Cardiovascular Health of Middle-Aged U.S. Adults by Income Level, 1999 to March 2020

BACKGROUND: Although cardiovascular mortality has increased among middle-aged U.S. adults since 2011, how the burden of cardiovascular risk factors has changed for this population by income level over the past 2 decades is unknown. OBJECTIVE: To evaluate trends in the prevalence, treatment, and control of cardiovascular risk factors among low-income and higher-income middle-aged adults and how social determinants contribute to recent associations between income and cardiovascular health. DESIGN: Serial cross-sectional study. SETTING: NHANES (National Health and Nutrition Examination Survey), 1999 to March 2020. PARTICIPANTS: Middle-aged adults (aged 40 to 64 years). MEASUREMENTS: Age-standardized prevalence of hypertension, diabetes, hyperlipidemia, obesity, and cigarette use; treatment rates for hypertension, diabetes, and hyperlipidemia; and rates of blood pressure, glycemic, and cholesterol control. RESULTS: The study population included 20 761 middle-aged adults. The prevalence of hypertension, diabetes, and cigarette use was consistently higher among low-income adults between 1999 and March 2020. Low-income adults had an increase in hypertension over the study period (37.2% 95% CI, 33.5% to 40.9% to 44.7% CI, 39.8% to 49.5%) but no changes in diabetes or obesity. In contrast, higher-income adults did not have a change in hypertension but had increases in diabetes (7.8% CI, 5.0% to 10.6% to 14.9% CI, 12.4% to 17.3%) and obesity (33.0% CI, 26.7% to 39.4% to 44.0% CI, 40.2% to 47.7%). Cigarette use was high and stagnant among low-income adults (33.2% CI, 28.4% to 38.0% to 33.9% CI, 29.6% to 38.3%) but decreased among their higher-income counterparts (18.6% CI, 13.5% to 23.7% to 11.5% CI, 8.7% to 14.3%). Treatment and control rates for hypertension were unchanged in both groups (>80%), whereas diabetes treatment rates improved only among the higher-income group (58.4% CI, 44.4% to 72.5% to 77.4% CI, 67.6% to 87.1%). Income-based disparities in hypertension, diabetes, and cigarette use persisted in more recent years even after adjustment for insurance coverage, health care access, and food insecurity. LIMITATION: Sample size limitations could preclude detection of small changes in treatment and control rates. CONCLUSION: Over 2 decades in the United States, hypertension increased in low-income middle-aged adults, whereas diabetes and obesity increased in their higher-income counterparts. Income-based disparities in hypertension, diabetes, and smoking persisted even after adjustment for other social determinants of health. PRIMARY FUNDING SOURCE: National Institutes of Health.