In recent years, bariatric surgery has become an increasingly used therapeutic option for morbid obesity. The effect of weight loss after bariatric surgery on the predicted risk of coronary heart disease (CHD) has not previously been studied. We evaluated baseline (preoperative) and follow-up (postoperative) body mass index, CHD risk factors, and Framingham risk scores (FRSs) for 109 consecutive patients with morbid obesity who lost weight after laparoscopic Roux-en-Y gastric bypass surgery. Charts were abstracted using a case-report form by a reviewer blinded to the FRS results. The study included 82 women (75%) and 27 men (25%) (mean age 46 +/- 10 years). Mean body mass index values at baseline and follow-up were 49 +/- 8 and 36 +/- 8 kg/m(2), respectively (p <0.0001). During an average follow-up of 17 months, diabetes, hypertension, and dyslipidemia resolved or improved after weight loss. Thus, the risks of CHD as predicted by FRS decreased by 39% in men and 25% in women. The predicted 10-year CHD risks at baseline and follow-up were 6 +/- 5% and 4 +/- 3%, respectively (p < or =0.0001). For those without CHD, men compared favorably with the age-matched general population, with a final 10-year risk of 5 +/- 4% versus an expected risk of 11 +/- 6% (p <0.0001). Likewise, women achieved a level below the age-adjusted expected 10-year risk of the general population, with a final risk of 3 +/- 3% versus 6 +/- 4% (p <0.0001). In conclusion, weight loss results in a significant decrease in FRS 10-year predicted CHD risk. Bariatric surgery decreases CHD risk to rates lower than the age- and gender-adjusted estimates for the general population. These data suggest substantial and sustained weight loss after bariatric surgery may be a powerful intervention to decrease future rates of myocardial infarction and death in the morbidly obese.