Anstey DE, et al. - In this study performed on 199 African Americans with clinic-measured systolic/diastolic blood pressure (BP) ≥140/90 mm Hg in the Jackson Heart Study, researchers estimated the commonness of white coat hypertension (WCH) using out-of-clinic BP in the daytime period; daytime and 24-hour periods; and daytime, 24-hour, and nighttime periods. Among patients with WCH and 374 patients with sustained normotension (ie, non-hypertensive clinic, daytime, 24-hour, and nighttime BP), they measured left ventricular mass index (LVMI). The use of daytime BP; daytime and 24-hour BP; and daytime, 24-hour, and nighttime BP provided WCH prevalence estimated to be 29.6%, 21.1%, and 10.6%, respectively. Overall, the commonness of WCH among African Americans was overestimated when only daytime BP was used.