Description of the study population in 1999
| Dairy farmers (n=215) | Control subjects (n=110) | p value* | |
|---|---|---|---|
| *χ2 tests for qualitative variables; Student’s t tests for quantitative variables. | |||
| †n=209 for dairy farmers; n=104 for controls. | |||
| Age, y | |||
| Mean (SD) | 51.7 (11.6) | 43.9 (10.7) | <0.001 |
| Height | |||
| Male, mean (SD) | 174.2 (5.9) | 176.3 (6.8) | <0.05 |
| Female, mean (SD) | 161.6 (6.1) | 162.5 (5.7) | NS |
| Smoking | |||
| Smokers, >10 pack years, n (%) | 15 (6.9) | 14 (12.7) | <0.001 |
| Smokers, ⩽10 pack years, n (%) | 10 (4.7) | 10 (9.1) | |
| Ex-smokers, n (%) | 27 (12.6) | 28 (25.5) | |
| Non-smokers, n (%) | 163 (75.8) | 58 (52.7) | |
| Mean pack-years (SD) | 18.3 (16.3) | 13.4 (9.5) | NS |
| Passive smoking, n (%) | 22 (13.7) | 12 (20.7) | NS |
| Alcohol† | |||
| <10 g, n (%) | 116 (55.5) | 70 (67.3) | NS |
| 10–50 g, n (%) | 88 (42.1) | 33 (31.7) | |
| >50 g, n (%) | 5 (2.4) | 1 (1.0) | |