The National Health and Nutrition Examination Survey (NHANES) data has provided important epidemiologic information on the prevalence and control of hypertension in the United States between 1960 and 2008 [1-4]. Overall, the prevalence is higher in older individuals, non-Hispanic blacks, and women (figure 1). The prevalence of hypertension in children is discussed separately. (See "Definition and diagnosis of hypertension in children and adolescents".)
It remains unclear why non-Hispanic blacks are more likely to become hypertensive. Both genetic and environmental factors are probably important, one of which may be a greater likelihood of low birth weight, which appears to predict higher pressures in adulthood. (See "Possible role of low birth weight in the pathogenesis of primary (essential) hypertension".)
NHANES data from 2007 to 2008 and United States Census bureau information demonstrated a 28 to 30 percent prevalence of hypertension in the 18 year and older population of the United States [2,3,5-7]. This translates into approximately 65 million hypertensives in the adult population in the United States, which is substantially higher than the 43.2 million estimate derived from the 1988-1991 NHANES-III survey [1,3,6].
One possible explanation for the increased prevalence of hypertension reported in the latest survey data is that, over the last decade, there has been a marked increase in obesity and average body mass index . It is estimated, for example, that one-half of the relative increased prevalence of hypertension may be due to an increased weight of the average individual.
A higher prevalence of hypertension has also been found in other industrialized societies. In surveys similar to the United States NHANES performed in Canada and Europe, the age- and sex-adjusted prevalence of hypertension (defined as 140/90 mmHg or higher) ranged from 20 to 55 percent (figure 1) [5,8].