Table 1.
Characteristics stratified by exposure to residential wood burning among participants from the Agricultural Lung Health Study (2009–2013).
| Characteristic | Total |
Unexposed |
Some exposure |
Frequent exposure |
|---|---|---|---|---|
| Gender | ||||
| Female | 1,372 (49%) | 1,098 (80%) | 123 (9.0%) | 151 (11%) |
| Male | 1,443 (51%) | 1,119 (78%) | 127 (8.8%) | 197 (14%) |
| Age | 63 ± 11 | 63 ± 11 | 63 ± 10 | 62 ± 11 |
| Height (cm) | 169 ± 10 | 169 ± 10 | 169 ± 9 | 169 ± 10 |
| Weight (kg) | 87 ± 20 | 87 ± 20 | 88 ± 20 | 86 ± 20 |
| Race/ethnicity | ||||
| White | 2,770 (98%) | 2,187 (79%) | 249 (9.0%) | 334 (12%) |
| Non-White | 45 (1.6%) | 30 (67%) | 1 (2.2%) | 14 (31%) |
| Education | ||||
| Up to high school graduate | 1,278 (45%) | 1,010 (79%) | 100 (7.8%) | 168 (13%) |
| More than high school | 761 (27%) | 608 (80%) | 62 (8.1%) | 91 (12%) |
| College graduate and above | 701 (25%) | 549 (78%) | 77 (11%) | 75 (11%) |
| Missing | 75 (2.7%) | 50 | 11 | 14 |
| State | ||||
| Iowa | 1,992 (71%) | 1,647 (83%) | 167 (8.4%) | 178 (8.9%) |
| North Carolina | 823 (29%) | 570 (69%) | 83 (10%) | 170 (21%) |
| Smoking status | ||||
| Never | 1,860 (66%) | 1,490 (80%) | 168 (9.0%) | 202 (11%) |
| Former | 832 (30%) | 639 (77%) | 74 (8.9%) | 119 (14%) |
| Current | 123 (4.4%) | 88 (72%) | 8 (6.5%) | 27 (22%) |
| Pack-years among ever smokers | 18 ± 21 | 18 ± 21 | 15 ± 18 | 18 ± 21 |
| Asthma status | ||||
| Noncase | 1,732 (62%) | 1,378 (80%) | 145 (8.4%) | 209 (12%) |
| Case | 1,083 (38%) | 839 (77%) | 105 (9.7%) | 139 (13%) |
| Atopy status | ||||
| Noncase | 2,206 (78%) | 1,749 (79%) | 196 (8.9%) | 261 (12%) |
| Case | 527 (19%) | 398 (76%) | 49 (9.3%) | 80 (15%) |
| Missing | 82 (2.9%) | 70 | 5 | 7 |
| Diagnosis of COPD and/or emphysema | ||||
| Noncase | 2,753 (98%) | 2,169 (79%) | 246 (8.9%) | 338 (12%) |
| Case | 59 (2.1%) | 46 (78%) | 4 (6.8%) | 9 (15%) |
| Missing | 3 (0.1%) | 2 | 0 | 1 |
| Season | ||||
| Spring (21 March–20 June) | 727 (26%) | 573 (79%) | 71 (9.8%) | 83 (11%) |
| Summer (21 June 21–20 September) | 824 (29%) | 648 (79%) | 69 (8.4%) | 107 (13%) |
| Fall (21 September–21 December) | 637 (23%) | 514 (81%) | 47 (7.4%) | 76 (12%) |
| Winter (22 December–20 March) | 627 (22%) | 482 (77%) | 63 (10%) | 82 (13%) |
Note: Statistics presented: (%) for categorical variables; unweighted mean ± (standard deviation) for continuous variables. Chi-square test of independence for categorical variables and Kruskal-Wallis test for continuous variables were performed to compare values across wood burning categories. -Values were for differences in exposure prevalence by race/ethnicity, smoking status, and state.