Attributable cancer in Asia: A heterogeneous picture

Published estimates of cancer burden attributable to modifiable factors in Asia are not comparable due to heterogeneous methodologies. A comprehensive analysis is needed to characterize regional variations and inform prevention strategies. We estimated population attributable fractions (PAFs) for major avoidable cancer risk factors across Asian countries grouped into West Asia, South Asia, South-East Asia, Central Asia, and selected East Asian countries (China, Mongolia and North Korea; Japan and South Korea). Data sources included region-specific exposure estimates and established relative risks from international evaluations. Risk factors analyzed included tobacco use, alcohol consumption, infections, dietary factors, occupational factors, and excess body weight. PAFs were computed separately for individual risk factors and cancer types. Substantial heterogeneity was observed across Asia in the contribution of modifiable risk factors to cancer burden (table 1). Tobacco, infections, and alcohol were consistently among the leading contributors, although their ranking varied by region. Diet and excess body weight contributed substantially to several countries, with marked regional differences. Overall, PAFs for many risk factors were higher than those reported in Europe and the Americas. The distribution of cancer types with the highest attributable fractions differed across regions, reflecting variations in exposure patterns and baseline incidence. The burden of cancer attributable to modifiable factors in Asia is substantial yet highly heterogeneous across regions. Improving the availability and quality of exposure data is needed for more accurate assessments. Expansion of comparable, methodologically harmonized PAF estimation across additional Asian countries will strengthen regional cancer prevention strategies. Future work should incorporate temporal exposure trends and broaden the range of risk factors evaluated. Table 1. PAFs expressed as percentages, for major modifiable cancer risk factors referring to all cancers combined in Asia. Risk Factor Gender West Center South Southeast China+ North Korea+ Mongolia Japan+ South Korea All factors in the analysis Both 30.82 40.54 36.85 38.29 42.44 40.55 All factors in the analysis Male 35.95 48.15 43.25 47.09 55.89 45.87 All factors in the analysis Female 24.45 36.07 34.34 31.78 30.85 28.98 Diet * Both 8.55 12.07 6.14 9.78 11.12 7.93 Diet * Male 9.75 15.35 6.51 11.17 12.47 8.47 Diet * Female 6.54 8.99 5.6 8.08 9.34 6.45 Infection ** Both 8.66 18.43 14.11 16.32 15.13 14.11 Infection ** Male 8.14 15.24 7.19 13.72 15.71 13.74 Infection ** Female 8.01 19.91 20.24 17.53 13.77 11.43 BMI > 25 Both 6.2 6.29 2.63 2.46 3.38 5.5 BMI > 25 Male 3.73 4.05 1.48 1.64 3.71 5.35 BMI > 25 Female 8.01 7.72 3.5 2.8 3.01 4.75 Alcohol drinking Both 0.9 3.66 2.6 2.54 4.11 6.05 Alcohol drinking Male 1.54 7.16 5.59 5.04 7.54 8.63 Alcohol drinking Female 0.44 2.11 1.16 1.09 1.95 3.22 Tobacco smoking Both 11.03 7.42 11.21 12.83 17.25 15.77 Tobacco smoking Male 19.89 21.02 26.13 27.51 33.59 23.97 Tobacco smoking Female 4.04 1.91 3.76 5.03 6.61 7.2 *Including Low fruit and vegetable intake, high red and processed meat intake, dairy intake, fish intake **Including Helicobacter pylori, Hepatitis B virus, Hepatitis C virus, Human Papillomavirus virus