Follow up survey of automotive stamping plant and engine plant workers, Detroit, MI, USA, 1993–94; population examined at follow up, as a proportion of eligible baseline subjects, by baseline exposure level*
| Exposure level | Baseline (n) | No. (%) examined at follow up |
|---|---|---|
| *p value = 0.19 from χ2 statistic on 3 d.o.f., test of difference in proportions among non-missing exposure levels. | ||
| Missing | 127 | 76 (60%) |
| Very low (0–6) | 116 | 76 (66%) |
| Low (7–12) | 344 | 251 (73%) |
| Moderate (13–18) | 468 | 336 (72%) |
| High (19–25) | 125 | 61 (65%) |
| Total | 1180 | 820 (69%) |