Multivariable associations between doctor-diagnosed childhood pneumonia-pleurisy, FEV1 and measures of airflow obstruction from childhood to middle age
| Episodes of pneumonia and/or pleurisy† | Complete case (n) | Measures of airflow obstruction at ages 7, 45 and 53 years ‡§ | |||||
| FEV1 | FEV1:FVC | FEV1:FVC <LLN | |||||
| (z-score (SD, 95% CI)) | P value | (z-score (SD, 95% CI)) | P value | OR (95% CI) | P value | ||
| At age 7 | |||||||
| 0 | 5390 | Ref | Ref | Ref | |||
| ≥1 | 852 | −0.03 (−0.1 to +0.04) | 0.373 | −0.09 (−0.2 to 0.02)* | 0.012 | 1.31 (0.9 to 1.9) | 0.134 |
| 1–2 | 767 | −0.01 (−0.1 to +0.1) | 0.821 | −0.08 (−0.2 to 0.01)* | 0.033 | 1.16 (0.8 to 1.7) | 0.455 |
| >2 | 85 | −0.25 (−0.5 to 0.04)* | 0.021 | −0.18 (−0.4 to +0.03) | 0.085 | 2.71 (1.3 to 5.7)** | 0.009 |
| At age 45 | |||||||
| 0 | 984 | Ref | Ref | Ref | |||
| ≥1 | 210 | −0.07 (−0.2 to +0.1) | 0.362 | +0.16 (+0.01 to +0.3) | 0.040 | 0.82 (0.5 to 1.4) | 0.472 |
| 1–2 | 189 | −0.03 (−0.2 to +0.1) | 0.726 | +0.20 (+0.04 to +0.4)* | 0.015 | 0.70 (0.4 to 1.3) | 0.252 |
| >2 | 21 | −0.48 (−0.9 to 0.01)* | 0.045 | −0.18 (−0.6 to +0.3) | 0.425 | 1.93 (0.6 to 6.1) | 0.264 |
| At age 53 | |||||||
| 0 | 2064 | Ref | Ref | Ref | |||
| ≥1 | 312 | −0.17 (−0.3 to 0.1)** | 0.008 | −0.09 (−0.2 to +0.02) | 0.145 | 1.32 (0.8 to 2.2) | 0.336 |
| 1–2 | 287 | −0.16 (−0.3 to 0.03)* | 0.014 | −0.09 (−0.2 to +0.02) | 0.165 | 1.30 (0.7 to 2.3) | 0.395 |
| >2 | 25 | −0.23 (−0.6 to +0.2) | 0.261 | −0.10 (−0.5 to +0.2) | 0.615 | 1.55 (0.4 to 6.8) | 0.569 |
If a statistical interaction is present, stratified results have been presented in the main text and correspond to online supplementary table E5 (by current childhood asthma), online supplementary table E6 (by participant sex) and online supplementary table E7 (by never/ever smoking).
*P<0.05, **p<0.01, ***p<0.001.
†≥1 and >2 episodes refer to childhood pneumonia/pleurisy-ever and recurrent pneumonia/pleurisy in the main text, respectively.
‡Airflow obstruction without inhaled bronchodilator at age 7; post-bronchodilator airflow obstruction assessed at ages 45 and 53 years.
§Multivariable adjustments include sampling weights (at age 45), maternal/paternal smoking,socioeconomic status (paternal occupation, rurality of primary school) and breast/bottle feeding.
FEV1:FVC, the ratio between FEV1 and FVC; LLN, lower limit of normal; Ref, reference.