In 2019, smoking was associated with 142,931 deaths from colorectal cancer, high with 85,882 deaths, and alcohol use with 52,495 deaths, according to findings. These factors accounted for approximately one-third of all colorectal cancer-related deaths globally and remain key contributors to mortality, particularly in regions with low and middle sociodemographic index levels.
Researchers from the University of South China analyzed data from the Global Burden of Disease 2019 study, which includes health information from 204 countries. They examined age-standardized mortality rates (ASMRs) for colorectal cancer (CRC) across Socio-Demographic Index (SDI) quintiles, which categorize countries by income per capita, educational attainment, and fertility rate into high, upper-middle, middle, lower-middle, and low SDI groups.
From 1990 to 2019, the global ASMR for CRC attributable to smoking decreased by 16.00%, from 2.11 to 1.77 per 100,000 individuals. In high-SDI countries, the decline was more pronounced at 39.27%, from 3.71 to 2.25 per 100,000. In contrast, the ASMR for CRC attributable to high body mass index (BMI) increased by 23.25% over the same period, rising from 0.86 to 1.07 per 100,000.
The study also highlighted significant sex-based differences. In 2019, men had substantially higher ASMRs than women for all three risk factors. For smoking-related CRC, the ASMR was 67.49 per 100,000 in men compared with 13.40 per 100,000 in women. Similar disparities were observed for alcohol use (49.40 vs 10.74 per 100,000) and high BMI (39.40 vs 10.97 per 100,000).
Age-specific analysis showed that individuals aged 70 to 74 years had the highest mortality rates. In this age group, the global age-specific rate for smoking-attributable CRC mortality was 14,086.8 per 1,000,000 population.
Trends in mortality varied by development level. In high-SDI countries, including the U.S. and Italy, CRC deaths attributable to smoking and alcohol use have declined, likely reflecting increased access to screening, early detection programs, and more effective treatment. In countries with lower SDI levels, including India, China, and Tanzania, these mortality rates are projected to rise through 2030.
Using a Bayesian age–period–cohort model, the researchers projected that the global ASMR for alcohol-attributable CRC in men will increase by 8.88% between 2020 and 2030. A smaller increase of 1.43% is expected among women. Smoking-related CRC mortality is projected to decline slightly in both sexes during this period.
The study also identified a rising burden of early-onset CRC (diagnosed before age 50), particularly in association with high BMI and physical inactivity.
To reduce the global burden of CRC, the authors recommended strengthening health education, expanding access to screening, and implementing prevention programs focused on smoking cessation and alcohol moderation.
“ASMRs associated with alcohol consumption, smoking, and high BMI in men showed increasing trends in low, lower-middle, and middle SDI regions,” according to findings published in Frontiers in Oncology.
These findings may inform targeted public health strategies aimed at prevention and early detection of CRC, particularly in resource-limited settings.
The authors reported no conflicts of interest.
