Characteristics for subjects stratified by BMI-category and physician-diagnosed asthma
| No physician-diagnosed asthma | Physician-diagnosed asthma | P value | |||||
| Normal weight (BMI <25 kg/m2) | Overweight (BMI 25–29.9 kg/m2) | Obesity (BMI ≥30 kg/m2) | Normal weight (BMI <25 kg/m2) | Overweight (BMI 25–29.9 kg/m2) | Obesity (BMI ≥30 kg/m2) | (Comparing all strata) | |
| (n=309) | (n=255) | (n=127) | (n=228) | (n=230) | (n=168) | ||
| Sex | <0.001* | ||||||
| Women, N (%) | 216 (70%) | 132 (52%) | 62 (49%) | 157 (69%) | 125 (54%) | 110 (66%) | |
| Men N (%) | 93 (30%) | 123 (48%) | 65 (51%) | 71 (31%) | 105 (46%) | 58 (35%) | |
| Smoking status | 0.16* | ||||||
| Never smoker N (%) | 183 (59%) | 140 (55%) | 55 (43%) | 134 (59%) | 111 (48%) | 83 (49%) | |
| Former smoker N (%) | 68 (22%) | 63 (25%) | 39 (31%) | 53 (23%) | 65 (28%) | 47 (28%) | |
| Occasional smoker N (%) | 27 (9%) | 25 (10%) | 10 (8%) | 17 (8%) | 21 (9%) | 13 (8%) | |
| Daily smoker N (%) | 31 (10%) | 27 (11%) | 23 (18%) | 24 (11%) | 33 (14%) | 25 (15%) | |
| Highest completed education | 0.24* | ||||||
| Elementary N (%) | 35 (11%) | 30 (12%) | 18 (14%) | 37 (16%) | 27 (12%) | 24 (14%) | |
| Upper secondary N %) | 98 (32%) | 106 (42%) | 52 (41%) | 81 (36%) | 87 (38%) | 76 (45%) | |
| University N (%) | 165 (53%) | 111 (44%) | 54 (43%) | 102 (45%) | 108 (47%) | 65 (39%) | |
| Other/missing N (%) | 11 (4%) | 8 (3%) | 3 (2%) | 8 (4%) | 8 (4%) | 3 (2%) | |
| Age at examination, years, SEM categories, SD total | 39.4 (0.55) | 42.7 (0.48) | 42.4 (0.74) | 36.1 (0.68) | 42.3 (0.63) | 42.1 (0.59) | <0.001** |
| Age of onset of asthma symptoms, years of age | NA | NA | NA | 13.1 (0.75) | 16.2 (0.88) | 16.6 (0.89) | 0.005** |
Current use of any asthma medication (spray, inhalation powder or tablets)
| NA NA | NA NA | NA NA | 109 (48%) 119 (52%) | 103 (45%) 127 (55%) | 59 (35%) 109 (65%) | 0.036* |
ACT score
| NA NA | NA NA | NA NA | 109 (72%) 45 (29%) | 84 (65%) 45 (35%) | 63 (57%) 48 (43%) | 0.034* |
| Ever had sarcoidosis, yes N (%) | 1 | 0 | 3 | 0 | 3 | 2 | 0.051* |
| Ever sought help for mental problems, yes N (%) | 50 (19%) | 44 (21%) | 23 (18%) | 56 (25%) | 55 (24%) | 46 (27%) | 0.014* |
| Ever had other chronic lung diseases than asthma and COPD, yes N (%) | 1 | 4 | 3 | 12 (5%) | 25 (11%) | 12 (7%) | <0.001* |
| Physician-diagnosed COPD, yes N (%) | 1 | 1 | 0 | 7 | 6 | 6 | 0.006* |
| Allergy with respiratory symptoms, yes N (%) | 98 (32%) | 76 (30%) | 43 (34%) | 138 (61%) | 134 (58%) | 112 (67%) | <0.001* |
P values are calculated using *χ2 or ** One.way analysis of variance (ANOVA). NA=not applicable. Statistically significant findings, p<0.05, are bolded
ACT, Asthma Control Test; BMI, body mass index; COPD, Chronic obstructive pulmonary disease.