Abstract
OBJECTIVES: This study aimed to investigate trends in the prevalence of early-onset cancer and its association with early-life exposure among US adults. METHODS: This cross-sectional study utilized data from 10 survey cycles between 1999 and 2018 from the National Health and Nutrition Examination Survey (NHANES). Early-onset cancer was defined as the first malignancy diagnosed between the ages of 20 and 49. We conducted trend analyses to assess the prevalence of cancer and early-life exposures. Early-life exposures included diabetes, smoking, overweight and obesity that was experienced before the age of 50. Weighted logistic regression models were employed to identify associations between early-life exposure and early-onset cancer. The outcomes were average biennial percent changes (ABPCs), odds ratios (ORs) and 95 % confidence intervals (CIs). RESULTS: The prevalence of early-onset cancer increased significantly from 2.4 % (95 % CI: 2.0-3.1 %) in 1999-2000 to 3.9 % (95 % CI: 3.0-4.9 %) in 2017-2018, corresponding to an ABPC of 3.7 (95 % CI: 0.8 to 6.6). This increase was primarily observed in non-sex-specific cancers and men. With the exception of smoking, the prevalence of all early-life exposures increased significantly. Early-onset diabetes (OR 1.56, 95 % CI: 1.15-2.12) and early-life smoking (OR 1.55, 95 % CI: 1.34-1.80) were positively associated with early-onset cancer, whereas early-life obesity (OR 0.64, 95 % CI: 0.52-0.79) was negatively associated with early-onset cancer. CONCLUSION: The prevalence of early-onset cancer increased significantly among US adults between 1999 and 2018. Early-onset diabetes and early-life smoking are positively associated with early-onset cancer, whereas early-life obesity is negatively associated with early-onset cancer.