Models detailing associations between parental respiratory disease history, individual life-course factors and symptomatic airflow obstruction (outcome), by category (smoking, social class, asthma and others)
| Life-course factors | Model 1a | Model 1b | Model 1c | Model 1d |
| Smoking | ||||
| Parental respiratory disease history | 1.87 (1.21–2.89)* | 1.71 (1.09–2.68)* | 1.69 (1.08–2.64)* | 1.70 (1.09–2.65)* |
| Passive smoke childhood | 1.46 (1.15–1.85)** | 1.23 (0.97–1.58) | ||
| Adulthood smoking | ||||
| Ever smoker | 1.79 (1.34–2.38)*** | 1.77 (1.33–2.36)*** | ||
| Persistent smoker | 4.93 (3.88–6.28)*** | 4.81 (3.78–6.10)*** | ||
| Cumulative smoke exposure | ||||
| 0 (never) | 1.00 (ref.) | |||
| 1 | 1.03 (0.67–1.59) | |||
| 2 | 1.14 (0.74–1.76) | |||
| 3 | 2.72 (1.80–4.10)*** | |||
| 4 (persistent) | 5.33 (3.55–8.00)*** | |||
| Total indirect effects estimates (se) | 0.027 (0.014) | 0.104 (0.047)* | 0.117 (0.048)* | 0.123 (0.044)* |
| Model 2a | Model 2b | Model 2c | Model 2d | |
| SC | ||||
| Parental respiratory disease history | 1.88 (1.21–2.92)* | 1.82 (1.17–2.83)* | 1.80 (1.16–2.79)* | 1.76 (1.13–2.73)* |
| At birth | ||||
| SC1 | 1.00 (ref.) | |||
| SC2 | 1.15 (0.76–1.75) | |||
| SC3 | 1.15 (0.86–1.54) | |||
| SC4 | 1.30 (0.93–1.81) | |||
| At 11 years of age | ||||
| SC1 | 1.00 (ref.) | |||
| SC2 | 0.68 (0.43–1.08) | |||
| SC3 | 1.13 (0.86–1.47) | |||
| SC4 | 1.28 (0.95–1.73) | |||
| At 42 years of age | ||||
| SC1 | 1.00 (ref.) | |||
| SC2 | 1.34 (0.99–1.81) | |||
| SC3 | 1.73 (1.30–2.31)*** | |||
| SC4 | 1.94 (1.44–2.62)*** | |||
| Cumulative SC | 1.09 (1.04–1.14)*** | |||
| Total indirect effects estimates (se) | 0.020 (0.015) | 0.051 (0.027) | 0.063 (0.022)** | 0.088 (0.028)*** |
| Model 3a | Model 3b | Model 3c | Model 3d | |
| Asthma | ||||
| Parental respiratory disease history | 1.83 (1.18–2.83)* | 1.54 (0.96–2.47) | 1.53 (0.96–2.45) | 1.62 (1.03–2.55)** |
| Childhood asthma | 2.17 (1.74–2.70)*** | 1.30 (1.02–1.67)** | ||
| Adulthood asthma | 6.12 (4.89–7.64)*** | 5.59 (4.39–7.11)*** | ||
| Cumulative asthma | ||||
| 0 (never) | 1.00 (ref.) | |||
| 1 | 2.53 (1.98–3.24)*** | |||
| 2 (persistent) | 7.22 (5.44–9.59)*** | |||
| Total indirect effects estimates (se) | 0.041 (0.024) | 0.180 (0.052)** | 0.185 (0.053)*** | 0.150 (0.048)** |
| Model 4a | Model 4b | Model 4c | Model 4d | |
| Others | ||||
| Parental respiratory disease history | 1.88 (1.21–2.91)* | 1.90 (1.22–2.94)** | 1.87 (1.20–2.90)* | 1.85 (1.19–2.87)* |
| Low birth weight | 1.34 (0.87–2.05) | |||
| Pneumonia (childhood) | 1.79 (1.16–2.77)* | 1.78 (1.15–2.75)* | ||
| Occupational exposure | 1.39 (1.11–1.76)* | 1.39 (1.10–1.75)* | ||
| Total indirect effects estimates (se) | 0.016 (0.014) | 0.008 (0.010) | 0.021 (0.014) | 0.029 (0.017) |
Data are presented as OR (95% CI) unless otherwise stated. All models were adjusted for sex and recent chest infection (past 3 weeks prior to when spirometry was performed at age 45 years). SC: social class (SC1: professional/managerial; SC2: unskilled nonmanual; SC3: skilled manual; SC4: unskilled manual). *: p<0.05; **: p<0.005; ***: p<0.001.