Sociodemographic and clinical characteristics at age 53 of TAHS participants
| Clinical characteristic at age 53 years | TAHS participants attending follow-up at age 53*† | ||||
| None | Childhood bronchitis by age 7 years | P trend | |||
| Non-recurrent | Recurrent, non-protracted | Recurrent- protracted | |||
| Clinical feature (n (%)), N=3202 | 1680 (52.5) | 902 (28.1) | 578 (18.1) | 42 (1.3) | – |
| Age (years, SD) | 53.0 (1.0) | 53.0 (0.9) | 53.0 (0.9) | 53.2 (1.0) | 0.100 |
| Sex (% male) | 796 (47) | 432 (48) | 327 (56) | 23 (55) | 0.004 |
| Ever-smokers | 1008 (60) | 520 (58) | 325 (56) | 35 (83) | 0.045 |
| Pack-years (median (IQR)) | 12.9 (3.9–29) | 14.7 (3.4–29) | 12.8 (2.5–30) | 11.1 (7.5–37) | 0.394 |
| Current smokers | 313 (19) | 145 (16) | 91 (16) | 7 (17) | 0.075 |
| Usual cough ≥3 months | 158 (9.4) | 92 (10.3) | 62 (10.7) | 8 (19) | 0.117 |
| Usual phlegm ≥3 months | 94 (5.6) | 47 (5.3) | 38 (6.6) | 5 (12) | 0.231 |
| Chronic bronchitis-current | 81 (5.0) | 40 (4.6) | 32 (5.9) | 5 (12) | 0.070 |
| Chronic bronchitis-ever | 137 (8.5) | 72 (8.3) | 59 (11) | 7 (17) | 0.245 |
| Doctor-diagnosed current asthma | 151 (9.0) | 116 (13) | 114 (20) | 14 (33) | <0.001 |
| Doctor-diagnosed asthma-ever | 317 (19) | 221 (25) | 238 (41) | 28 (67) | <0.001 |
| Aged ≥7 years‡ | 313 (19) | 221 (25) | 218 (38) | 28 (67) | <0.001 |
| Doctor-diagnosed pneumonia-ever | 238 (14) | 174 (19) | 146 (25) | 15 (36) | <0.001 |
| Aged ≥7 years‡ | 204 (12) | 135 (15) | 111 (19) | 9 (21) | <0.001 |
| Hospitalisation-ever | 73 (4.4) | 59 (6.7) | 63 (11) | 2 (4.8) | <0.001 |
| Spirometry (n (%)) N=2379§ | 1238 (52.0) | 686 (28.8) | 427 (17.9) | 28 (1.2) | – |
| Pre-BD zFEV1 | –0.04 (2.0) | –0.08 (2.6) | –0.24 (1.2) | –0.19 (1.0) | 0.016 |
| Post-BD zFEV1 | +0.16 (1.0) | +0.07 (1.0) | –0.02 (1.2) | +0.06 (0.9) | 0.005 |
| BDR Δ FEV1 (mL (SD)) | 109 (129) | 104 (135) | 111 (135) | 110 (127) | 0.766 |
| Pre-BD zFVC | +0.10 (1.5) | +0.07 (2.1) | –0.03 (1.0) | +0.08 (1.0) | 0.144 |
| Post-BD zFVC | +0.10 (0.9) | +0.03 (0.9) | +0.01 (1.0) | +0.09 (0.9) | 0.100 |
| BDR Δ FVC (mL (SD)) | 19 (147) | 13 (160) | 33 (157) | 13 (148) | 0.310 |
| Pre-BD zFEV1/FVC | –0.28 (0.9) | –0.32 (0.9) | –0.39 (1.0) | –0.49 (0.7) | 0.042 |
| Pre-BD airflow obstruction¶ | 88 (7.1) | 54 (7.9) | 48 (11) | 1 (4) | 0.033 |
| Post-BD zFEV1/FVC | +0.07 (0.9) | +0.04 (0.9) | –0.07 (1.0) | –0.09 (0.7) | 0.016 |
| Post-BD airflow obstruction¶ | 48 (3.9) | 30 (4.4) | 24 (5.7) | 1 (4) | 0.077 |
| Post-BD spirometric restriction¶ | 23 (1.9) | 17 (2.5) | 13 (3.1) | 0 (0) | 0.242 |
| Transfer factor (n (%)) N=2281§ | 1194 (52.3) | 647 (28.4) | 412 (18.1) | 28 (1.2) | – |
| CO transfer factor (zTLco) | +0.14 (0.9) | +0.17 (1.0) | +0.23 (1.0) | +0.67 (1.0) | 0.008 |
| CO transfer coefficient (zKco) | +0.23 (1.0) | +0.28 (1.0) | +0.41 (1.0) | +0.79 (1.1) | <0.001 |
| Alveolar volume (zVA) | –0.09 (1.0) | –0.11 (1.0) | –0.19 (0.9) | –0.07 (1.0) | 0.071 |
*Clinical and lung function variables are expressed by n(%) and z-score (SD), respectively, unless otherwise specified.
†Participant numbers differ by questionnaire, spirometry and transfer factor measurements as indicated in italics.
‡Doctor-diagnosed asthma | pneumonia recalled after childhood bronchitis was assessed that is, after age 7.
§By definition, z-scores that are measured in SD units haves a mean of 0 and SD of 1.
¶Airflow obstruction was defined by FEV1/FVC <LLN; spirometric restriction by post-BD FVC <LLN and FEV1/FVC ≥LLN.
BD, bronchodilator; BDR, bronchodilator response; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; Kco, carbon monoxide transfer coefficient; LLN, lower limit of normal; TAHS, Tasmanian Longitudinal Health Study; TLco, transfer factor for carbon monoxide of the lung; VA, alveolar volume; z, z-score.