Proportion and number of cancer cases and deaths attributable to behavioral risk factors in Vietnam.

Identifying modifiable risk factors that contribute to cancer is essential in setting up preventive strategies. Therefore, this study aimed to estimate the number and proportion of cancer cases and deaths attributable to five behavior-related risk factors-tobacco smoking, second-hand smoking, alcohol consumption, high body mass index and insufficient physical activity in Vietnam in 2020. Population attributable fractions were calculated for relationships of risk factors and cancer types based on sufficient evidence according to IARC or strong evidence according to WCRF/AICR. Relative risks were retrieved from meta-analyses where possible. Prevalence of risk factors was obtained from the most current available nationally representative population surveys in Vietnam. Cancer cases and deaths were obtained from GLOBOCAN 2020. An estimated 40.5% of all cancer cases in men (39 924 cases) and 7.8% in women (6542 cases) were attributable to these risk factors. The proportions of cancer deaths attributable to these risk factors were 44.0% in men (32 807 cases) and 8.9% in women (4235 cases). Tobacco smoking was the leading cause of cancer cases and deaths in men, followed by alcohol consumption and high BMI. In women, high BMI accounted for the highest proportion of cancer cases and second-hand smoking accounted for the highest proportion of cancer deaths. Lung and upper aerodigestive tract cancer cases and deaths could have been reduced at least by half if these risk factors had been eliminated. To reduce cancer incidence and mortality, preventive actions focusing on tobacco control are likely to have the most significant impact, especially in men.