| Characteristic | Overall (n=6960) |
Education
|
||||
|---|---|---|---|---|---|---|
| 8th Grade (n=423) | 9-11th Grade (n=866) | High School (n=1460) | Some College (n=2175) | College Grad (n=2036) | ||
| Age, years | 47 (17) | 55 (18) | 48 (18) | 48 (18) | 45 (17) | 47 (15) |
| Sex | ||||||
| Female | 3,514 (50%) | 190 (45%) | 386 (45%) | 735 (50%) | 1,142 (53%) | 1,061 (52%) |
| Male | 3,446 (50%) | 233 (55%) | 480 (55%) | 725 (50%) | 1,033 (47%) | 975 (48%) |
| Race/ethnicity | ||||||
| Black | 771 (11%) | 21 (5.0%) | 148 (17%) | 208 (14%) | 268 (12%) | 126 (6.2%) |
| Hispanic | 395 (5.7%) | 63 (15%) | 65 (7.5%) | 83 (5.7%) | 110 (5.1%) | 74 (3.6%) |
| Mexican | 582 (8.4%) | 168 (40%) | 134 (15%) | 119 (8.2%) | 111 (5.1%) | 50 (2.5%) |
| White | 4,697 (67%) | 131 (31%) | 481 (56%) | 999 (68%) | 1,517 (70%) | 1,569 (77%) |
| Other | 515 (7.4%) | 40 (9.5%) | 38 (4.4%) | 51 (3.5%) | 169 (7.8%) | 217 (11%) |
| Systolic BP, mmHg | 121 (17) | 126 (19) | 122 (18) | 122 (17) | 121 (17) | 118 (16) |
| Values are mean (SD) for continuous variables and n (%) for categorical variables. | ||||||
Abstract
Background: Socioeconomic factors, including educational attainment, have been associated with cardiovascular health outcomes. This study examines the association between education level and systolic blood pressure using nationally representative data.
Methods: We analyzed data from 6960 adults aged 20 years and older from the National Health and Nutrition Examination Survey (NHANES) 2009-2012. Linear regression was used to estimate the association between education level and systolic blood pressure, adjusting for sex and race/ethnicity.
Results: Higher education levels were associated with lower systolic blood pressure. Compared to participants with less than 9th grade education, college graduates had lower mean systolic blood pressure (coefficient: -10 mmHg).
Conclusions: Education level is inversely associated with blood pressure in U.S. adults. These findings highlight the importance of addressing social determinants of cardiovascular health.
Introduction
Hypertension affects nearly half of all adults in the United States and is a major risk factor for cardiovascular disease (1). Socioeconomic factors, including educational attainment, have been consistently associated with cardiovascular health outcomes (2,3).
Education may influence blood pressure through multiple pathways, including health behaviors, access to healthcare, and chronic stress (4). Understanding the relationship between education and blood pressure can inform public health interventions aimed at reducing cardiovascular health disparities.
This study examines the association between education level and systolic blood pressure using data from the National Health and Nutrition Examination Survey (NHANES), a nationally representative survey of the U.S. civilian population (5).
Methods
Study Population
We analyzed data from the NHANES 2009-2012 cycles, accessed through the R package NHANES (6). The NHANES dataset contains 6,960 observations that have been resampled to remove oversampling effects, allowing the data to be treated as a simple random sample for educational purposes.
We included adults aged 20 years and older with complete data on education level, blood pressure measurements, sex, and race/ethnicity. The final analytic sample included 6,960 participants.
Measures
Outcome: Systolic blood pressure was measured as the average of up to three readings (variable: BPSysAve).
Exposure: Educational attainment was categorized as: 8th grade or less, 9-11th grade, high school graduate, some college, or college graduate.
Covariates: We adjusted for sex (male/female) and race/ethnicity (Mexican, Hispanic, White, Black, Other).
Statistical Analysis
We used descriptive statistics to characterize the study population. Linear regression was used to estimate the association between education level and systolic blood pressure, with adjustment for sex and race/ethnicity.
All analyses were conducted in R using the gtsummary package for tables (7) and ggplot2 for figures (8).
Results
Participant Characteristics
The study included 6,960 participants. The mean age was 47.2 years (SD = 16.9), and 50.5% were female. The mean systolic blood pressure was 121 mmHg (SD = 17.1).
Participant characteristics by education level are presented in Table 1.
Blood Pressure Distribution
Figure 1 shows the distribution of systolic blood pressure by education level. Blood pressure generally decreased with increasing education, with college graduates having the lowest mean blood pressure.
Association Between Education and Blood Pressure
Results of the linear regression analysis are presented in Table 2. Compared to participants with 8th grade education or less, those with higher education levels had lower systolic blood pressure. College graduates had a coefficient of -10 mmHg compared to the reference group.
Subgroup Analysis
To examine whether the education-blood pressure association varied across demographic groups, we conducted subgroup analyses stratified by sex and race/ethnicity (Figure 2). The inverse association between college education and blood pressure was observed across most subgroups, though the magnitude varied. Detailed numerical results are provided in Table S1.
Sensitivity Analysis
We examined the robustness of our findings using different blood pressure thresholds to define hypertension (Figure 3). The protective association of higher education was consistent across thresholds ranging from 120 to 150 mmHg. Detailed numerical results are provided in Table S2.
Discussion
This study found an inverse association between educational attainment and systolic blood pressure in a nationally representative sample of U.S. adults. Participants with higher education levels had lower mean blood pressure compared to those with less education.
These findings are consistent with previous research documenting socioeconomic gradients in cardiovascular health (2). Several mechanisms may explain this relationship, including differences in health behaviors, access to healthcare, occupational exposures, and chronic stress associated with socioeconomic position (3,4).
Strengths and Limitations
Strengths of this study include the use of nationally representative data and objective blood pressure measurements. However, several limitations should be noted. First, this is a cross-sectional analysis, limiting our ability to establish causal relationships. Second, we did not account for the complex survey design (sampling weights) as this analysis was conducted for educational purposes. Third, residual confounding by unmeasured factors cannot be ruled out.
Conclusions
Education level is inversely associated with blood pressure in U.S. adults. These findings highlight the importance of addressing social determinants of health in efforts to reduce cardiovascular disease burden.
References
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Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey [Internet]. 2023. Available from: https://www.cdc.gov/nchs/nhanes/index.htm
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Pruim R. NHANES: Data from the US National Health and Nutrition Examination Study [Internet]. 2015. Available from: https://CRAN.R-project.org/package=NHANES
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Sjoberg DD, Whiting K, Curry M, Lavery JA, Larmarange J. Reproducible summary tables with the gtsummary package. The R Journal. 2021;13(1):570–80.
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Wickham H. ggplot2: Elegant Graphics for Data Analysis [Internet]. Springer-Verlag New York; 2016. Available from: https://ggplot2.tidyverse.org