Risk factors associated with head and neck cancer in former smokers: A Brazilian multicentric study

Reduced tobacco consumption in the population has not been associated with reduced incidence rates of head and neck cancer in several countries.

To explore the associations between HNC and sociodemographic characteristics and lifestyle of former smokers from three Brazilian cancer centers.

A multicenter case-control study was conducted with 229 former smokers diagnosed with squamous cell carcinoma of the oral cavity, oropharynx, larynx, and 318 controls (former smokers without head and neck cancer). Bivariate and multiple logistic regression analyses were conducted to estimate odds ratios (ORs) with a 95% confidence interval (CI).

11-20 years after smoking cessation showed significant impact on HNC reduction (OR 0.22, 95% CI, 0.12-0.39), which reached 82% (95% CI, 0.09-0.35) among 20 + former smokers when compared to individuals who had stopped smoking for up to 5 years. A history of high-intensity smoking (>40 pack-years) increased HNC risk by 2.09 times (95% CI 1.13-3.89) when compared to subjects who smoked up to 20 pack-years. Past alcohol consumption (OR 1.99, 95% CI, 1.06-3.82) was also associated with head and neck cancer risk in former smokers when compared to no alcohol consumption. There was a decreased head and neck cancer risk in former smokers who had high school level of education (OR 0.38, 95% CI, 0.16-0.91) compared to illiterate former smokers; and former smokers with moderate intake of vegetables (OR 0.49, 95% CI, 0.28-0.85) and fruits (OR 0.43, 95% CI, 0.25-0.73) compared to those with low intake.

Head and neck cancer risk in former smokers decreases after 11 years after smoking cessation, former smokers with past alcohol consumption showed an increased risk of HNC. High school level of education and moderate intake of vegetables and fruits reduced HNC risk among former smokers.