Diet quality and lung cancer incidence in a low-income population in the United States.

Background: Although tobacco smoking is the leading cause of lung cancer, interest in the relationship of diet quality on risk has been growing.

Methods: We examined the association between Healthy Eating Index-2010 (HEI-10) at enrollment and lung cancer incidence among 70,802 participants in a predominantly African American and low-income prospective cohort in the southern United States. Outcomes were ascertained through linkages with state cancer registries and the National Death Index (NDI). Hazard ratios by HEI-10 quartiles were assessed using Cox proportional hazard models adjusted for potential confounders.

Results: During ≤16 years of follow-up, 1454 incident lung cancers were identified. The lowest HEI-10 quartile compared to the highest was adversely associated with lung cancer risk (HR: 1.89, 95% CI 1.16-3.07) among male former smokers and female never smokers (HR: 2.58, 95% CI 1.06-6.28).

Conclusions: Low-quality diet was associated with increased lung cancer risk among male former smokers and female never smokers but cautious interpretation of the findings should be taken due to the small number of lung cancers among never smokers and the possibility of residual confounding by smoking in ever smokers.