• Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Laboratory of Cancer Biology Department of Oncology, University of Oxford, Oxford, UK.
• Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Clinical Nutrition, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.

BACKGROUND: Despite the possible contribution of dairy products to the development or prevention of cancers, there is a lack of epidemiological evidence linking low-fat dairy consumption to the risk of developing lung cancer. This research was conducted to fill this knowledge gap.

METHODS: The data for this research were collected from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The Cox proportional risk model was employed to evaluate the link between low-fat dairy consumption and the risk of developing lung cancer. Hazard ratios (HRs) and 95% confidence intervals (CIs) were measured in both unadjusted and adjusted models. A series of predefined subgroup analyses were performed to identify potential effect modifiers, and several sensitivity analyses were conducted to assess the stability of the findings.

RESULTS: The study included data from 98,459 individuals. During a total of 869,807.9 follow-up person-years, 1642 cases of lung cancer were observed, with an incidence of 0.189 cases for every 100 person-years. In the fully adjusted model, participants in the highest quartile of low-fat dairy consumption had a significantly decreased risk of lung cancer compared to the ones in the lowest quartile (HR_{quartile 4 vs. 1} : 0.769, 95% CI: 0.664, 0.891, p_trend  = 0.005). The restricted cubic spline plot revealed an inverse nonlinear dose-response relationship between low-fat dairy consumption and lung cancer risk (p_nonlinearity  = 0.008). Subgroup analyses demonstrated that the inverse association was stronger among participants with higher daily caloric intake (p_interaction  = 0.031). Various sensitivity analyses produced consistent results.

CONCLUSION: Consuming more low-fat dairy products is significantly linked to a reduced risk of developing lung cancer, indicating that an appropriate increase in the use of low-fat dairy products may help prevent lung cancer.