The association between OAAS and potential individual risk factors
| Variable studied | Crude odds ratios (95% CI) | Adjusted odds ratios* (95% CI) | Alternative adjusted odds ratios† (95% CI) |
|---|---|---|---|
| *Adjusted for exposure index, current and ex smoking at employment, and Maori/Samoan ethnicity. | |||
| †Adjusted for exposure grade, current and ex smoking at employment, and Maori/Samoan ethnicity. | |||
| Hay fever (at employment) | 1.65 (0.59 to 4.60) | 2.28 (0.76 to 6.89) | 2.66 (0.84 to 8.42) |
| All hay fever | 2.91 (1.35 to 6.26) | 3.58 (1.57 to 8.21) | 3.32 (1.37 to 8.05) |
| Family history of asthma (at employment) | |||
| Family history of asthma | 1.60 (0.58 to 4.42) | 1.63 (0.57 to 4.69) | 2.23 (0.71 to 7.03) |
| First degree family history | 1.73 (0.61 to 4.89) | 1.80 (0.61 to 5.33) | 2.25 (0.71 to 7.10) |
| Numbers of family members | 1.59 (0.80 to 3.13) | 1.60 (0.79 to 3.21) | 1.99 (0.91 to 4.34) |
| Family history of asthma (at employment and subsequently) | |||
| Family history of asthma | 1.29 (0.60 to 2.79) | 1.44 (0.64 to 3.24) | 1.28 (0.55 to 2.97) |
| First degree family history | 1.40 (0.64 to 3.07) | 1.60 (0.69 to 3.68) | 1.37 (0.58 to 3.25) |
| Numbers of family members | 1.21 (0.60 to 2.43) | 1.26 (0.61 to 2.61) | 1.07 (0.51 to 2.24) |
| A history of hay fever and familial asthma | 1.54 (0.71 to 3.35) | 1.94 (0.85 to 4.43) | 2.42 (0.99 to 5.93) |
| Tobacco smoking | |||
| Never smoker | reference | reference | reference |
| Ex-smoker at employment | 0.81 (0.25 to 2.64) | 0.70 (0.21 to 2.35) | 0.83 (0.24 to 2.84) |
| Smoking at start of employment | 1.31 (0.64 to 2.69) | 1.29 (0.61 to 2.75) | 1.46 (0.66 to 2.84) |
| Light smoker | 0.47 (0.06 to 3.98) | 0.43 (0.05 to 3.72) | 0.60 (0.07 to 5.14) |
| Moderate smoker | 1.62 (0.78 to 3.38) | 1.49 (0.68 to 3.26) | 1.82 (0.82 to 4.03) |
| Heavy smoker | 1.11 (0.37 to 3.40) | 1.64 (0.50 to 5.43) | 1.23 (0.39 to 4.01) |
| Smoking at termination of employment or diagnosis | 1.52 (0.77 to 3.00) | 1.70 (0.84 to 3.42) | 1.72 (0.85 to 3.51) |
| History of bronchitis | 4.00 (0.25 to 63.95) | 3.68 (0.20 to 66.49) | 5.87 (0.31 to 112.00) |
| History of childhood asthma | 2.00 (0.18 to 22.06) | 3.02 (0.26 to 34.86) | 11.61 (0.63 to 213.84) |
| History of dermatitis | 1.21 (0.32 to 4.52) | 1.96 (0.49 to 7.84) | 1.79 (0.43 to 7.55) |
| Maori/Samoan ethnicity | 1.48 (0.50 to 4.34) | 1.42 (0.46 to 4.45) | 1.18 (0.38 to 3.63) |
| Wheeze on auscultation at pre-employment examination | 4.00 (0.56 to 28.40) | 4.81 (0.65 to 35.44) | 6.55 (0.56 to 77.10) |
| Being overweight (BMI 25.0–29.9) | 1.13 (0.56 to 2.31) | 1.10 (0.52 to 2.36) | 1.41 (0.60 to 3.28) |
| Being obese (BMI ⩾30.0) | 2.09 (0.71 to 6.16) | 2.17 (0.68 to 6.87) | 2.82 (0.79 to 10.04) |
| Spirometric variables | |||
| FVC (% of predicted) | 1.01 (0.97 to 1.04) | 1.01 (0.98 to 1.05) | 1.00 (0.96 to 1.04) |
| FEV1 (% of predicted) | 0.98 (0.95 to 1.01) | 0.99 (0.96 to 1.02) | 0.98 (0.95 to 1.01) |
| FER (FEV1/FVC %) | 0.93 (0.88 to 0.98) | 0.93 (0.88 to 0.99) | 0.93 (0.88 to 0.99) |
| Stratified analysis | |||
| FER ⩾80.0% | reference | reference | reference |
| FER 75.0–79.9% | 2.22 (1.05 to 4.72) | 2.05 (0.93 to 4.52) | 3.07 (1.26 to 7.50) |
| FER 70.0–74.9% | 3.35 (1.15 to 9.75) | 2.62 (0.85 to 8.07) | 3.46 (1.01 to 11.89) |
| FER <70.0% | 2.04 (0.20 to 20.56) | 2.09 (0.20 to 21.68) | 2.94 (0.24 to 36.46) |