Table 3.
Cancer risks from formaldehyde exposures were reviewed on the basis of the three largest and recently updated cohorts
| Study | NCI cohorta (<1996–1994) | NCI cohorta (<1996–2004) | UK cohort (1941–2000)a | US garment worker cohort (1955–1998)a | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Exposure (ppm) | Median average intensity: 0.45 and range: 0.01–4.25. Exposure to ≥2 occurred in 4.7% and 22.6% had peak exposures at ≥4 | Range: 0.1 to >2 | Geometric mean: 0.15 and geometric standard deviation 1.90. Range 0.09–0.2. Past exposures may have been substantially higher | |||||||||
| Risk estimateb | ICD-8c | O/E | SMR | ICD-8c | O/E | SMR | ICD-9c | O/E | SMR | ICD-9c | O/E | SMR |
| All cancers | 140–209 | 1916d/–e | 0.90* | – | – | 1.07* | 140–208 | 1511/1375.2 | 1.10* | 140–208 | 608/– | 0.89* |
| Nose and nasal sinuses | 160 | 3/– | 1.19 | – | – | – | 160 | 2/2.3 | 0.87 | 160 | 0/0.16 | – |
| Pharynx | – | – | – | 146–149.1 | 15/9.7 | 1.55 | 146–149 | 3/– | 0.64 | |||
| Nasopharynx | 147 | 8f/– | 2.10* | 147 | 1/2 | – | 147 | 0/0.96 | – | |||
| Larynx | 161 | 23/– | 0.95 | – | – | – | 161 | 14/13.1 | 1.07 | 161 | 3/– | 0.88 |
| Lung | 162 | 641/– | 0.97 | – | – | – | 162 | 594/486.8 | 1.22* | 162 | 147/– | 0.98 |
| Bone | 170 | 7/– | 1.57 | – | – | – | 170 | 6/3.5 | 1.73 | – | ||
| Prostate | 185 | 131/– | 0.90 | – | – | – | 185 | 80/99.4 | 0.80 | 185 | 11/– | 1.58 |
| Hodgkin’s disease | 201 | 20/– | 1.26 | 201 | 25/– | 1.42 | 201 | 6/8.5 | 0.70 | 201 | 2/– | 0.55 |
| Non-Hodgkin’s lymphoma | 200 | 44/– | 0.61* | 200 | 94/– | 0.85 | 200 | 31/31.7 | 0.98 | 200 | 5/– | 0.85 |
| &202 | &202 | &202.0 | ||||||||||
| &202.1 | ||||||||||||
| &202.8 | ||||||||||||
| Multiple myelomas | 203 | 28/– | 0.88 | 203 | 48/– | 0.94 | 203.0 | 15/17.5 | 0.86 | – | ||
| Leukemia | 204–207 | 65/– | 0.85 | 204–207 | 116/– | 1.02 | 204–208 | 31/34.1 | 0.91 | 204–208 | 24/– | 1.09 |
| Lymphatic leukemia | – | – | – | 204 | 36/– | 1.15 | – | – | – | – | – | – |
| Myeloid leukemia | 205 | –/– | – | 205 | 44/– | 0.90 | 0.89g | 205 | 15/– | 1.44 | ||
| Stomach | – | – | – | – | – | – | 151 | 150/114.4 | 1.31* | 151 | 13/– | 0.80 |
| All digestive | 150–159 | 420/– | 0.89* | – | – | – | – | – | – | 150–159 | 116/– | 0.77* |
The US National Cancer Institute (NCI) cohort comprised 25,619 workers employed in ten US formaldehyde producing or using facilities. Workers were employed prior to 1 January 1966 and were followed-up through 31 December 1994 (Hauptmann et al. 2003; Hauptmann et al. 2004) and recently through 31 December 2004 for lymphohematopoietic malignancies (Freeman et al. 2009). A British (UK) cohort from six British factories, comprising 14,014 men employed after 1937 and followed-up through December 2000 (Coggon et al. 2003). The US National Institute for Occupational Safety and Health established a cohort with 11,039 employees in three garment facilities (US garment worker cohort). The study was updated through 31 December 1998 (Pinkerton et al. 2004)
aComparison with national death rates
bStandardized mortality ratio (SMR), observed cases (O), expected cases (E), and the ratio (O/E). When the 95% CI does not include 1.00, it is indicated by * and bold
cInternational Classification of Diseases: 8th revision (ICD-8) and 9th revision (ICD-9)
dIn the Hauptmann et al. (2003) study, the number of formaldehyde workers who had died was 1,916 (2-year lag interval) and in the Hauptmann et al. (2004), the number was 1,723 (15-year lag interval). The lag interval was 2 years in the Freeman et al. (2009) study
eNot indicated
fHauptmann et al. 2004 (Table 2) report eight nasopharyngeal cancers among formaldehyde exposed workers that were used for the SMR calculation. Although one subject was misclassified on the death certificate, this subject was retained in the SMR calculation since population reference rates are based on death certificates. Also, the exact 95% CI was reported to be 0.91–4.14 and thus the SMR value of 2.10 is not statistically significant. The seven cases in the text and in Tables 3–6 of Hauptmann et al. (2004) were used for calculation of relative risks
gEstimated by Cole and Axten (2004) for the high exposed group (>2 ppm)