Associations of prediagnostic serum liver enzyme levels with lung cancer risk in predominantly low-income African and European Americans

Previous studies have linked liver diseases to lung cancer (LC) risk; however, few studies evaluated the associations of circulating liver enzyme levels with LC risk. We conducted a study of 353 incident LC cases and 646 matched controls with baseline serum alanine aminotransferase (ALT) and of 548 cases and 1032 matched controls with baseline serum alkaline phosphatase (ALP) nested within the Southern Community Cohort Study. Conditional logistic regression and generalized linear models were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) among all study participants and by stratification of potential effect modifiers. Most participants had clinically normal liver enzyme levels. Higher serum ALT levels were associated with reduced LC risk. Compared with the lowest tertile, participants in the second and third tertiles had OR (95% CI) of 0.74 (0.48-1.14) and 0.47 (0.28-0.78) (Ptrend < .01), respectively. The inverse association was observed in African Americans (AAs) and European Americans, which was especially prominent among men, and was seen in both those diagnosed within [ORT3 versus T1 = 0.41 (0.19-0.88)] and beyond [ORT3 versus T1 = 0.35 (0.17-0.73)] a median follow-up time of 39 months. Higher serum ALP levels were associated with increased LC risk among AA men only [ORT3 versus T1 = 2.01 (1.19-3.39)] (Ptrend < .01). Our results indicate that in a predominantly low-income American population, higher serum ALT levels may be related to lower LC risk. Further studies are warranted to confirm our findings and elucidate the potential underlying biological mechanisms of the associations.