Demographic, medical and farming characteristics by adult-onset asthma status in 19,704 male farmers from the Agricultural Health Study
| Control | Allergic asthma | Nonallergic asthma | |
| Subjects n | 19263 | 127 | 314 |
| Age | |||
| 20–39 yrs | 5143 (27) | 19 (15) | 31 (10) |
| 40–49 yrs | 5003 (26) | 28 (22) | 68 (22) |
| 50–59 yrs | 4520 (24) | 33 (26) | 83 (26) |
| ≥60 yrs | 4597 (24) | 47 (37) | 132 (42) |
| US state | |||
| Iowa | 13046 (68) | 90 (71) | 226 (72) |
| North Carolina | 6217 (32) | 37 (29) | 88 (28) |
| Body mass index | |||
| <25 kg·m−2 | 5023 (26) | 25 (20) | 68 (22) |
| 25–29 kg·m−2 | 9874 (51) | 68 (54) | 157 (50) |
| ≥30 kg·m−2 | 4366 (23) | 34 (27) | 89 (28) |
| Smoking history | |||
| Never | 10408 (54) | 66 (52) | 145 (46) |
| Past | 6359 (33) | 54 (43) | 143 (46) |
| Current | 2496 (13) | 7 (6) | 26 (8) |
| Race | |||
| White | 18907 (98) | 125 (98) | 310 (99) |
| Other | 301 (2) | 2 (2) | 2 (1) |
| Education | |||
| High school graduate or less | 10811 (57) | 64 (53) | 198 (64) |
| Greater than high school | 8055 (43) | 58 (48) | 111 (36) |
| Grew up on a farm | 17728 (92) | 118 (93) | 287 (92) |
| Respiratory and allergic conditions | |||
| Farmer's lung | 386 (2) | 22 (17) | 32 (10) |
| Chronic bronchitis | 603 (3) | 33 (26) | 86 (28) |
| Allergy# | 1856 (10) | 127 (100) | 0 (0) |
| Eczema | 406 (2) | 36 (28) | 0 (0) |
| Hay fever | 1519 (8) | 105 (83) | 0 (0) |
| Wheeze | 3152 (17) | 105 (84) | 216 (70) |
| Runny nose in past year | 12413 (66) | 110 (88) | 224 (74) |
| Watery itchy eyes in past year | 6343 (34) | 85 (69) | 119 (40) |
| PPE use¶ 10 yrs before enrolment | |||
| Never used PPE | 4071 (21) | 24 (19) | 62 (20) |
| Cartridge respirator | 920 (5) | 11 (9) | 20 (6) |
| Dust mask | 2117 (11) | 20 (16) | 56 (18) |
| Chemical gloves | 6971 (36) | 49 (39) | 119 (38) |
| PPE use¶ at enrolment | |||
| Never use PPE | 1768 (9) | 15 (12) | 31 (10) |
| Cartridge respirator | 1827 (9) | 14 (11) | 25 (8) |
| Dust mask | 3937 (20) | 36 (28) | 95 (30) |
| Chemical gloves | 13361 (69) | 92 (72) | 208 (66) |
Data are presented as n (%) unless otherwise indicated. PPE: personal protective equipment. #: history of doctor-diagnosed eczema or hay fever; ¶: various PPE use is not mutually exclusive; individuals may report more than one method.