# The association of tobacco use on gastrointestinal cancers: A secondary dataset analysis of the Global Burden of Disease Study 2021 and Mendelian randomization

## TL;DR

This study examines how tobacco use affects gastrointestinal cancers globally from 1990 to 2021, finding a decline in disease burden but persistent regional and demographic disparities.

## Contribution

The study combines GBD data analysis and Mendelian randomization to assess tobacco's impact on gastrointestinal cancers, revealing regional trends and the lack of genetic evidence for a causal link.

## Key findings

- Esophageal cancer had the highest burden in 2021 with a mortality rate of 2.54 deaths per 100,000 population.
- Stomach cancer mortality decreased significantly from 2.81 to 1.25 deaths per 100,000 population between 1990 and 2021.
- Mendelian randomization found no genetic evidence supporting an association between tobacco use and gastrointestinal cancers.

## Abstract

Gastrointestinal cancers remain a major global health issue, with tobacco use as a key factor. Understanding the impact of tobacco use on these cancers and its regional trends is essential for effective prevention strategies.

Using data from the Global Burden of Disease (GBD) study, we analyzed mortality and disability-adjusted life years (DALYs) related to tobacco from 1990 to 2021. Joinpoint regression estimated average annual percent change (AAPC), and ARIMA predicted disease burden up to 2036. Two-sample Mendelian randomization (MR) analysis with GWAS data, applied methods such as inverse variance weighting (IVW) and MR-Egger for causal inference.

Esophageal cancer had the highest burden in 2021, with a mortality rate of 2.54 deaths per 100000 population and a DALY rate of 58.49 DALYs per 100000 population. Stomach cancer showed the most significant decrease, with mortality dropping from 2.81 to 1.25 deaths per 100000 population (AAPC= -2.58; 95% uncertainty interval, UI: -2.61– -2.55) and DALY rates decreasing from 71.71 to 29.01 DALYs per 100000 population (AAPC= -2.87; 95% UI: -2.90 – -2.84). The disease burden was higher in older males. ARIMA analysis showed a general decline in disease burden, though some regions had an increasing trend. MR analysis did not provide genetic evidence supporting an association between tobacco use and these cancers.

From 1990 to 2021, the global burden of gastrointestinal cancers linked to tobacco use showed a declining trend. However, mortality and DALY rates remain high, with significant regional, age, and gender differences, highlighting the need for continued tobacco control efforts.