Abstract 7385: Shifting landscapes of cancer-related lifestyle risk factors among U.S. young adults under age 50

Abstract Introduction: The rising incidence of early-onset cancers among younger adults in the U.S. and globally has been alarming over the past decades. Understanding the evolving patterns of cancer-related lifestyle factors in younger populations is crucial for identifying key risk factors for targeted prevention and emerging exposures for etiological research. Methods: We utilized the National Health and Nutrition Examination Survey (NHANES) (1999-2023) to characterize age-specific patterns and trends of established risk factors for multiple cancers, including body mass index (BMI), current smoking, alcohol consumption, and physical activity, among adults under age 50. We also examined emerging dimensions of these behaviors, such as weight history, e-cigarette use, binge drinking, and sedentary behaviors. Results: Across all age groups under 50, mean BMI steadily increased (27.7 to 29.5 kg/m2), with a sharper increase in later survey cycles for age groups 30-39 and 40-49. The proportion of overweight/obese children and adolescents increased (30.0% to 33.8%). Trends for highest self-reported lifetime weight also followed an upward trajectory (185 to 202 lbs), with 30-39 age group reporting the highest figures in the past decade. Current smoking prevalence decreased across all age groups throughout this period (29.0% to 14.2%), but 30-39 age group exhibited a stabilizing trend recently. While the mean age of smoking initiation among current smokers decreased slightly (17.5 to 17.0 yrs), adolescents reported smoking a full cigarette at a much younger age in the past decade (14.8 to 13.1 yrs). Meanwhile, prevalence of recent e-cigarette use rose sharply (2.8% to 9.0%), with the highest rates in 20-29 age group. While alcohol consumption decreased slightly across all age groups (3.3 to 3.0 drinks/day among drinkers), prevalence of binge drinking more than doubled (11.4% to 27.5%). The 20-29 age group consistently reported highest levels of alcohol intake and binge drinking. Younger adults showed higher prevalence of moderate/vigorous physical activity (58.5% to 61.3%); however, the daily time spent on such activity declined (229 to 206 minutes), particularly among 20-29 and 30-39 age groups. Sedentary behavior time increased for all age groups (342 to 371 minutes), with the highest level observed in adolescents and recent rising trends in 20-29 and 30-39 age groups. Conclusion: Analyses of nationally representative data in the U.S. revealed substantial shifts in the landscape of cancer-related lifestyle risk factors, underscoring the urgent need to understand the biological impact of age of initiation, cumulative and peak exposures, emerging behaviors, and age-specific exposure patterns on cancer initiation and progression in younger populations. These insights are crucial for informing the development of tailored, life-stage-focused prevention strategies to combat early-onset cancers. Citation Format: Sina Azadnajafabad, Xiaoyu Zong, Nicholas Jeschke, Yichen Sun, Duo Ren, Yin Cao, on behalf of Cancer Grand Challenges Team PROSPECT. Shifting landscapes of cancer-related lifestyle risk factors among U.S. young adults under age 50 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7385.