Analysis of 4,452 US adolescents followed for 21 years reveals that frequent alcohol consumption during ages 12-19, especially combined with smoking, produces dramatically different cardiovascular outcomes based on family financial circumstances. Among teens from financially struggling families, frequent drinking led to 11.1 percentage points more cardiovascular disease and hypertension cases by ages 33-43 compared to peers from stable financial backgrounds. Alcohol use alone showed a 9.7 percentage point differential effect. This suggests adolescents from disadvantaged backgrounds face heightened biological or environmental susceptibility to alcohol's cardiovascular damage. The finding challenges assumptions that health behaviors affect everyone equally, revealing how socioeconomic position amplifies certain risks during critical developmental windows. While breakfast skipping and physical inactivity showed weaker associations, the alcohol-smoking combination created the starkest health disparities. This differential vulnerability pattern could inform targeted prevention strategies, suggesting that universal adolescent alcohol interventions might yield disproportionate benefits for disadvantaged youth. However, as an unreviewed preprint using observational data, these results require peer validation and cannot establish definitive causation between teenage behaviors and decades-later cardiovascular outcomes.