# Lung Cancer Risk Factors Beyond Smoking in Ethiopia: A Multicenter Matched Case–Control Study

## TL;DR

The study identifies multiple lung cancer risk factors in Ethiopia beyond smoking, highlighting the need for gender-specific prevention strategies.

## Contribution

The study reveals sex-specific and locally relevant risk factors for lung cancer in Ethiopia, beyond smoking.

## Key findings

- Lung cancer in Ethiopia is associated with low education, solid fuel use, and dietary patterns.
- Men are more exposed to smoking and occupational hazards, while women face higher exposure to secondhand smoke and processed food diets.
- Gender-sensitive public health strategies are needed to address these risk factors in Ethiopia.

## Abstract

In Ethiopia, smoking explains only a fraction of lung cancer cases, highlighting the importance of other local risk factors. This study examined 351 lung cancer patients and 702 matched hospital controls to uncover these drivers. Beyond smoking, lung cancer was independently associated with low education and wealth, use of solid fuels, occupational exposures, limited physical activity, processed food- and meat-based dietary patterns, secondhand smoke, prior tuberculosis, and family history of cancer. While both men and women were affected by these risks, men were more exposed to smoking, occupational hazards, meat-based diets, and family history. In contrast, women faced greater exposure to secondhand smoke, solid fuels, and processed food diets. These findings underscore the need for gender-sensitive public health strategies that address multiple local risk factors to improve lung cancer prevention and early detection in resource-limited settings like Ethiopia.

Background: While smoking is the dominant global driver of lung cancer, less than a quarter of Ethiopian patients have ever smoked, pointing to locally relevant risk factors. Evidence to guide prevention and early detection in resource-limited settings is scanty. Methods: To address this gap, we conducted a multicenter matched case–control study including 351 histopathologically confirmed primary lung cancer cases and 702 hospital-based controls matched by sex, age (±5 years), and residence. Directed acyclic graphs informed the selection of variables, and multivariable hierarchical conditional logistic regression was used to identify risk factors beyond smoking. Results: The analysis shows that lung cancer was independently associated with low education, wealth, solid-fuel use, occupational exposure, insufficient physical activity, meat-based and processed food dietary patterns, secondhand smoke (SHS), prior tuberculosis, and family history of cancer. Subgroup analysis by sex revealed consistent associations across males and females, but exposure distributions explained sex-specific patterns: smoking, occupational exposure, meat-based diets, and family history were more common among males, whereas SHS, the use of solid fuels, and processed food dietary patterns predominated in females. Conclusions: Lung cancer in Ethiopia appears to be associated with several factors in addition to smoking. Gender-sensitive public health interventions targeting these locally relevant risk factors are essential for effective prevention and early detection.