Chronic inflammation and risk of lung cancer in older adults in the health, aging and body composition cohort study.

OBJECTIVES: We examined the association between three inflammatory markers (Interleukin (IL)-6, C-reactive protein (CRP), tumor necrosis factor (TNF)-α) and incident lung cancer using baseline, updated, and averaged inflammatory measures in older adults. METHODS: We fitted multivariable Cox models to assess whether circulating levels of inflammation markers were associated with incident lung cancers in the Health Aging, Body and Composition (HealthABC) prospective cohort of 3075 older adults aged 70-79 years at baseline. IL-6 and CRP were measured biennially, whereas TNF-α was measured at baseline. RESULTS: Baseline levels of IL-6 were significantly associated with incident lung cancer risk in a model that adjusted for age, gender, race, and site (Model 1) (Hazard Ratio(T3 vs. T1): 3.34, 95% Confidence Interval: 1.91, 5.85) and in a model adjusted for health factors linked to chronic inflammation (Model 2) (HR (T3 vs. T1): 2.57, 95% CI: 1.41, 4.65). The associations observed in time-updated IL-6 (HR (T3 vs. T1): 2.47, 95% CI: 1.43, 4.28), cumulatively averaged IL-6 (HR (T3 vs. T1): 2.47, 95% CI: 1.43, 4.35), and baseline CRP levels (HR (T3 vs. T1): 1.85, 95% CI: 1.11, 3.08) with incident lung cancer in Model 1 were not statistically significant in Model 2. CONCLUSIONS: Baseline CRP and IL-6 levels were associated with increased risk of lung cancer in Model 1 and both models, respectively. Chronic IL-6 inflammation, as quantified by repeated measures was associated with incident lung cancer in Model 1, but not Model 2. Further research is needed to understand the role of CRP and IL-6 in lung carcinogenesis.