Allostatic Load, Cigarette Smoking, and Lung Cancer Risk.

Allostatic load (AL) is a biomarker of chronic stress associated with various chronic diseases. No study has evaluated the relationship between AL and lung cancer risk. To address this gap, we analyzed the association between AL and the development of lung cancer in 344,380 participants from the UK Biobank. During the follow-up period from 2006 to 2020, 2517 participants were diagnosed with incident lung cancer. Participants who developed lung cancer had significantly higher AL compared to cancer-free controls (mean: 3.49 vs. 2.87, < 0.001). In the multivariate analysis, a marginally significant association was observed between higher AL and increased lung cancer risk (per one AL unit: Hazard Ratio [HR] = 1.02, 95% Confidence Interval [CI]: 0.99, 1.04). In the categorical analysis, individuals with high AL (AL > 2) had a 15% higher risk of lung cancer compared to those with low AL (AL ≤ 2) (HR = 1.15, 95% CI: 1.05, 1.25). Stratified analyses revealed that this increased risk was only observed in former (HR = 1.38, 95% CI: 1.06, 1.43) and current smokers (HR = 1.25, 95% CI: 1.10, 1.42) but not in never-smokers (HR = 0.93, 95% CI: 0.74, 1.17). Moreover, we found that demographics, socioeconomics, and other health behaviors could modify the risk association. Finally, among cigarette smoking-related variables, a significant trend of increasing AL was observed with higher pack-years, longer smoking duration, earlier age of smoking initiation, and later age of smoking cessation. These findings suggest that higher AL is associated with an increased risk of lung cancer. The results need to be further confirmed in additional studies.