Red meat, Mediterranean diet and lung cancer risk among heavy smokers in the COSMOS screening study

To assess whether intake of selected foods and food groups and adherence to a Mediterranean diet are associated with lung cancer risk in heavy smokers. In the context of a lung cancer screening programme, we invited asymptomatic volunteers, aged 50 years or more, current smokers or recent quitters, who had smoked at least 20 pack-years, to undergo annual low-dose computed tomography. We assessed participants' diet at baseline using a self-administered food frequency questionnaire and calculated their average daily food intake using an ad hoc computer program and determined their alternate Mediterranean diet (aMED) score. We used Cox proportional hazards regression to assess the association between selected food items, beverages and the aMED score and lung cancer risk. During a mean screening period of 5.7 years, 178 of 4336 participants were diagnosed with lung cancer. At multivariable analysis, red meat consumption was associated with an increased risk of lung cancer [hazard ratio (HR) Q4 versus Q1, 1.73; 95% confidence interval (CI) 1.15-2.61; P-value for trend 0.002], while tea consumption (HR for one or more cup/day versus none, 0.56; 95% CI 0.31-0.99; P-value for trend 0.04) and adherence to a Mediterranean diet (HR for aMED >= 8 versus < 1, 0.10; 95% CI 0.01-0.77) were significantly associated with reduced lung cancer risk. Among heavy smokers, high red meat consumption and low adherence to a Mediterranean diet are associated with increased risk of lung cancer.