Table 4.
Associations of BTEX-H, burning/flaring oil/gas, PM2.5 with incident asthma among GuLF Study workers (N=19,018)
| Exposure | Asthma cases n (%) | Risk RatioCRUDE (95% CI) | Risk RatioMODEL1 (95% CI) | Risk RatioMODEL2 (95% CI)a |
|---|---|---|---|---|
| Benzene (ppb-days) | ||||
| Quartile 1 | 129(13) | Referent | Referent | Referent |
| Quartile 2 | 231 (24) | 1.79(1.45,2.21) | 1.60(1.30,1.98) | 1.60(1.30,1.98) |
| Quartile 3 | 267(27) | 2.07(1.68,2.54) | 1.97(1.60,2.40) | 1.91(1.55,2.35) |
| Quartile 4 | 356(36) | 2.76(2.26,3.36) | 2.71(2.22,3.32) | 2.67(2.17,3.28) |
| p-trend <0.0001 | ||||
| Toluene (ppb-days) | ||||
| Quartile 1 | 130(13) | Referent | Referent | Referent |
| Quartile 2 | 214(22) | 1.65(1.33,2.04) | 1.50(1.22,1.85) | 1.49(1.21,1.84) |
| Quartile 3 | 248(25) | 1.91(1.55, 2.35) | 1.86(1.51,2.29) | 1.80(1.46,2.23) |
| Quartile 4 | 391(40) | 3.01(2.48,3.65) | 3.01(2.47,3.68) | 2.99(2.44,3.66) |
| p-trend <0.0001 | ||||
| Ethylbenzene (ppb-days) | ||||
| Quartile 1 | 132(13) | Referent | Referent | Referent |
| Quartile 2 | 225(23) | 1.70(1.38,2.10) | 1.53(1.24,1.89) | 1.55(1.26,1.91) |
| Quartile 3 | 279(28) | 2.11(1.72,2.59) | 1.91(1.56,2.34) | 1.91(1.56,2.34) |
| Quartile 4 | 347(35) | 2.63(2.16,3.20) | 2.69(2.20,3.28) | 2.66(2.16,3.27) |
| p-trend <0.0001 | ||||
| Xylenes (ppb-days) | ||||
| Quartile 1 | 151(15) | Referent | Referent | Referent |
| Quartile 2 | 194(20) | 1.28(1.04,1.58) | 1.24(1.01,1.51) | 1.25(1.02,1.53) |
| Quartile 3 | 252(26) | 1.67(1.37,2.03) | 1.56(1.29,1.90) | 1.56(1.28,1.90) |
| Quartile 4 | 386(39) | 2.56(2.13,3.07) | 2.62(2.18,3.15) | 2.62(2.16,3.17) |
| p-trend <0.0001 | ||||
| n-Hexane (ppb-days) | ||||
| Quartile 1 | 125(13) | Referent | Referent | Referent |
| Quartile 2 | 248(25) | 1.98(1.61,2.45) | 1.66(1.34,2.05) | 1.66(1.34,2.05) |
| Quartile 3 | 272(27) | 2.18(1.77,2.68) | 2.08(1.69,2.56) | 2.08(1.69,2.56) |
| Quartile 4 | 338(34) | 2.70(2.21,3.31) | 2.79(2.27,3.43) | 2.71 (2.19,3.37) |
| p-trend <0.0001 | ||||
| Potential exposure to burning oil/gas (ordinal categories) | ||||
| No | 822(83) | Referent | Referent | Referent |
| Low/Medium | 123(13) | 1.62(1.35,1.95) | 1.48(1.25,1.77) | 1.08(0.90,1.29) |
| High | 21(2) | 2.22(1.47,3.35) | 1.67(1.16,2.40) | 1.36(0.94,1.96) |
| PM2.5 (μg/m3) | ||||
| Non-water workers | 546(56) | 1.12(.98,1.29) | 0.87(0.76,1.00) | 1.18(1.02,1.37) |
| Low-exposed water workers and In situ (10 μg/m3) | 306(31) | Referent | Referent | Referent |
| Source (29 μg/m3) and Hot zone (97 μg/m3) | 131(13) | 1.73(1.41,2.13) | 1.37(1.12,1.68) | 1.16(0.95,1.42) |
a
Models with ordinal burning/flaring oil/gas are missing N=389 participants due to lack of information on this exposure
Model 1: age, gender, race, ethnicity, smoking, pack-years, previous oil spill cleanup work, previous oil industry experience, highest educational attainment
Model 2: Model 1+ potential exposure to burning/flaring crude oil for THC analyses (or THC for ordinal categories of burning/PM2.5 analyses)