Population characteristics
| Controls | Farmers (all) | Farmers (by category) | ||||||
| Crop | Cattle | Swine | Poultry | ≥2 types of livestock | Other farm production | |||
| Subjects | 917 | 3787 | 411 | 1638 | 233 | 192 | 333 | 980 |
| Males | 423 (46) | 2371 (63)* | 272 (66)* | 998 (61)* | 153 (66)* | 102 (53) | 209 (63)* | 637 (65)* |
| Age years | ||||||||
| 40–49 | 307 (34) | 1200 (32) | 164 (40)* | 450 (27)* | 73 (31) | 72 (38)* | 98 (29) | 343 (35) |
| 50–59 | 288 (31) | 1181 (31) | 134 (33)* | 501 (31)* | 86 (37) | 72 (38)* | 102 (31) | 286 (29) |
| ≥60 | 322 (35) | 1406 (37) | 113 (27)* | 687 (42)* | 74 (32) | 48 (24)* | 133 (40) | 351 (36) |
| BMI kg·m−2 | 25.7±4.4 | 26.8±4.5* | 26.5±4.4* | 27.1±4.7* | 26.1±3.8 | 26.0±4.2 | 26.4±3.7* | 27.1±4.7* |
| Smoking status | ||||||||
| Never | 540 (59) | 2571 (68)* | 237 (58) | 1227 (75)* | 169 (73)* | 127 (66) | 239 (72)* | 572 (58) |
| Former | 250 (27) | 736 (19)* | 94 (23)* | 261 (16)* | 49 (21)* | 36 (19) | 61 (18)* | 235 (24) |
| Current | 127 (14) | 480 (13)* | 80 (19)* | 150 (9)* | 15 (6)* | 29 (15) | 33 (10)* | 173 (18) |
| Smoking intensity | ||||||||
| <1 pack-year | 549 (60) | 2599 (69)* | 238 (58) | 1240 (76)* | 172 (74)* | 128 (67) | 241 (72)* | 580 (59) |
| 1–15 pack-years | 189 (21) | 542(14)* | 70 (17) | 194 (12)* | 35 (15)* | 25 (13) | 42 (13)* | 176 (18) |
| >15 pack-years | 179 (19) | 646(17)* | 103 (25) | 204 (12)* | 26 (11)* | 39 (20) | 50 (15)* | 224 (23) |
| Pack-years | 7.14±14.4 | 5.70±12.6* | 7.78±14.6 | 4.09±10.1* | 3.86±9.3* | 6.76±14.0 | 4.98±11.5* | 8.11±15.4 |
| Region | ||||||||
| Brittany | 796 (87) | 2925 (77)* | 327 (80)* | 1091 (67)* | 231 (99)* | 187 (97)* | 320 (96)* | 769 (78)* |
| Franche-Comté | 121 (13) | 862 (23)* | 84 (20)* | 547 (33)* | 2 (1)* | 5 (3)* | 13 (4)* | 211 (22)* |
| mMRC dyspnoea >0 | 165 (19) | 816 (22)* | 92 (23) | 352 (22)* | 34 (15) | 44 (24) | 50 (16) | 244 (26)* |
| Chronic cough | 106 (12) | 687 (19)* | 77 (19)* | 296 (19)* | 33 (15) | 31 (17) | 66 (21)* | 184 (19)* |
| Chronic sputum | 81 (9) | 538 (15)* | 52 (13)* | 247 (16)* | 22 (10) | 24 (13) | 48 (15)* | 145 (15)* |
| Atopy | 242 (27) | 954 (26) | 115 (29) | 366 (23)* | 58 (26) | 44 (24) | 93 (29) | 278 (29) |
| Pre-bronchodilator spirometry | ||||||||
| FEV1 L | 3.09±0.77 | 3.11±0.84 | 3.27±0.81* | 3.05±0.83 | 3.23±0.88* | 3.09±0.85 | 3.14±0.85 | 3.13±0.84 |
| z-score | 0.69±1.03 | 0.52±1.10* | 0.61±1.07 | 0.51±1.06* | 0.63±1.15 | 0.55±1.13 | 0.55±1.02* | 0.45±1.19* |
| FVC L | 3.87±0.97 | 3.94±1.02 | 4.11±0.98* | 3.84±1.01 | 4.05±1.04* | 3.91±0.97 | 3.99±1.06* | 3.98±1.00* |
| z-score | 0.92±1.04 | 0.74±1.07* | 0.83±1.04 | 0.71±1.05* | 0.81±1.11 | 0.85±1.09 | 0.79±1.03 | 0.70±1.13* |
| FEV1/FVC % | 80.2±6.6 | 79.2±7.3* | 79.5±7.0 | 79.4±7.0* | 79.6±7.6 | 79.0±7.0* | 79.0±6.6* | 78.7±7.9* |
| z-score | 0.36±0.95 | 0.25±1.04* | 0.25±0.99 | 0.31±1.00 | 0.32±1.09 | 0.16±0.97* | 0.24±1.07 | 0.18±1.11* |
| PEF L·s−1 | 7.60±2.05 | 7.64±2.18 | 7.97±2.19* | 7.49±2.13 | 7.91±2.09* | 7.60±2.05 | 7.67±2.28 | 7.71±2.22 |
| z-score | 0.46±1.33 | 0.21±1.41* | 0.35±1.41 | 0.17±1.35* | 0.35±1.28 | 0.22±1.45* | 0.20±1.47* | 0.19±1.49* |
| FEF25–75 L·s−1 | 3.08±1.10 | 3.03±1.18 | 3.20±1.21 | 2.98±1.16* | 3.18±1.30 | 2.98±1.10 | 3.01±1.16 | 3.02±1.20 |
| z-score | −0.24±1.00 | −0.35±1.02* | −0.29±1.06 | −0.35±0.99* | −0.24±1.11 | −0.43±0.94* | −0.37±0.98* | −0.39±1.05* |
Data are presented as n, n (%) or mean±sd, unless otherwise stated. BMI: body mass index; mMRC: modified Medical Research Council; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; PEF: peak expiratory flow; FEF25–75: forced expiratory flow at 25–75% of FVC. *: p<0.05 versus controls.