Childhood passive smoke exposure is associated with adult head and neck cancer

Introduction: Passive smoke is carcinogenic but its association with head and neck squamous cell carcinoma (HNSCC) is uncertain. Methods: We conducted a case-control study of childhood passive smoke exposure (CPSE) and HNSCC in 858 cases and 806 frequency-matched controls using an interviewer-administered questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression controlling for adult smoking in the total study population, and in never-smokers only (184 cases and 415 controls). CPSE was also studied in oropharyngeal separately from other HNSCC using polytomous logistic regression. Results: CPSE was associated with HNSCC (OR, 1.28; 95% CI, 1.01–1.63) after controlling for adult smoking and other factors. This association was similar in magnitude, although not statistically significant, among subjects who never smoked as adults (OR, 1.19, 95% CI, 0.80–1.76). CPSE was associated more strongly with oropharyngeal cancer (a HNSCC subtype commonly associated with human papillomavirus (HPV) infection) than with HNSCC at non-oropharyngeal sites (OR, 2.02; 95% CI, 1.01–4.06, N = 52 cases vs. OR, 1.04; 95% CI, 0.68–1.60, N = 132 cases; P-for-heterogeneity = 0.08). Conclusions: Data from this large US-based case control study suggest a role for CPSE in HNSCC etiology.