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.