Figures
- FIGURE 1
Flow chart of the study population.
- FIGURE 2
Remission and relapse of adult-onset asthma, from recruitment between 1995 and 1999 until follow-up between 2012 and 2014.
- FIGURE 3
Remission of adult-onset asthma at follow-up between 2012 and 2014 in relation to forced expiratory volume in 1 s (FEV1) % predicted and severe bronchial hyperreactivity (BHR; PC20 ≤1 mg·mL−1) at recruitment between 1995 and 1999. Logistic regression analyses, presented as unadjusted and adjusted for sex, age, family history of asthma, body mass index and smoking habits at recruitment. PC20: provocative concentration causing a 20% fall in FEV1.
Tables
- TABLE 1
Classification of asthma control according to Global Initiative for Asthma 2006
Controlled Partly controlled Uncontrolled (all of the below) (any of the below) (at least 3 of the below) During the last 4 weeks: Asthma symptoms during the day Twice or less per week Three times or more per week Three times or more per week Limitation of daily activities No Yes Yes Asthma symptoms during the night No Yes Yes Reliever medication Used twice or less per week Used three times or more per week Used three times or more per week Lung function FEV1 >80% predicted FEV1 <80% predicted FEV1 <80% predicted During the last 12 months: Exacerbations# No At least one At least one #: any of the following events in the last 12 months due to asthma: oral corticosteroids and/or antibiotics, emergency healthcare visit with or without hospitalisation, or not being able to work or perform daily activities due to asthma during at least 2 days. FEV1: forced expiratory volume in 1 s. Reproduced from [29] with permission.
- TABLE 2
Basic and clinical characteristics at recruitment between 1995 and 1999, comparing subjects in remission and subjects with persistent asthma at follow-up
All Persistent asthma Remission p-value Subjects n 205 182 23 Female sex 134 (65.4) 121 (66.5) 13 (56.5) 0.344 Age at asthma onset 39.3±10.3 39.4±10.2 38.6±11.6 0.718 BMI 25.9±4.5 25.9±4.4 26.7±4.7 0.386 Family history of asthma 83 (40.5) 77 (42.3) 6 (26.1) 0.135 BMI classification Normal weight 95 (46.3) 85 (46.7) 10 (43.5) Overweight 79 (38.5) 70 (38.5) 9 (39.1) Obesity 31 (15.1) 27 (14.8) 4 (17.4) 0.717+ Smoking habits Nonsmoker 105 (51.2) 95 (52.2) 10 (43.5) Ex-smoker 64 (31.2) 57 (31.3) 7 (30.4) Current smoker 36 (17.6) 30 (16.5) 6 (26.1) 0.276+ Occupational exposure to gas, dust or fumes 66 (33.3) 61 (34.9) 5 (21.7) 0.210 Educational level Primary school 21 (10.5) 20 (11.3) 1 (4.3) High school 92 (46.0) 81 (45.8) 11 (47.8) Higher education 87 (43.5) 76 (42.9) 11 (47.8) 0.417+ Lung function FEV1 % predicted 89.0±13.4 88.3±13.7 94.6±10.1 0.034 FVC % predicted 87.1±11.6 86.5±11.7 92.0±9.5 0.034 Bronchial hyperreactivity PC20# PC20 ≤1 mg·mL−1 89 (48.1) 83 (50.9) 6 (27.3) 0.037 PC20 ≤2 mg·mL−1 120 (64.9) 109 (66.9) 11 (50.0) 0.120 Atopic comorbidities Hay fever 82 (40.0) 73 (40.1) 9 (39.1) 0.928 Eczema 68 (33.2) 62 (34.1) 6 (26.1) 0.444 Nasal polyps 21 (10.2) 20 (11.0) 1 (4.3) 0.285 Positive skin-prick test¶ 85 (42.1) 75 (41.9) 10 (43.5) 0.885 Data are presented as n (%) or mean±sd, unless otherwise stated. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; PC20: provocative concentration causing a 20% fall in FEV1. #: among the 185 participating in metacholine challenge test at recruitment; ¶: among the 202 participating in skin-prick test; +: analysis performed in a 3×2 table. Bold values indicate p<0.05.
- TABLE 3
Changes in BMI, weight and smoking habits from recruitment to follow-up, and lung function, blood neutrophils and eosinophils and allergic sensitisation at follow-up between 2012 and 2014, comparing subjects in remission and subjects with persistent asthma
Persistent asthma Remission p-value Subjects n 182 23 Changes in BMI and weight BMI change 3.0±3.3 1.6±3.3 0.054 % weight change 10.3±0.1 4.9±0.1 0.059 Weight loss 23 (12.6) 6 (26.1) Stable weight 28 (15.4) 5 (21.7) Weight gain 131 (72.0) 12 (52.2) 0.118+ Changes in smoking habits Nonsmoker to nonsmoker 90 (49.5) 10 (43.5) Ex-smoker to ex-smoker (mean 11.9 pack-years) 57 (31.3) 7 (30.4) Ex-smoker to smoker 0 0 Smoker to smoker (mean 21.1 pack-years) 9 (4.9) 4 (17.4) Smoker to ex-smoker (mean 8.7 pack-years) 26 (14.3) 2 (8.7) 0.753§ Pack-years at follow-up 11.4 (11.7) 17.7 (12.2) 0.074 Lung function at follow-up FEV1 pp 89.0±14.0 96.7±11.8 0.014 FVC pp 94.6±14.2 101.1±14.5 0.043 FEV1 reversibility ≥12% and ≥200 mL 12 (7.1) 1 (4.5) 0.547 Blood neutrophils 109·L−1 at follow-up# ≥4 67 (39.4) 8 (34.8) 0.669 ≥5 21 (12.4) 3 (13.0) 0.570 ≥6 9 (5.3) 2 (8.7) 0.386 mean±sd 3.8±1.2 4.0±2.2 0.406 Blood eosinophils 109·L−1 at follow-up# ≥0.2 80 (47.1) 12 (52.2) 0.645 ≥0.3 39 (22.9) 4 (17.4) 0.383 ≥0.4 23 (13.5) 2 (8.7) 0.399 mean±sd 0.2±0.2 0.2±0.1 0.547 Allergic sensitisation at follow-up¶ Specific IgE >0.35 IU·mL−1 50 (28.4) 5 (21.7) 0.501 Sensitisation to any pollen 37 (21.0) 5 (21.7) 0.937 Sensitisation to any furry animal 30 (17.0) 4 (17.4) 0.580 Data are presented as n (%) or mean±sd, unless otherwise stated. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; Ig: immunoglobulin. #: among the 193 participating in blood sampling for cell count at follow-up; ¶: among the 199 participating in blood samples for IgE at follow-up; +: analysis performed in a 3×2 table; §: analysis performed in a 5×2 table. Bold values indicate p<0.05.
- TABLE 4
Characteristics of subjects with persistent asthma at follow-up, by asthma control classified according to Global Initiative for Asthma 2006 [29] criteria
Controlled asthma Partly controlled asthma Uncontrolled asthma p-value Subjects n 100 58 24 Female sex 63 (63.0) 40 (69.0) 18 (75.0) 0.476 Age at follow-up 53.7±9.7 55.7±10.4 56.3±10.1 0.327 Age at asthma onset 38.2±10.0 40.7±10.5 41.1±10.3 0.232 BMI 28.8±5.1 29.3±6.0 28.0±3.5 0.579 BMI classification Normal weight 19 (19.0) 13 (22.4) 7 (29.2) Overweight 50 (50.0) 19 (32.8) 10 (41.7) Obesity 31 (31.0) 26 (44.8) 7 (29.2) 0.216+ Smoking habits and occupational exposure Nonsmoker 50 (50.0) 28 (48.3) 12 (50.0) Ex-smoker 45 (45.0) 27 (46.6) 11 (45.8) Current smoker 5 (5.0) 3 (5.2) 1 (4.2) 0.999§ Pack-years 11.3±12.0 12.1±11.1 9.8±12.5 0.846 Occupational exposure to gas, dust or fumes 36 (37.1) 14 (24.6) 11 (52.4) 0.057 Lung function Pre-bronchodilator FEV1 pp 91.9±11.4 85.0±15.4 86.6±17.6 0.008 Pre-bronchodilator FVC pp 97.4±12.6 91.1±15.1 91.7±16.1 0.015 Pre-bronchodilator FEV1/FVC <0.70 29 (29.9) 22 (37.9) 8 (33.3) 0.588 AfterFEV1/FVC <0.70 13 (14.0) 15 (26.8) 4 (19.0) 0.153 FEV1 reversibility ≥12% and ≥200 mL 5 (5.4) 6 (10.7) 1 (4.8) 0.425 Comorbidities Current allergic rhinitis 37 (37.0) 29 (50.0) 10 (41.7) 0.279 Current eczema 18 (18.0) 11 (19.0) 5 (20.8) 0.948 Reflux 39 (39.0) 25 (43.1) 10 (41.7) 0.875 Nasal polyps 8 (7.1) 5 (8.6) 0 0.350 Blood neutrophils 109·L−1# ≥4 34 (37.4) 18 (32.1) 15 (65.2) 0.020 ≥5 10 (11.0) 5 (8.9) 6 (26.1) 0.092 ≥6 3 (3.3) 3 (5.4) 3 (13.0) 0.176 mean±sd 3.7 (1.1) 3.6 (1.2) 4.4 (1.5) 0.017 Blood eosinophils 109·L−1# ≥ 0.2 40 (44.0) 30 (53.6) 10 (43.5) 0.491 ≥0.3 16 (17.6) 17 (30.4) 6 (26.1) 0.187 ≥0.4 8 (8.8) 11 (19.6) 4 (17.4) 0.147 mean±sd 0.2 (0.1) 0.2 (0.2) 0.2 (0.2) 0.146 Allergic sensitisation¶ Specific IgE >0.35 IU·mL−1 27 (27.8) 18 (32.7) 5 (20.8) 0.550 Sensitisation to any pollen 19 (19.6) 15 (27.3) 3 (12.5) 0.292 Sensitisation to any furred animal 17 (17.5) 10 (18.2) 3 (12.5) 0.812 Data are presented as n (%) or mean±sd, unless otherwise stated. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; Ig: immunoglobulin. #: among the 170 participating in blood sampling for cell count; ¶: among the 176 participating in blood sampling for IgE; +: analysis performed in a 3×3 table. Bold values indicate p<0.05.
- TABLE 5
Any respiratory symptoms and use of asthma medication classified according to asthma treatment among subjects with persistent asthma, by asthma control classified according to Global Initiative for Asthma 2006 criteria [29] at follow-up
All# Controlled asthma Partly controlled asthma Uncontrolled asthma p-value Subjects n 182 100 58 24 Any respiratory symptoms at follow-up 164 (90.1) 88 (88.0) 52 (89.7) 24 (100.0) 0.207 Treatment at follow-up No treatment 36 (19.8) 28 (28.0) 8 (13.8) 0 (0) SABA or LABA without ICS 24 (13.2) 16 (16.0) 7 (12.1) 1 (4.2) ICS with SABA or LABA periodically 28 (15.4) 17 (17.0) 9 (15.5) 2 (8.3) Low-dose ICS without LABA most days per week 20 (11.0) 9 (9.0) 9 (15.5) 2 (8.3) Low-dose ICS and LABA most days per week 17 (9.3) 7 (7.0) 5 (8.6) 5 (20.8) Medium/high-dose ICS and LABA most days per week 57 (31.3) 23 (23.0) 20 (34.5) 14 (58.3) 0.004 Data are presented as n (%), unless otherwise stated. SABA: short-acting β2 agonist; LABA: long-acting β2 agonist; ICS: inhaled corticosteroid. #: n=182. Bold values indicate p<0.05.
