a Yearb Arrival group 1 2 (n = 8,920) (n = 1,197) 3 (n = 2,889) 4 (n = 4,441) Percent change, years 1–4c 64.3 54.8 48.4 37.4 54.4 39.2 32.5 25.0 44.2 33.7 29.7 21.5 50.6 45.5 42.4 35.5 70.4 63.2 58.5 45.9 53.7 41.5 35.6 28.3 25.9 16.1 13.7 8.4 57.7 42.3 31.3 20.0 51.2 36.5 31.3 22.1 50.2 41.8 37.4 24.2 48.8 35.5 32.1 18.9 51.2 39.4 39.7 30.5 24.3 16.9 12.6 10.7 54.3 43.2 34.9 26.6 48.4 38.7 32.7 23.7 53.9 48.4 40.9 31.6 48.9 39.2 28.6 26.6 53.6 45.9 35.5 27.7 20.0 16.1 12.7 6.0 50.1 39.6 28.7 19.2 43.5 35.5 23.2 17.9 54.4 49.1 39.6 32.5 45.6 38.2 26.3 21.5 53.9 43.2 35.0 28.5 –68.9 –70.6 –73.8 –84.0 –7.9 1.0 –11.9 –23.2 –1.5 5.6 –21.9 –16.7 7.4 7.9 –6.6 –8.5 –35.1 –39.6 –55.1 –53.1 0.4 4.1 –1.7 0.7 p-Valued < 0.0001 < 0.0001 < 0.0001 < 0.0001 0.554 0.002 0.273 0.269 0.090 < 0.0001 0.034 0.514 0.193 < 0.0001 0.416 0.079 < 0.0001 < 0.0001 < 0.0001 < 0.0001 0.645 < 0.0001 0.847 0.781 Year 1 Year 4 year 1 and remained between 40% and 45% during all 4 post-9/11 years (Figure 1). Prevalence by arrival group in cross- sectional analyses. For all symptoms, earlier arrival was associated with higher prevalence in all years (all p < 0.01). For cough, dysp- nea, wheeze, sore throat, and rhinosinusitis, those in arrival groups 3 and 4 experienced a greater proportion of decline over time com- pared with changes in earlier arrival groups (Table 1, Figure 2). Symptom progression in the cohort. A total of 3,722 firefighters completed both year 1 and year 4 questionnaires. In year 1, the mean (± SD) number of reported symptoms per person was 2.6 ± 2.0, which significantly declined to 2.2 ± 2.0 (p < 0.0001) in year 4. On the initial questionnaire, 64.1% reported one or more LRS, 69.7% one or two URS, and 38.4% GERD. At year 4, the prevalence of any LRS declined significantly to 49.5%, largely attributable to the 69.0% decline in cough, because both dyspnea and wheeze significantly increased from 35.2% to 39.4% and from 28.9% to 34.6%, respectively (p < 0.001 for both). Similarly, we found a significant decline (p < 0.001) in any URS to 57.3%, primarily attributable to a 37.4% decline in sore throat, because rhinosinusitis significantly increased from 44.1% to 48.7% (p < 0.001). The prevalence of GERD also increased from 38.4% to 43.8% (p < 0.001). Factors associated with symptom patterns in the cohort. We explored the relationship between arrival group and symptom patterns in the cohort with year 1 and year 4 ques- tionnaires (n = 3,722). Earlier arrival group was consistently related to symptom persis- tence for LRS, URS, and GERD. Comparing earliest arriving participants (arrival group 1) with all others, arrival group 1 members were more likely to have LRS (OR = 1.8; 95% CI, 1.5–2.2), URS (OR = 1.5; 95% CI, 1.3–1.8), and/or GERD (OR = 1.9; 95% CI, 1.5–2.2) at year 4. This held true for each individual symptom as well. For LRS, persistent cough (OR = 1.7; 95% CI, 1.3–2.1), persistent Cough Dyspnea Wheeze Rhinosinusitis Sore throat GERD 80 70 s 60 m o t pm50 y s ith40 w tn30 e c re20 P 10 0 Symptom Cough Dyspnea Wheeze Rhinosinusitis Sore throat GERD 80 70 60 s m tpo 50 m y s tih 40 w t en 30 c r e P 20 10 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 ap-Values all < 0.01, by McNemar’s test for trend between symptom prevalence and arrival group. bIndividuals in each year may not be the same. cCalculated as (year 4 – year 1)/(year 1) × 100. dp-Values from marginal logistic regression model fitted with generalized estimating equations, with an exchangeable within-individual correlation. Year 1 Year 2 Year 3 Year 4 0 Arrival 1 2 3 group Cough 4 1 2 3 Dyspnea 4 1 2 3 Wheeze 4 1 2 3 Rhinosinusitis 4 1 2 3 Sore throat 4 1 2 3 GERD 4 Symptom Figure 1. Trends in the prevalence of symptoms in 10,378 firefighters from 2001 through 2005. Figure 2. Trends in the prevalence of symptoms in 10,378 firefighters during year 1 (2001–2002) and year 4 (2004–2005) by arrival group. Environmental Health Perspectives • volume 117 | number 6 | June 2009 977