Definitions, Data Source and Methods

Definitions

Hypertension
Systolic blood pressure greater than or equal to 140 mmHg or diastolic blood pressure greater than or equal to 90 mmHg or currently taking prescribed medicine to lower high blood pressure or told by a healthcare professional on two or more different visits that she/he had high blood pressure

Prehypertension
Systolic blood pressure between 120 mmHg and 139 mmHg or diastolic blood pressure between 80 mmHg and 89 mmHg

Normotension
Systolic blood pressure less than 120 mmHg and diastolic blood pressure less than 80 mmHg

Hypertension Awareness
Healthcare professional told that she/he had high blood pressure or ever been told to take prescribed medication to lower high blood pressure among those with hypertension

Hypertension Treatment
Currently taking prescribed medicine to lower high blood pressure

Hypertension Control
Systolic blood pressure less than 140 mmHg and diastolic blood pressure less than 90 mmHg among those with hypertension.

Income to Poverty Ratio
This variable is the ratio of family income to poverty. The Department of Health and Human Services (HHS) poverty guidelines were used as the poverty measure to calculate this ratio. The poverty guidelines vary by family size and geographic location. Income to Poverty Ratio was calculated by dividing family (or individual) income by the poverty guidelines specific to the survey year.


Data Source and Methods

Data from the National Health and Nutrition Examination Surveys (NHANES) 1999-2016 were used to create these visualizations. For estimates among subpopulations with smaller sample sizes, analyses are performed on 4 years of data (two cycles merged) to increase statistical stability. Estimates are age-adjusted to the subpopulations based on the population distribution as of 2000 census.

NHANES is a cross-sectional survey designed to monitor the health and nutritional status of the civilian noninstitutionalized U.S. population using highly stratified, multistage probability designs. The survey consists of interviews conducted in participants’ homes and standardized health examinations conducted in mobile examination centers (MECs). Blood pressure was measured in the MEC by trained physicians using standard protocol. All blood pressure readings were obtained during a single examination visit. After a 5-minute rest in a seated position, participants had up to three brachial systolic and diastolic blood pressure measurements taken 30 seconds apart. An average of up to three systolic and diastolic blood pressure readings was used for systolic and diastolic blood pressure values.

NHANES Oversampling by Race/Ethnicity

For NHANES 1999-2006, oversampling was performed for Mexican-American Hispanic persons. Consequently, the largest proportion Hispanic persons included in NHANES 1999-2006 were Mexican American. In 2007-2010, the sample design was changed to oversample all Hispanic persons. Additionally, Asians were oversampled starting in NHANES 2011-2014 in addition to the ongoing oversample of Hispanics, non-Hispanic blacks, older adults, and low income white and other persons. These changes in oversampling methodology influence interpretation of results for Hispanic populations across NHANES cycles and explain the limited data availability for Asian population in earlier NHANES cycles.

Exclusion Criteria

For the NHANES analyses included in these visualizations, the following exclusion criteria were used:

  • Pregnant women
  • Participants who did not have ≥1 complete non-zero SBP and DBP measurements
  • Participants missing information on self-reported current use of BP-lowering medication, or values for other covariates of interest

For more information about the National Health and Nutrition Examination Survey, please visit the NHANES website at: http://www.cdc.gov/nhanes.