Social, Behavioral, and Metabolic Risk Factors and Racial Disparities in Cardiovascular Disease Mortality in U.S. Adults : An Observational Study

Abstract

Background: Cardiovascular disease (CVD) mortality is persistently higher in the Black population than in other racial and ethnic groups in the United States.

Objective: To examine the degree to which social, behavioral, and metabolic risk factors are associated with CVD mortality and the extent to which racial differences in CVD mortality persist after these factors are accounted for.

Design: Prospective cohort study.

Setting: NHANES (National Health and Nutrition Examination Survey) 1999 to 2018.

Participants: A nationally representative sample of 50 808 persons aged 20 years or older.

Measurements: Data on social, behavioral, and metabolic factors were collected in each NHANES survey using standard methods. Deaths from CVD were ascertained from linkage to the National Death Index with follow-up through 2019.

Results: Over an average of 9.4 years of follow-up, 2589 CVD deaths were confirmed. The age- and sex-standardized rates of CVD mortality were 484.7 deaths per 100 000 person-years in Black participants, 384.5 deaths per 100 000 person-years in White participants, 292.4 deaths per 100 000 person-years in Hispanic participants, and 255.1 deaths per 100 000 person-years in other race groups. In a multiple Cox regression analysis adjusted for all measured risk factors simultaneously, several social (unemployment, low family income, food insecurity, lack of home ownership, and unpartnered status), behavioral (current smoking, lack of leisure-time physical activity, and sleep <6 or >8 h/d), and metabolic (obesity, hypertension, and diabetes) risk factors were associated with a significantly higher risk for CVD death. After adjustment for these metabolic, behavioral, and social risk factors separately, hazard ratios of CVD mortality for Black compared with White participants were attenuated from 1.54 (95% CI, 1.34 to 1.77) to 1.34 (CI, 1.16 to 1.55), 1.31 (CI, 1.15 to 1.50), and 1.04 (CI, 0.90 to 1.21), respectively.

Limitation: Causal contributions of social, behavioral, and metabolic risk factors to racial and ethnic disparities in CVD mortality could not be established.

Conclusion: The Black-White difference in CVD mortality diminished after adjustment for behavioral and metabolic risk factors and completely dissipated with adjustment for social determinants of health in the U.S. population.

Primary funding source: National Institutes of Health.

Figure 1.. Multiple-adjusted hazard ratios (95% CI) of race/ethnicity and social, behavioral, and metabolic risk factors associated with cardiovascular disease mortality in the US adults aged 20 and older, NHANES 1999-2018

* Healthy eating index scores range from 0 to 100 with a higher score indicating greater consistency of the diet with the Dietary Guidelines for Americans. The median healthy eating index score was 52 among NHANES 1999-2018 participants. Obesity was defined as body mass index ≥30 kg/m². Central obesity was defined as waist circumference ≥102 cm in men and ≥88 cm in women. Hypertension was defined as systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg or use of antihypertensive medications. Diabetes was defined as fasting glucose ≥126mg/dL or hemoglobin A1c ≥6.5% or diagnosed diabetes. † Adjustment for age, sex, race/ethnicity, and all other social, behavioral, and metabolic risk factors listed in the figure.

Figure 2.. Hazard ratio of cardiovascular disease mortality associated with the number of social, behavioral, and metabolic risk factors in the US population.

(A). hazard ratio of cardiovascular disease mortality by the number of social risk factors; (B). hazard ratio of cardiovascular disease mortality by the number of behavioral risk factors; (C). hazard ratio of cardiovascular disease mortality by the number of metabolic risk factors; (D). hazard ratio of cardiovascular disease mortality by the number of overall social, behavioral, and metabolic risk factors. Error bars indicate 95% CIs. All hazard ratios were stratified by NHANES cycles and adjusted for age, sex, race and ethnicity.

Figure 3.. Hazard ratio of Black-White difference in cardiovascular mortality adjusting for metabolic, behavioral, and social risk factors in the US adults aged 20 and older, NHANES 1999-2018

Metabolic risk factors included obesity, central obesity, hypertension, diabetes, and total-to-HDL cholesterol ratio ≥5. Behavioral risk factors included current smoking, healthy eating index score <52, no leisure-time physical activity, and sleep duration <6 or >8 hours per day. Social risk factors included unemployed, family income-to-poverty ratio <300%, marginal or low food security, not owning a home, less than high school education, no regular health care access, no private health insurance, and not married nor living with a partner.