Outcomes from secondary screening: silicosis diagnosis status by participant demographic and occupational exposure characteristics
| Silicosis diagnosis | Comparison between groups | |||||
| No silicosis | Confirmed silicosis | Unadjusted analyses | Adjusted analyses* | |||
| N=297 | N=117 | OR (95% CI) | P value | OR (95% CI) | P value | |
| Sex, n (column %) | ||||||
| Male | 284 (95.6) | 117 (100) | Ref | |||
| Female | 13 (4.4) | 0 (0.0) | --- | 0.024 | --- | |
| Age (years), median (P25–P75) | 36.1 (28.9–45.1) | 42.1 (34.8–49.7) | 1.04 (1.02 to 1.06) | <0.001 | 1.04 (1.01 to 1.06) | 0.001 |
| BMI (kg/m2)†, mean (SD) | 28.2 (5.8) | 26.5 (4.5) | 0.94 (0.90 to 0.98) | 0.007 | 0.94 (0.90 to 0.99) | 0.012 |
| Smoking history, n (column %) | ||||||
| Never | 126 (42.4) | 29 (24.8) | Ref | Ref | ||
| Former/current | 171 (57.6) | 88 (75.2) | 2.24 (1.39 to 3.61) | 0.001 | 2.17 (1.32 to 3.56) | 0.002 |
| Pack years†, median (P25–P75) | ||||||
| All | 0.4 (0.0–7.1) | 7.5 (0.0–13.8) | 1.07 (1.04 to 1.09) | <0.001 | 1.07 (1.04 to 1.10) | <0.001 |
| Former/current smokers only | 6.5 (2.4–11.4) | 11.0 (6.1–20.2) | 1.06 (1.03 to 1.09) | <0.001 | 1.06 (1.02 to 1.10) | 0.004 |
| Country of birth, n (column %) | ||||||
| Australia | 164 (56.5) | 48 (42.1) | Ref | Ref | ||
| Other (not Australia) | 126 (43.5) | 66 (57.9) | 1.79 (1.15 to 2.77) | 0.009 | 1.37 (0.86 to 2.20) | 0.190 |
| Rose dyspnoea score, n (column %) | ||||||
| 0 | 208 (70.3) | 71 (60.7) | Ref | Ref | ||
| 1 | 62 (20.1) | 22 (18.8) | 1.04 (0.60 to 1.81) | 0.891 | 1.15 (0.63 to 2.09) | 0.643 |
| 2 | 18 (6.1) | 12 (10.3) | 1.95 (0.90 to 4.25) | 0.092 | 2.65 (1.10 to 6.38) | 0.030 |
| 3 | 8 (2.7) | 12 (10.3) | 4.39 (1.73 to 11.19) | 0.002 | 4.69 (1.60 to 13.78) | 0.005 |
| SBI exposures | ||||||
| SBI career duration, years | ||||||
| Median (P25–P75) | 8 (5–14) | 12 (9–21) | 1.07 (1.04 to 1.09) | <0.001 | 1.08 (1.04 to 1.12) | <0.001 |
| Range | <1–44 | 3–43 | ||||
| Age at first SBI job, years | ||||||
| Median (P25–P75) | 25 (20–33) | 25 (20–33) | 1.00 (0.98 to 1.03) | 0.923 | 0.99 (0.96 to 1.01) | 0.289 |
| Range | 15–59 | 13–58 | ||||
| No of SBI jobs held, n | ||||||
| Median (P25–P75) | 2 (1–3) | 3 (2–4) | 1.32 (1.17 to 1.48) | <0.001 | 1.19 (1.04 to 1.37) | 0.014 |
| Range | 1–9 | 1–30 | ||||
| Highest dry processing exposure intensity from both personal and bystander exposure, n (column %) | ||||||
| Never | 15 (5.1) | 2 (1.7) | Ref | Ref | ||
| Rarely 1%–9% | 19 (6.4) | 4 (3.4) | 1.58 (0.25 to 9.82) | 0.624 | 1.24 (0.18 to 8.47) | 0.827 |
| Sometimes 10%–24% | 41 (13.8) | 14 (12.0) | 2.56 (0.52 to 12.62) | 0.248 | 2.59 (0.49 to 13.65) | 0.261 |
| Frequently 25%–49% | 53 (17.8) | 13 (11.1) | 1.84 (0.37 to 9.07) | 0.454 | 1.63 (0.31 to 8.65) | 0.565 |
| Very frequently 50%–99% | 101 (34.0) | 43 (36.7) | 3.19 (0.70 to 14.57) | 0.134 | 2.94 (0.60 to 14.32) | 0.183 |
| Always 100% | 68 (22.9) | 41 (35.1) | 4.52 (0.98 to 20.79) | 0.053 | 3.89 (0.78 to 19.38) | 0.097 |
| Estimated silica exposure category, n (column %) | ||||||
| Low/medium | 40 (13.5) | 5 (4.3) | Ref | Ref | ||
| High/very high | 257 (86.5) | 112 (95.7) | 3.49 (1.34 to 9.07) | 0.010 | 4.46 (1.65 to 12.07) | 0.003 |
*Factors adjusted for include age, BMI, smoking status and country of birth. Age and BMI were highly correlated therefore BMI centred at the mean was used in the regression models. Age at first exposure was highly correlated with age, therefore, in the adjusted model assessing the relationship between age at first SBI job and silicosis diagnosis, age was excluded. Highest exposure was additionally adjusted for career duration. Number of SBI jobs held was additionally adjusted for career duration.
†BMI data missing for 5; number of cigarettes missing for 46.
BMI, body mass index; col, column; P25, 25th percentile; P75, 75th percentile; SBI, stone benchtop industry.