Early-onset atherosclerotic cardiovascular disease in young adults: Lifestyle, environmental, and psychosocial risk factors

Early-onset atherosclerotic cardiovascular disease (ASCVD) must be distinguished from cardiovascular risk factors and subclinical vascular abnormalities that may arise at younger ages. This narrative review critically examines lifestyle, environmental, metabolic, psychosocial, and inherited determinants among adolescents (10-19 years), young adults (20-39 years), and selected adults aged 40-54 years who remain within commonly used thresholds for premature events. The 40-54-year band is included selectively to bridge younger-adult prevention with guideline-based adult risk assessment and is not intended to redefine the upper age limit of premature ASCVD. Epidemiological evidence demonstrates a substantial burden of cardiovascular disease (CVD) among people aged 15-39 years; however, evidence of increasing clinically manifest ASCVD is less consistent than evidence of rising obesity, hypertension, dyslipidemia, diabetes, nicotine exposure, and subclinical vascular injury. Established causal drivers, including cumulative exposure to apolipoprotein B-containing lipoproteins and cigarette smoking, are distinguished from predominantly associative evidence concerning sleep disruption, psychosocial stress, e-cigarette use, and air pollution. Prevention should combine population-level health promotion with age-appropriate clinical risk assessment, including lipid screening and measurement of lipoprotein(a) at least once in adulthood, with additional targeted evaluation for familial hypercholesterolemia, a family history of premature ASCVD, obesity, hypertension, diabetes, chronic kidney disease, and smoking or vaping. Coronary artery calcium scoring and carotid imaging are not recommended as universal screening tests for asymptomatic young people, although they may refine clinical decisions in carefully selected adults. Digital tools may support engagement but should complement, rather than replace, validated clinical care and public-health measures.