Main characteristics of study participants, by sex and asthma status
| Characteristics | Women (n=123 921) | Men (n=132 498) | ||
| Controls (n=109 865) | Asthma (n=14 056) | Controls (n=118 251) | Asthma (n=14 247) | |
| Age at recruitment (years) | 55.4±8.0 | 54.3±8.1* | 56.4±8.1 | 55.3±8.4* |
| Caucasian ethnicity | 104 642 (95.3) | 13 301 (94.6)* | 112 602 (95.2) | 13 598 (95.4) |
| Annual household income < £31 000 | 54 863 (49.9) | 7077 (50.4) | 52 906 (44.7) | 6172 (43.2)* |
| BMI (kg/m2) | 27.0±5.1 | 28.4±6.0* | 27.8±4.2 | 28.0±4.4* |
| Obesity (BMI ≥30 kg/m2) | 25 807 (23.5) | 4545 (32.3)* | 29 624 (25.1) | 3919 (27.5)* |
| Smoking status | ||||
| Never | 75 812 (69.0) | 9506 (67.6)* | 69 392 (58.7) | 8558 (60.1)* |
| Former | 24 056 (21.9) | 3258 (23.2) | 35 436 (30.0) | 4330 (30.4) |
| Current | 9997 (9.1) | 1292 (9.2) | 13 423 (11.4) | 1359 (9.5) |
| Pack-years of smoking | 6.1±12.3 | 6.7±13.4* | 10.6±18.2 | 10.3±18.6 |
| Current use of OC or HRT | 8023 (7.3) | 1212 (8.6)* | – | – |
| Had menopause | 75 474 (68.7) | 8966 (63.8)* | – | – |
| Free testosterone (pmol/L) | 11.9±8.8 | 11.4±8.6* | 164.9±60.1 | 163.2±61.7* |
| Estradiol (pmol/L) | 241.4±302.7 | 259.1±314.6* | 132.9±0.1 | 133.2±0.4 |
| FEV1 (mL)† | 2500±489 | 2359±506* | 3368±660 | 3099±726* |
| FVC (mL)† | 3266±593 | 3179±606* | 4457±794 | 4331±842* |
| FEV1/FVC (%)† | 76.7±5.4 | 74.1±6.6* | 75.5±6.3 | 70.9±8.2* |
| Wheeze in the last year | – | 8826 (63.7) | – | 9341 (66.5) |
| At least one asthma hospitalisation | – | 484 (3.6) | – | 354 (2.6) |
Results are shown as mean±SD for continuous variables, and as N (%) for binary variables.
*p<0.05 for comparison of participants with current asthma versus controls.
†Numbers (%) may vary due to missingness.
BMI, body mass index; HRT, hormone replacement therapy; OC, oral contraceptives.