Decline in FEV1 and FVC over a 20-year follow-up in British men aged 40–59 years in 1978–1980 according to adult social class
| Adult social class | Age-adjusted | Adjusted for age and baseline values | Further adjusted for baseline cigarette smoking | Further adjusted for baseline BMI, physical activity, bronchitis, asthma |
| Mean change in FEV1 in litres (SE) (N=4005) | ||||
| Social class I (n=399) | −0.74 (0.03) | −0.73 (0.02) | −0.77 (0.02) | −0.77 (0.02) |
| Social class II (n=1106) | −0.79 (0.02) | −0.79 (0.01) | −0.81 (0.01) | −0.81 (0.01) |
| Social class III NM (n=414) | −0.85 (0.03) | −0.84 (0.02) | −0.85 (0.02) | −0.86 (0.02) |
| Social class III manual (n=1614) | −0.91 (0.01) | −0.91 (0.01) | −0.90 (0.01) | −0.90 (0.01) |
| Social class IV (n=355) | −0.98 (0.03) | −1.01 (0.03) | −0.99 (0.03) | −0.98 (0.02) |
| Social class V (n=117) | −0.97 (0.05) | −0.96 (0.04) | −0.94 (0.04) | −0.94 (0.04) |
| p for trend* | <0.001 | <0.001 | <0.001 | <0.001 |
| Non-manual (n=1919) | −0.80 (0.01) | −0.79 (0.01) | −0.81 (0.01) | −0.81 (0.01) |
| Manual (n=2086) | −0.93 (0.01) | −0.93 (0.02) | −0.91 (0.01) | −0.91 (0.01) |
| Mean difference (95% CI) Manual versus non-manual | −0.13 (−0.16 to −0.10) | −0.14 (−0.17 to −0.11) | −0.10 (−0.13 to −0.07) | −0.10 (−0.13 to −0.07) |
| Mean change in FVC in litres (SE) (N=4008) | ||||
| Social class I (n=399) | −1.02 (0.03) | −0.99 (0.03) | −1.03 (0.03) | −1.03 (0.03) |
| Social class II (n=1107) | −1.06 (0.02) | −1.05 (0.02) | −1.06 (0.02) | −1.06 (0.02) |
| Social class III NM (n=414) | −1.13 (0.03) | −1.13 (0.03) | −1.14 (0.03) | −1.14 (0.03) |
| Social class III manual (n=1614) | −1.14 (0.02) | −1.15 (0.02) | −1.14 (0.02) | −1.14 (0.02) |
| Social class IV (n=355) | −1.21 (0.03) | −1.24 (0.03) | −1.22 (0.03) | −1.21 (0.03) |
| Social class V (n=119) | −1.18 (0.06) | −1.20 (0.06) | −1.17 (0.06) | −1.18 (0.06) |
| p for trend* | <0.001 | <0.001 | <0.001 | <0.001 |
| Non-manual (n=1920) | −1.07 (0.01) | −1.05 (0.01) | −1.07 (0.01) | −1.07 (0.01) |
| Manual (n=2088) | −1.16 (0.01) | −1.17 (0.01) | −1.15 (0.01) | −1.15 (0.01) |
| Mean difference (95% CI) Manual versus non-manual | −0.09 (−0.13 to −0.05) | −0.12 (−0.15 to −0.08) | −0.09 (−0.12 to −0.04) | −0.08 (−0.12 to −0.04) |
↵* p for trend from models with social class as a continuous variable.