An unexpected paradox: examining the relationship between solid fuel heating and reduced cancer risk in CHARLS

Sep 22, 2026

Aim While solid fuel use is a known health concern, its specific link to cancer incidence via heating in China’s elderly remains unclear. This study investigated this association using data from the China Health and Retirement Longitudinal Study (CHARLS). Methods The research analyzed CHARLS data, treating solid fuels for heating as the exposure and incident cancer as the outcome, using logistic regression with confounder adjustment. Results Over nine years, 299 of 6,753 participants developed cancer, and solid fuel heating showed a lower cancer risk; mediation and subgroup analyses explored mechanisms and heterogeneity. Conclusion The findings indicate a paradoxical statistical association, cautioning against causal interpretation and emphasizing structural bias, including access, socioeconomic status, and detection effects.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages13

Reading Time33 min

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Abstract

Aim

Methods

Results

Conclusion

Introduction

Global cancer burden and need for evidence

Solid fuel use and indoor air pollution

Prior epidemiological evidence and research gaps

Wang et al. BMC Cancer (2026) 26:703 BMC Cancer [https://doi.org/10.1186/s12885-026-16011-4](https://doi.org/10.1186/s12885-026-16011-4) RESEARCH Open Access An unexpected paradox: examining the relationship between solid fuel heating and reduced cancer risk in CHARLS Xinlin Wang 1*, Linghao Xu2 and XikunYang3 Abstract Aim While solid fuel use is a known health concern, its specific link to cancer incidence via heating in China’s elderly remains unclear. This study investigated this association using data from the China Health and Retirement Longitudinal Study (CHARLS) . Methods The research used data from CHARLS. The primary exposure variable was the use of solid fuels for heating. The primary outcome was incident cancer. All statistical analyses were performed utilizing SPSS software (version 25. 0) and R software (version 4 .4.4) . Results We analyzed 6,753 participants without baseline cancer. The primary exposure was solid fuel use for heating, and the outcome was incident cancer. Logistic regression models were used, adjusting for confounders. Over a nine-year follow-up, 299 (4 .43%) participants developed cancer. Contrary to the initial hypothesis, solid fuel use for heating was statistically associated with a lower cancer risk (adjusted OR = 0 . 77, 95% CI: 0 .61–0. 98) . Mediation analysis indicated depressive symptoms, LDL-C, and total cholesterol masked portions ofthis effect. Subgroup analyses showed the association was more pronounced in specific demographics. Conclusion This study reveals a paradoxical statistical link between solid fuel heating and reduced cancer risk. We strongly caution against interpreting this as a biological causal effect. Instead, methodological factors and sociodemographic biases—such as healthcare access, socioeconomic status, and detection bias—are likely critical contributors. These findings highlight the importance of accounting for structural biases in health research to avoid misleading conclusions. Keywords Solid Fuel, heating, Cancer, Risk, CHARLS *Correspondence: Xinlin Wang [837775318@qq.com](837775318@qq.com) Full list of author information is available at the end of the article © The Author(s) 2026. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creati](http://creati)[vecommons.org/l](vecommons.org/l)icenses/by-nc-nd/4.0/. Wang et al. BMC Cancer (2026) 26:703 Page 2 of 13 Graphical abstract Introduction Cancer represents the second leading cause of death globally, with its burden projected to increase substantially over the next two decades [1]. According to the 2021 Global Burden of Disease (GBD) data, cancerrelated deaths accounted for 14.57% of total mortality in both sexes worldwide [2]. As life expectancy rises, so does the lifetime risk of developing cancer. In China, 4,568,754 new cancer cases and 3,002,899 cancer-related deaths were reported in 2020, with the growing burden largely attributable to population aging and unhealthy lifestyle factors [3]. It is therefore imperative to analyze a wide range of epidemiological d

FAQs

What is the main research question of the study?

The study examines how solid fuel use for heating relates to incident cancer risk in China’s elderly using CHARLS data.

How were the association and outcomes analyzed?

Solid fuel use for heating was the primary exposure and incident cancer the primary outcome. Logistic regression models adjusted for confounders were applied, and mediation and subgroup analyses were conducted.

What did the study find about cancer risk?

Over a nine-year follow-up, participants using solid fuel heating were statistically associated with a lower cancer risk (adjusted OR = 0.77). Mediation analysis suggested depressive symptoms, LDL-C, and total cholesterol masked parts of the effect.

Why does the conclusion warn against a causal interpretation?

The authors caution that methodological factors and sociodemographic biases—such as healthcare access, socioeconomic status, and detection bias—may drive the paradoxical association rather than a biological causal effect.

Sep 22, 2026

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