Although since 1950, the incidence, prevalence, and mortality from cardiovascular diseases (CVD) have declined, coronary heart disease (CHD) and stroke (the two major forms of CVD) remain the leading causes of deaths in the United States of America (U.S.) (1–3). In 2010, 379,559 Americans died of CHD; it alone caused about one of every six deaths in the U.S. Approximately, every 1 min and 23 s, an American will die of CHD. Stroke caused about 1 of every 19 deaths. On average, every 40 s, someone in the U.S. has a stroke, and someone dies of one approximately every 4 min (1). In the U.S. more than 33%, or more than 100 million persons, identified themselves as belonging to a racial or ethnic minority population. Furthermore, it is well-known that CVD disproportionately affect the U.S. minority populations. However, limited studies address and provide updated evidence of the burden of CVD and its association with preventable risk factors across sub-groups of minority populations. In the present study, we aimed to examine the burden and health disparity of CVD and diabetes mellitus (DM), and their associations with lifestyle-related factors across multi-racial and ethnic groups in the U.S. We hypothesized that there were significant differences in the prevalence of CVD and DM and in the magnitude of the associations between CVD, DM, and risk factors across racial and ethnic groups. In the study, we used data from the most recent studies of the 2012 and 2013 National Health Interview surveys (NHIS). Findings from the study may provide significant evidence to health policy makers and moving forward prevention strategy and practice toward a significant reduction of cardiovascular disparity in the nation.

Participants aged 18 years and older in the 2012 and 2013, NHIS were included in the study. The NHIS, a cross-sectional study, is an annual in-person interview-administered survey of health status and behaviors among the U.S. non-institutionalized population. One adult per household was chosen randomly to participate (4). We combined recently released 2012 and 2013 NHIS data in order to ensure the study sample size and statistical power were big enough when testing differences in cardiovascular health by racial/ethnic groups, Non-Hispanic (NH) Whites, NH-Blacks, NH-Asians, Hispanics, as well as subgroups of NH-Asians (i.e., Chinese, Indian, and Filipino groups). We examine the subgroups of NH-Asians because they are one of the fastest-growing racial/ethnic groups in the U.S. (5). Of 69,082 total participants aged 18 and older, we excluded 761 with missing values on race/ethnicity, yielding a final analytic sample of 68,321 adults. Data used in the study were de-identified and publicly available from the National Center for Health Statistics. Therefore, no specific institutional review board’s approval was needed (4).

This study focused on four major CVD related chronic conditions: hypertension, CHD, stroke, and DM. These conditions were defined on the basis of participants’ self-reports of diagnoses made by a doctor or health professional. Covariates included age, gender, education attainments ( <high-school graduate, high-school graduate, and ≥college), body mass index [BMI, calculated by weight (kg)/height (m²)], cigarette smoking (never smoked, formerly smoked, or currently smoke), alcohol consumption (non-drinker: <12 drinks in entire life, former drinker: no drinks in previous year, and current drinker), and physical activity. BMI was classified into four groups on the basis of the World Health Organization (WHO) definition (underweight: <18.5, normal weight: 18.5–24.9, overweight: 25–29.9, and obesity: ≥30 kg/m²). Physical activity status was grouped on the basis of current guidelines (active: ≥150 min per week of moderate-intensity equivalent leisure-time aerobic activity; insufficiently active: 10–149 min per week of moderate-intensity equivalent leisure-time aerobic activity) (6–8).

The present study, using data from nationally representative samples of the U.S. NHIS provides new evidence of cardiovascular epidemiology and heath disparity across the four largest racial/ethnic populations in the U.S. The results confirm that NH-Blacks had significantly higher odds of hypertension, and NH-Blacks, NH-Asians, and Hispanics had significantly higher odds of DM than NH-Whites. However, NH-Whites had significantly higher odd of CHD than NH-Blacks, NH-Asians, and Hispanics.

Beyond traditional thoughts that Asians including Asian Americans had lower risk of CVD as compared to the West, the present study is the first to examine and add new evidence to the body of literature regarding CVD risk, that of sub-groups of NH-Asians, Filipino Americans had significantly higher odds of hypertension than NH-Whites. Filipino and Indian Americans had significantly higher odds of DM than NH-Whites. These findings related to South Asians are consistent with our recent studies using data from the WHO coordinated World Health Surveys. A higher risk and prevalence of obesity and insulin resistance in South Asians might partially explain the racial and ethnic differences between South Asians and Whites (9). As there was no previous report that used a representative sample of Filipino Americans on the comparison of the study of interest between NH-Whites, and no data on serum and urine biomarker measures in the NHIS, we are unable to explain the racial and ethnic difference using the present data. Nevertheless, from prevention point of view, findings from the present study have an immediate impact on creating appropriate prevention strategies of CVD and DM across NH-Asian populations in the U.S.

In the study, we further observed that cigarette smoking appeared to have a lower impact (assessed by age-sex-adjusted odds ratios) on the risk of hypertension, CHD, stroke, and DM, but obesity appeared to have a higher impact on hypertension, CHD, and stroke in NH-Asians as compared to NH-Whites, NH-Blacks, and Hispanics. Although it is beyond the scope of further examination and discussion in the present study, the findings may emphasize that there are potentially different effects of different risk factors on the study outcomes by different race/ethnicity. It absolutely calls for further etiologic and mechanism studies.

As compared to former smokers, current smokers appeared to have lower odds of hypertension, CHD, stroke, and DM. It is likely due to the study data from cross-sectional designs that may cause “prevalence bias.” It may have occurred that patients with previous smoking status quit smoking after they were diagnosed with a disease (10). On alcohol consumption, former drinkers had a higher risk of hypertension, CHD, stroke, and DM. However, current drinking showed a protective effect on the study outcomes across all racial/ethnic groups. Although a possible “prevalence bias” may exist in this association as well, several studies have suggested there is a U-shaped association of alcohol consumption with CVD and DM (10–13).

The present study has several strengths. First, the results, on the basis of nationally representative datasets, provide new evidence of cardiovascular health and disparity across multi-racial/ethnic populations in the U.S. Although racial/ethnic disparities in CVD and DM have been reported in a number of studies, data from sub-groups of NH-Asian population is extremely limited. The current study fills in this gap by using a large-scale dataset from the NHIS. Finally, findings from the study not only add to new evidence of multiple minority cardiovascular health status, but also further address the importance of SES and lifestyle-related factors as predictors of cardiovascular health.

Similar to any study, the present study has several limitations. First, the findings are on the basis of data obtained from cross-sectional surveys, therefore, any cause-effect association between the predictors and outcomes cannot be interpreted (10). Second, the study outcomes were self-reports of physician-diagnosis of diseases (hypertension, CHD, stroke, and DM), information bias may occur. It should be noted that self-reports of physician-diagnosis of disease have been confirmed as a valid approach in population health surveys (14, 15). Third, the present study may have underestimated the prevalence of hypertension, CHD, stroke, and DM because no physical examination and measures of biomarkers from the blood sample were conducted. Last, but not least, the sample sizes of subgroups of NH-Asians are still small, as shown by a wider OR 95% CI (Figure 1C), further studies are needed by increasing the study sample sizes.

Despite these limitations, two clear and important conclusions follow the present study. First, CVD and DM disproportionately affect the U.S. multi-racial and ethnic population. Second, although lifestyle-related risk factors are significantly associated with increased odds of CVD and DM, the magnitudes of these factors on the study outcomes are different by racial and ethnic groups.

Longjian Liu and Ana E. Núṅez made the analysis design. Longjian Liu and Hui Liu did data analysis. Longjian Liu wrote the manuscript. Yuan An, Ming Chen, Jixiang Ma, Edgar Y. Chou, Zhengming Chen and Howard J. Eisen did critical review and gave valuable comments on this paper.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.