Characteristics of the study groups
| Early-onset (n=191) | Late-onset (n=127) | Remitted (n=582) | Never asthma (n=408) | Early-onset vs late-onset | |
|---|---|---|---|---|---|
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | MD (95% CI) | |
| BMI, kg/m2 | 29.1 (6.6) | 29.1 (6.9) | 28.9 (6.5) | 27.2 (5.6) | −0.01 (−1.52 to 1.50) |
| N (%) | N (%) | N (%) | N (%) | RR (95% CI) | |
| Female | 95 (50) | 90 (71) | 266 (46) | 198 (49) | 0.70 (0.59 to 0.84)† |
| Smoking status | |||||
| Never | 93 (49) | 49 (39) | 226 (39) | 181 (44) | – |
| Former | 56 (29) | 34 (27) | 185 (32) | 120 (29) | 0.87 (0.50 to 1.50) |
| Pack-years, median [IQR] | 6.8 [1.2–11.9] | 8.4 [2.2–25.5] | 6.3 [2.0–16.3] | 7.9 [2.0–14.4] | |
| Current | 41 (22) | 44 (35) | 170 (29) | 107 (26) | 0.49 (0.28 to 0.85)* |
| Pack-years, median [IQR] | 22.9 [17.6–29.0] | 24 [10.2–32.0] | 20.3 [9.6–28.8] | 21 [12.0–28.0] | |
| Social class | |||||
| 1 (highest) | 57 (30) | 29 (23) | 173 (30) | 112 (28) | – |
| 2 | 16 (8) | 14 (11) | 67 (12) | 54 (13) | 0.58 (0.25 to 1.35) |
| 3 | 42 (22) | 13 (10) | 125 (22) | 83 (20) | 1.64 (0.76 to 3.54) |
| 4 | 34 (18) | 31 (25) | 103 (18) | 71 (18) | 0.56 (0.29 to 1.08) |
| 5 | 40 (21) | 39 (31) | 111 (19) | 85 (21) | 0.52 (0.28 to 0.98)* |
| FH asthma | 132 (71) | 59 (49) | 311 (56) | 151 (38) | 1.45 (1.18 to 1.78)† |
| Atopic | 153 (80) | 75 (59) | 329 (57) | 173 (42) | 1.36 (1.15 to 1.59)† |
| Rhinitis (ever) | 158 (83) | 108 (86) | 364 (63) | 180 (44) | 0.97 (0.88 to 1.07) |
| Eczema (ever) | 119 (63) | 70 (56) | 262 (45) | 124 (31) | 1.11 (0.92 to 1.35) |
| ICS (current) | 19 (10) | 10 (8) | – | – | 1.26 (0.61 to 2.63) |
| ICS+LABA (current) | 37 (19) | 16 (14) | – | – | 1.54 (0.89 to 2.64) |
*p<0.05; †p<0.001.
BMI, body mass index; FH, family history; ICS, inhaled corticosteroid; LABA, long-acting β2-receptor agonist; MD, mean difference; RR, risk ratio.
The bolded text identifies results reaching statistical significance (p<0.05).