A metabolic product of excess niacin promotes vascular inflammation in preclinical models and is associated with increased rates of major adverse cardiovascular events (MACE) in humans. This finding calls into question whether the mandated fortification of foods with niacin should be continued.

Stanley Hazen and colleagues performed an untargeted metabolomics analysis of fasting plasma samples from 1,162 patients with stable cardiac disease (36% women) and found that serum levels of 2PY and 4PY were associated with an increased 3-year risk of MACE. This finding was confirmed in two independent validation cohorts (comprising 2,331 individuals from the USA and 832 individuals from Europe, respectively).