Figure 2.

Hazard ratios (HRs) of head and neck cancer, and corresponding confidence intervals (95% CIs), according to alcohol drinking intensity (g per day) and food folate intake (μg per day). The HRs were derived from Cox proportional hazard models, adjusting for age, sex, body mass index, education, race/ethnicity, pipe smoking status, cigar smoking status, pack-year cigarette smoking, alcohol drinking intensity, non-alcohol total energy, total vegetable and fruit intake. The number of cases and controls within each category was indicated below the corresponding HR as: ‘number of cases: number of cohorts’. We found no interaction between drinking, and food folate intake on HNC risk.