Valid comparisons of hypertension prevalence over time and between populations are difficult owing to differing definitions of hypertension and population age structures. However, studies suggest that raised blood pressure (BP) is increasingly common in most African countries and a major contributor to mortality and morbidity (Cappuccio & Miller 2016). In contrast, early studies found a very low prevalence. Donnison (1929), for example, found no cases of hypertension among 1800 admissions to a rural Kenyan hospital. Rural populations once exhibited less hypertension compared to urban dwellers. However, rural mean BPs and rates of hypertension are now nearing those found in urban areas. For instance, a study of almost 30,000 Malawians found little difference between rural and urban hypertensive prevalence (Price et al. 2018).