Table 4.
Occupational and demographic predictors of mortality in South African ex-miners who left the industry 2001–2013 (N = 306,297)a
| Characteristic | Unadjusted hazard Ratio | Adjusted hazard ratio | 95% confidence interval (adjusted) |
|---|---|---|---|
| Gender | |||
| Female | 1.00 | 1.00 | – |
| Male | 2.36 | 1.57 | 1.45–1.71 |
| Racial ascription | |||
| White | 1.00 | 1.00 | – |
| Black | 3.25 | 3.30 | 3.15–3.46 |
| Coloured | 1.64 | 1.84 | 1.60–2.12 |
| Indian | 1.00 | 1.33 | 0.86–2.07 |
| Unknown | 0.65 | 0.30 | 0.04–2.10 |
| Age at exit (years) | |||
| 15–24.9 | 1.00 | 1.00 | – |
| 25–34.9 | 2.12 | 1.91 | 1.81–2.01 |
| 35–44.9 | 3.54 | 2.77 | 2.63–2.92 |
| 45–54.9 | 3.39 | 2.98 | 2.82–3.15 |
| 55–64.9 | 2.94 | 2.85 | 2.68–3.03 |
| ≥ 65 | 2.71 | 3.08 | 2.48–3.84 |
| Calendar year of exit | |||
| 2001–2004 | 1.00 | 1.00 | – |
| 2005–2009 | 0.75 | 0.77 | 0.75–0.79 |
| 2010–2013 | 0.44 | 0.45 | 0.43–0.46 |
| Occupational category | |||
| Surface only | 1.00 | 1.00 | – |
| Underground only | 1.37 | 1.21 | 1.17–1.25 |
| Underground and surface | 2.24 | 1.33 | 1.28–1.39 |
| Commodity | |||
| Platinum only | 1.00 | 1.00 | – |
| Gold only | 1.35 | 1.15 | 1.12–1.19 |
| Coal only | 0.35 | 0.42 | 0.36–0.49 |
| Multiple sectors | 1.65 | 1.15 | 1.11–1.19 |
| Other only | 0.49 | 0.66 | 0.56–0.77 |
| Unknown only | 0.63 | 0.83 | 0.79–0.88 |
| Time in employment (years) | |||
| 0–4.9 | 1.00 | 1.00 | – |
| 5–9.9 | 1.83 | 1.24 | 1.20–1.29 |
| 10–14.9 | 2.14 | 1.20 | 1.16–1.24 |
| 15–19.9 | 1.95 | 1.06 | 1.02–1.11 |
| 20–24.9 | 1.35 | 0.83 | 0.76–0.89 |
| ≥ 25 | 1.25 | 0.83 | 0.74–0.92 |
aCox Proportional Hazards model: adjustment for all variables in table