Table 4 Distribution of pharyngeal cancer cases in the NCI-cohort by cumulative exposure to formaldehyde and study site (1934–2004)
Exposure (ppm-yr) | Plant 1 (Wallingford) | Plant 2–10 (all other plants) | ||||
|---|---|---|---|---|---|---|
Obs | Exp | SMR (95%CI) | Obs | Exp | SMR (95%CI) | |
0 | 0 | 0.77 | 0.00 (0.00–4.82) | 5 | 2.72 | 1.84 (0.60–4.29) |
(0, 0.5] | 6 | 2.21 | 2.71 (1.00–5.90) | 17 | 13.63 | 1.25 (0.73–2.00) |
(0.5, 5.5] | 6 | 2.85 | 2.10 (0.77–4.57) | 6 | 11.21 | 0.54 (0.20–1.17) |
> 5.5 | 5 | 1.83 | 2.73 (0.89–6.38) | 5 | 6.23 | 0.80 (0.26–1.87) |
Total | 17 | 7.66 | 2.22 (1.29–3.55) | 33 | 33.79 | 0.98 (0.67–1.37) |