IARC 60th Anniversary - 19-21 May 2026
Session : 20/05/26 - Posters
Long-term PM2.5 and lung cancer risk in a low-exposure setting: evidence from Northern Ireland for prevention action
ALHATTAB R. 1,2, MCKINLEY J. 3, HUNTER R. 1, DELARGY C. 1, WALLACE S. 1, BENNETT D. 4, FITZPATRICK D. 4, MITCHELL H. 4, MCGUINNESS B. 1, SCOTT A. 4, MCKAY G. 1, BOUAOUN L. 5, MCCORMACK V. 5, MIDDLETON D. 1
1 Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom; 2 Ibn Sina University for Medical Sciences, Amman , Jordan; 3 Geography, School of Natural and Built Environment, Queen’s University Belfast, Belfast, United Kingdom; 4 Northern Ireland Cancer Registry, Centre for Public Health, Queen’s University Belfast, Belfast, United Kingdom; 5 Environment and Lifestyle Epidemiology Branch, International Agency for Research on Cancer (IARC-WHO), Lyon, France
Background: Preventing lung cancer increasingly depends on identifying modifiable risks beyond tobacco. Ambient fine particulate matter (PM2.5) is carcinogenic, yet evidence from lower-exposure settings and for sex-specific susceptibility remains limited-information that is crucial for prevention innovation and risk stratification.
Objectives: (1) quantify the association between long-term residential PM2.5 exposure and lung cancer risk in Northern Ireland, (2) estimate the population attributable fraction (PAF) for lung cancer associated with PM2.5 above 10 µg/m³, and (3) translate the PAF into the number of potentially preventable cases under a counterfactual reduction scenario.
Methods: We conducted a population-based case-control study using cancer registry-ascertained lung cancer cases and population controls. Long-term exposure was defined as an 8-year mean PM2.5 assigned by linking residential postcodes to 1 km² modelled concentration surfaces (high-resolution exposure innovation for population prevention). We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression with key confounders including smoking and area-level deprivation. PM2.5 was modelled in tertiles and continuously; we estimated population attributable fractions (PAFs) for exposure above 10 µg/m³.
Results: Compared with the lowest PM2.5 tertile (<7.4 µg/m³), the highest tertile (>9.6 µg/m³) was associated with increased lung cancer odds (OR 1.37; 95% CI 1.12–1.68). In sex-stratified analyses, the association was stronger among women (OR 1.79; 95% CI 1.32–2.44) and was not evident among men. On a continuous scale, lung cancer odds increased by 6% per 1 µg/m³ higher PM2.5 (OR 1.06; 95% CI 1.03–1.10). Applying the 10 µg/m³ threshold suggested that approximately 10% of lung cancer cases could be attributable to PM2.5 above this level (≈137 potentially preventable cases annually under full compliance).
Conclusions/Implications: In a low-pollution setting, small differences in long-term PM2.5 were linked to meaningful lung cancer risk, with signals of greater susceptibility among women. High-resolution exposure assignment supports innovative prevention targeting, and the burden estimates reinforce the cancer-prevention value of accelerating air-quality improvements toward lower PM2.5 concentrations.