We read with interest the article by Nguyen et al1 evaluating the association between proton pump inhibitor (PPI) use and ischemic stroke. The authors found that PPI use was associated with a significant increase in the risk of ischemic stroke after adjustment for established risk factors for stroke including smoking status, body mass index, physical activity, dietary quality, alcohol use, menopausal hormone use in women, multivitamin use, regular aspirin use, regular nonaspirin nonsteroidal anti-inflammatory drug, use and personal history of hypertension, hyperlipidemia, coronary artery disease, or diabetes.