Table 3.
Self-reported occupational exposure of men to asbestos and HNSCC risk stratified by heavy smoking and/or heavy drinking status and by HPV16 serology. The RERI estimates (and corresponding 95% CIs) represent the magnitude and direction of departure from additivity between asbestos and the effect modifier.
| Primary Tumor Site | ||||||
|---|---|---|---|---|---|---|
| Oral Cavity | Pharynx | Larynx | ||||
| Asbestos Exposure by HNSCC Risk Factors | ncases/ncontrols | OR (95% CI) | ncases/ncontrols | OR (95% CI) | ncases/ncontrols | OR (95% CI) |
| Heavy smoking and/or drinkinga,b | ||||||
| Neither | ||||||
| Never occupationally exposed | 35/242 | Reference | 67/242 | Reference | 12/242 | Reference |
| Ever occupationally exposed | 8/65 | 0.78 (0.34–1.80) | 30/65 | 2.01 (1.09–3.71) | 2/65 | 0.59 (0.13–2.71) |
| Either | ||||||
| Never occupationally exposed | 87/275 | 2.30 (1.44–3.67) | 123/275 | 2.52 (1.64–3.87) | 48/275 | 3.24 (1.70–6.57) |
| Ever occupationally exposed | 30/97 | 1.87 (1.04–3.35) | 54/97 | 3.22 (1.89–5.47) | 22/97 | 4.02 (1.86–8.70) |
| RERI = −0.22 (−1.45, 1.02) | RERI = −0.31 (−2.08, 1.45) | RERI= 1.09 (−1.24, 3.43) | ||||
| HPV16 serologyc | ||||||
| Negative (L1, E6 and E7) | ||||||
| Never occupationally exposed | 101/480 | Reference | 93/480 | Reference | 51/480 | Reference |
| Ever occupationally exposed | 35/153 | 0.75 (0.47–1.18) | 49/153 | 1.45 (0.96–2.18) | 20/153 | 0.86 (0.48–1.57) |
| Positive (L1, E6 or E7) | ||||||
| Never occupationally exposed | 20/37 | 2.89 (1.54–5.40) | 37/97 | 16.73 (10.41–26.91) | 9/37 | 2.25 (0.96–5.25) |
| Ever occupationally exposed | 3/9 | 1.73 (0.43–6.97) | 35/9 | 22.21 (9.93–49.68) | 4/9 | 3.99 (1.03–15.41) |
| RERI = −0.90 (−3.87, 2.07) | RERI = 5.03 (−13.20, 23.25) | RERI = 1.89 (−3.68, 7.45) | ||||
Note Joint-effects models for the RERI calculations exclude subjects with any missing covariate data considered in the model. Variance-covariance matrices required for RERI calculations cannot be accurately estimated through multiple imputation in a computationally efficient manner.
Abbreviations HNSCC = head and neck squamous cell carcinoma; OR = odds ratio; CI: confidence interval
Adjusted for age, race, education, income, and HPV16 serostatus
Heavy smoker was defined as the 2nd and 3rd tertiles of pack-years among smokers (> 18.3 pack-years) and heavy drinker was defined as consumption of more than 14 alcoholic drinks per week
Adjusted for age, race, smoking, alcohol consumption, education, and income