Dietary quality using four dietary indices and lung cancer risk: the Golestan Cohort Study (GCS)

Purpose The lung cancer incidence in Iran has increased almost ten times over the past three decades. In addition to the known causes such as smoking and certain occupational exposure, dietary quality has been suggested to play a role in lung cancer. We aim to explore the association between dietary pattern and lung cancer risk among a Middle East population. Methods Data came from Golestan Cohort Study which included 48,421 participants with 136 lung cancer cases diagnosed during a median follow-up of 12 years. Multivariable Cox proportional hazards regression models were used to calculate the HRs and 95% CI of lung cancer risk by tertile of the four dietary index scores-the Health Eating Index (HEI)-2015, the Alternative Health Eating Index (AHEI)-2010, the Alternative Mediterranean Diet (AMED), and the Dietary Approach to Stop Hypertension (DASH)-Fung. Results A higher DASH-Fung score was inversely associated with risk of lung cancer after adjusting for potential confounders (tertile three vs. tertile one: HR = 0.59 (0.38-0.93); p for trend = 0.07), and p(interaction) with smoking was 0.46. Similar findings were observed among current smokers with the HEI-2015 score (tertile three vs. tertile one: HR = 0.22 (0.08-0.60): p for trend < 0.01), and p(interaction) between smoking and the HEI-2015 score was 0.03. Conclusion In the GCS, consuming a diet more closely aligned with the DASH diet was associated with a reduced risk of lung cancer, which appeared to be independent of smoking status. There was also an inverse link between the HEI-2015 score and lung cancer risk among current smokers. Our finding is particularly important for the Middle East population, as diet may play an important role in cancer prevention and overall health.