BackgroundFew research has explored the risk of distant metastasis dynamically changes with age in non-small cell lung cancer patients. The objective of this study was to explore the risk factors of developing distant metastasis with changing age. MethodsThis retrospective cohort study was based on a large population of patients with non-small cell lung cancer from the SEER database. Logistic regression was applied to identify risk factors for distant metastasis. The clinicopathological features were compared between the young group (≤50 years old) and the old group (>50 years old). Dose-response analyses were conducted to explore risk of distant metastasis changes with age. ResultsA total of 18,711 patients were studied in this study. According to the univariate and multivariate logistic regression analyses, ten factors were found to be risk factors for distant metastasis. Young patients have a greater incidence of each pattern of metastasis. However, the survival time of younger patients was longer. Dose-response analyses indicated that the risks of pleural or pericardial metastasis and overall distant metastasis gradually decreased with age at younger ages, but they intend to increase at older ages. ConclusionsAge, sex, ethnicity, histology, T category, N category, differentiation grade, primary site of the tumor, ipsilateral metastases are factors associated with distant metastasis in NSCLC patients. Young patients have a greater risk of distant metastasis. The distant metastasis may decrease with the increasing age in patients younger than 70 years, but increase with the climb of age for patients older than 70 years.