Income Disparities in Absolute Cardiovascular Risk and Cardiovascular Risk Factors in the United States, 1999-2014

Importance

Large improvements in the control of risk factors for cardiovascular disease have been achieved in the United States, but it remains unclear whether adults in all socioeconomic strata have benefited equally.

Objective

To assess temporal trends in 10-year predicted absolute cardiovascular risk and cardiovascular risk factors among US adults in different socioeconomic strata.

Design, Setting, and Participants

A cross-sectional analysis was conducted using data on adults 40 to 79 years of age without established cardiovascular disease from the 1999 to 2014 National Health and Nutrition Examination Survey.

Exposures

Socioeconomic status was based on the family income to poverty ratio and participants were divided into the following 3 groups: high income (family income to poverty ratio, ≥4), middle income (>1 and <4), or at or below the federal poverty level (≤1).

Main Outcomes and Measures

We assessed predicted absolute cardiovascular risk using the pooled cohort equation. We assessed the following 4 risk factors: systolic blood pressure, smoking status, diabetes, and total cholesterol.

Results

Of the 17 199 adults whose data were included in the study (8828 women and 8371 men; mean age, 54.4 years), from 1999-2014, trends in the percentage of adults with predicted absolute cardiovascular risk of 20% or more, mean systolic blood pressure, and the percentage of current smokers varied by income strata (P ≤ .02 for interaction). For adults with incomes at or below the federal poverty level, there was little evidence of a change in any of these outcomes across survey years (cardiovascular risk ≥20%, 14.9% [95% CI, 12.9%-16.8%] in 1999-2004; 16.5% [95% CI, 13.7%-19.2%] in 2011-2014;P = .41; mean systolic blood pressure, 127.6 [95% CI, 126.1-129.0] mm Hg in 1999-2004; 126.8 [95% CI, 125.2-128.5] mm Hg in 2011-2014;P = .44; and smoking, 36.5% [95% CI, 32.1%-41.0%] in 1999-2004; 36.0% [95% CI, 31.1%-40.8%] in 2011-2014;P = .87). For adults in the high-income stratum, these variables decreased across survey years (cardiovascular risk ≥20%, 12.0% [95% CI, 10.7%-13.3%] in 1999-2004; 9.5% [95% CI, 8.2%-10.7%] in 2011-2014;P = .003; systolic blood pressure, 126.0 [95% CI, 125.0-126.9] mm Hg in 1999-2004; 122.3 [95% CI, 121.3-123.3] mm Hg in 2011-2014;P < .001; and smoking, 14.1% [95% CI, 12.0%-16.2%] in 1999-2004; 8.8% [95% CI, 6.6%-11.0%] in 2011-2014;P = .001). Trends in the percentage of adults with diabetes and the mean total cholesterol level did not vary by income.

Conclusions and Relevance

Adults in each socioeconomic stratum have not benefited equally from efforts to control cardiovascular risk factors.